Search

We propose a real-time time-dependent ab initio approach within a configuration-interaction-singles ansatz to decompose the high-harmonic generation (HHG) signal of molecules in terms of individual molecular-orbital (MO) contributions. Calculations have been performed by propagating the time-dependent Schrödinger equation with complex energies, in order to account for ionization of the system, and by using tailored Gaussian basis sets for high-energy and continuum states. We have studied the strong-field electron dynamics and the HHG spectra in aligned CO2 and H2O molecules. Contribution from MOs in the strong-field dynamics depends on the interplay between the MO ionization energy and the coupling between the MO and the laser-pulse symmetries. Such contributions characterize different portions of the HHG spectrum, indicating that the orbital decomposition encodes nontrivial information on the modulation of the strong-field dynamics. Our results correctly reproduce the MO contributions to HHG for CO2 as described in the literature experimental and theoretical data and lead to an original analysis of the role of the highest occupied molecular orbitals HOMO, HOMO-1, and HOMO-2 of H2O according to the polarization direction of the laser pulse. [ABSTRACT FROM AUTHOR]

The structures and chemical bond evolution of ditantalum doped carbon clusters Ta2Cn−/0 (n = 1–7) were studied via size-selected anion photoelectron spectroscopy and theoretical calculations. It is found that Ta2C−/0 has a triangular structure and Ta2C2−/0 has a quasi-rhombus structure with C2v symmetry. Ta2C3− has a quasi-planar structure with a carbon atom and a C2 unit interacting with two tantalum atoms, and the lowest-energy isomer of neutral Ta2C3 has a triangular bipyramid structure with three carbon atoms around the Ta2 unit. Ta2C4−/0 has two C2 units connected with the Ta2 unit in parallel. Two isomers of Ta2C5− are observed, where both isomers have one carbon atom and two C2 units bound to the Ta2 unit in different ways. The most stable structure of neutral Ta2C5 has one carbon atom added on top of the Ta2C4 cluster. The most stable structures of Ta2C6-7−/0 can be viewed as a C2 unit and a C3 unit capping a butterfly like Ta2C4 structure, respectively. Molecular orbital analysis shows that neutral Ta2C3 has a large gap between its highest occupied molecular orbital and lowest unoccupied molecular orbital. Chemical bonding analysis reveals that the Ta–Ta interactions in Ta2Cn−/0 (n = 1–7) clusters are slightly weaker than the Ta–Ta interaction in bare Ta2 due to the participation in forming multicenter bonds. [ABSTRACT FROM AUTHOR]

In this study, the effects of chlorine substitution on the valence orbitals and electronic states of 3-chloropyridine (3-CP) were investigated utilizing high-resolution vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy and computational methods. High-quality vibrational spectra were obtained from the VUV-MATI spectra of 3-CP isotopomers (35Cl and 37Cl), revealing high-quality vibrational spectra for the lowest cationic states. The adiabatic ionization energies (AIEs) of these isotopomers were accurately determined, providing detailed information about the electronic structure and ionization dynamics. Intense spectra peaks were linked with the D1 excited state of the 3-CP cation, with vibronic transitions in this state closely matching those predicted by Franck–Condon simulations. This provided insights into the cationic structure and the roles of the highest occupied molecular orbital (HOMO) and the HOMO-1. The HOMO was primarily a π orbital of the pyridine ring, while the HOMO-1 consisted of nonbonding orbitals. The AIEs suggested that meta-chlorine substitution stabilizes nonbonding orbitals less effectively than ortho substitution, indicating closely spaced electronic states in the 3-CP cation. Minor discrepancies in vibrational frequencies and intensities, particularly above 800 cm−1, suggested the presence of vibronic coupling, warranting further investigation. Overall, this study provided a comprehensive understanding of the vibronic and ionization properties of 3-CP, emphasizing the influence of the position of the chlorine substitution on molecular orbitals and the value of advanced theoretical and experimental approaches for analyzing the vibrational spectra of complex molecules. [ABSTRACT FROM AUTHOR]

In quantum chemistry, Lowest Unoccupied Molecular Orbital (LUMO) is important for studying various chemical processes, including photochemical reactions, electron attached states, and electron excites states. Recently, an effective method has been introduced that involves the use of the Parametric Equation of Motion (PEM) in conjunction with the nuclear charge stabilization method for precise identification of true LUMO. However, the inclusion of extra diffuse functions in the basis set, which is necessary for describing electron-attached and electron-excited states, can cause issues due to the presence of the same symmetry states, leading to avoided crossing. Identifying the true LUMO among these avoided crossings is challenging due to the mixing of states and the exchange of their orbital character. This article introduces a modification of the PEM to identify the true LUMO by preventing the stabilization of specific states involved in avoided crossings. The present method is highly effective and requires minimal computational cost. [ABSTRACT FROM AUTHOR]

3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) is one of the third-generation energetic compounds with excellent comprehensive properties, which can be added to polymer bonded explosive (PBX) to improve energy levels and regulate sensitivity, so the compatibility of DNTF with other components in PBX, especially the binder, is the first question. Herein, two typical hydrocarbon polymers commonly used in PBX, which are hydroxyl-terminated polybutadiene (HTPB) and polyisobutylene (PIB), were selected as the binder, and the compatibility of HTPB and PIB with DNTF was investigated by differential scanning calorimetry (DSC), the vacuum stability test (VST), and in situ infrared spectroscopy (in situ IR). The results of compatibility experiments were verified by using the binding energy and solubility parameter criteria in molecular dynamics (MD). Experimental and MD simulation results showed that DNTF could be compatible with PIB but incompatible with HTPB. The frontier molecular orbital theory in quantum chemistry (QC) was adopted to explore the frontier orbital electron distribution and energy levels of DNTF/HTPB and DNTF/PIB composite systems to better understand the microscopic compatibility mechanism. The compatibility results of the two composite systems were explained from the perspective of electron transfer. All these can deduce that a hydrocarbon polymer binder with a saturated carbon–hydrogen bond at the end of the molecular chain has good compatibility with DNTF, compared with a hydroxyl group, which has bad compatibility with DNTF. [ABSTRACT FROM AUTHOR]

We perform detailed potential energy surface explorations of BeM(CO)3− (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt) using both single-reference and multireference-based methods. The present results at the CASPT2(12,12)/def2-QZVPD//M06-D3/def2-TZVPPD level reveal that the global minimum of BeM(CO)3− (M = Co, Rh, Ir) and BePt(CO)3 is a C3v symmetric structure with an 1A1 electronic state, where Be is located in a terminal position bonded to M along the center axis. For other cases, the C3v symmetric structure is a low-lying local minimum. Although the present complexes are isoelectronic with the recently reported BFe(CO)3− complex having a B–Fe quadruple bond, radial orbital-energy slope (ROS) analysis reveals that the highest occupied molecular orbital (HOMO) in the title complexes is slightly antibonding in nature, which bars a quadruple bonding assignment. Similar weak antibonding nature of HOMO in the previously reported BeM(CO)4 (M = Ru, Os) complexes is also noted in ROS analysis. The bonding analysis through energy decomposition analysis in combination with the natural orbital for chemical valence shows that the bonding between Be and M(CO)3q (q = −1 for M = Co, Rh, Ir and q = 0 for M = Ni, Pd, Pt) can be best described as Be in the ground state (1S) interacting with M(CO)30/− via dative bonds. The Be(spσ) → M(CO)3q σ-donation and the complementary Be(spσ) ← M(CO)3q σ-back donation make the overall σ bond, which is accompanied by two weak Be(pπ) ← M(CO)3q π-bonds. These complexes represent triply bonded terminal beryllium in an unusual zero oxidation state. [ABSTRACT FROM AUTHOR]

Continuum- or discrete-polarizable models for the study of optoelectronic processes in embedded subsystems rely mostly on the restriction of the surrounding electronic dielectric response to its low frequency limit. Such a description hinges on the assumption that the electrons in the surrounding medium react instantaneously to any excitation in the central subsystem, thus treating the environment in the adiabatic limit. Exploiting a recently developed embedded GW formalism with an environment described at the fully ab initio level, we assess the merits of the adiabatic limit with respect to an environment where the full dynamics of the dielectric response are considered. Furthermore, we show how to properly take the static limit of the environment's susceptibility by introducing the so-called Coulomb-hole and screened-exchange contributions to the reaction field. As a first application, we consider a C60 molecule at the surface of a C60 crystal, namely, a case where the dynamics of the embedded and embedding subsystems are similar. The common adiabatic assumption, when properly treated, generates errors below 10% on the polarization energy associated with frontier energy levels and associated energy gaps. Finally, we consider a water molecule inside a metallic nanotube, the worst case for the environment's adiabatic limit. The error on the gap polarization energy remains below 10%, even though the error on the frontier orbital polarization energies can reach a few tenths of an electronvolt. [ABSTRACT FROM AUTHOR]

Rare-earth doped materials are of immense interest for their potential applications in linear and nonlinear photonics. There is also intense interest in sub-nanometer gold clusters due to their enhanced stability and unique optical, magnetic, and catalytic properties. To leverage their emergent properties, here we report a systematic study of the geometries, stability, electronic, magnetic, and linear and nonlinear optical properties of Au5RE (RE = Sc, Y, La–Lu) clusters using density-functional theory. Several low-energy isomers consisting of planar or non-planar configurations are identified. For most doped clusters, the non-planar configuration is energetically favored. In the case of La-, Pm-, Gd-, and Ho-doped clusters, a competition between planar and non-planar isomers is predicted. A distinct preference for the planar configuration is predicted for Au5Eu, Au5Sm, Au5Tb, Au5Tm, and Au5Yb. The distinction between the planar and non-planar configurations is highlighted by the calculated highest frequencies, with the stretching mode of the non-planar configuration predicted to be stiffer than the planar configuration. The bonding analysis reveals the dominance of the RE-d orbitals in the formation of frontier molecular orbitals, which, in turn, facilitates retaining the magnetic characteristics governed by RE-f orbitals, preventing spin-quenching of rare earths in the doped clusters. In addition, the doped clusters exhibit small energy gaps between frontier orbitals, large dipole moments, and enhanced hyperpolarizability compared to the host cluster. [ABSTRACT FROM AUTHOR]

Porphyrins are prime candidates for a host of molecular electronics applications. Understanding the electronic structure and the role of anchoring groups on porphyrins is a prerequisite for researchers to comprehend their role in molecular devices at the molecular junction interface. Here, we use the density functional theory approach to investigate the influence of anchoring groups on Ni and Zn diphenylporphyrin molecules. The changes in geometry, electronic structure, and electronic descriptors were evaluated. There are minimal changes observed in geometry when changing the metal from Ni to Zn and the anchoring group. However, we find that the distribution of electron density changes when changing the anchoring group in the highest occupied and lowest unoccupied molecular orbitals. This has a direct effect on electronic descriptors such as global hardness, softness, and electrophilicity. Additionally, the optical spectra of both Ni and Zn diphenylporphyrin molecules exhibit either blue or red shifts when changing the anchoring group. These results indicate the importance of the anchoring group on the electronic structure and optical properties of porphyrin molecules. [ABSTRACT FROM AUTHOR]

Resonant Auger processes provide a unique perspective on electronic interactions and excited vibrational and electronic states of molecular ions. Here, new data are presented on the resonant Auger decay of excited CH3I in the region just below the I 4d−1 ionization threshold. The resonances include the Rydberg series converging to the five spin–orbit and ligand-field split CH3I (I 4d−1) thresholds, as well as resonances corresponding to excitation from the I 4d5/2,3/2 orbitals into the σ* lowest unoccupied molecular orbital. This study focuses on participator decay that populates the lowest lying states of CH3I+, in particular, the X ̃ 2E3/2 and 2E1/2 states, and on spectator decay that populates the lowest-lying (CH3I2+)σ* states of CH3I+. The CH3I (I 4d−1)σ* resonances are broad, and dissociation to CH3 + I competes with the autoionization of the core-excited states. Auger decay as the molecule dissociates produces a photoelectron spectrum with a long progression (up to v3+ ∼ 25) in the C–I stretching mode of the X ̃ 2E3/2 and 2E1/2 states, providing insights into the shape of the dissociative core-excited surface. The observed spectator decay processes indicate that CH3I+ is formed on the repulsive wall of the lower-lying (CH3I2+)σ* potentials, and the photon-energy dependence of the processes provides insights into the relative slopes of the (4d−1)σ* and (CH3I2+)σ* potential surfaces. Data are also presented for the spectator decay of higher lying CH3I (I 4d−1)nl Rydberg resonances. Photoelectron angular distributions for the resonant Auger processes provide additional information that helps distinguish these processes from the direct ionization signal. [ABSTRACT FROM AUTHOR]

In the past decade, the quantum chemical version of the density matrix renormalization group method has established itself as the method of choice for strongly correlated molecular systems. However, despite its favorable scaling, in practice, it is not suitable for computations of dynamic correlation. Several approaches to include that in post-DMRG methods exist; in our group, we focused on the tailored coupled cluster (TCC) approach. This method works well in many situations; however, in exactly degenerate cases (with two or more determinants of equal weight), it exhibits a bias toward the reference determinant representing the Fermi vacuum. Although sometimes it is possible to use a compensation scheme to avoid this bias for energy differences, it is certainly a drawback. In order to overcome this bias of the TCC method, we have developed a Hilbert-space multireference version of tailored CC, which can treat several determinants on an equal footing. We have implemented and compared the performance of three Hilbert-space multireference coupled cluster (MRCC) variants—the state universal one and the Brillouin–Wigner and Mukherjee's state specific ones. We have assessed these approaches on the cyclobutadiene and tetramethyleneethane molecules, which are both diradicals with exactly degenerate determinants at a certain geometry. We have also investigated the sensitivity of the results on the orbital rotation of the highest occupied and lowest unoccupied molecular orbital (HOMO–LUMO) pair, as it is well known that Hilbert-space MRCC methods are not invariant to such transformations. [ABSTRACT FROM AUTHOR]

Non-fullerene electron acceptors have emerged as promising alternatives to traditional electron-acceptors in the active layers of organic photovoltaics. This is due to their tunable energy levels, optical response in the visible light spectrum, high electron mobility, and photochemical stability. In this study, the electronic properties of two representative non-fullerene acceptors, ITIC and Y5, have been calculated within the framework of density functional theory using a range of hybrid and non-hybrid density functionals. Screened range-separated hybrid (SRSH) approaches were also tested. The results are analyzed in light of the previously reported experimental outcomes. Specifically, we have calculated the oxidation and reduction potentials, fundamental and optical gaps, the highest occupied molecular orbital and lowest unoccupied molecular orbital energies, and exciton binding energies. Additionally, we have investigated the effects of the medium dielectric constant on these properties employing a universal implicit solvent model. It was found that hybrid functionals generally perform poorly in predicting oxidation potentials, while non-hybrid functionals tend to overestimate reduction potentials. The inclusion of a large Hartree–Fock contribution to the global or long range was identified as the source of inaccuracy for many hybrid functionals in predicting both redox potentials and the fundamental and optical gaps. Corroborating with the available literature, ∼50% of all tested functionals predicted very small exciton binding energies, within the range of ±0.1 eV, that become even smaller by increasing the dielectric constant of the material. Finally, the OHSE2PBE and tHCTHhyb functionals and the optimal tuning SRSH approach emerged as the best-performing methods, with good accuracy in the description of the electronic properties of interest. [ABSTRACT FROM AUTHOR]

Note: Photoelectron imaging of MnO3- to probe its nuclear and electronic structure In this note, we revisit the MnO SB 3 sb SP - sp photoelectron spectrum using photoelectron imaging and reassess the assignment, showing that in fact, MnO SB 3 sb is planar in its ground electronic state. Using anion photoelectron spectroscopy, a previous study by Gutsev I et al. i [1] found the ground state of MnO SB 3 sb to have a trigonal pyramidal structure. A 126(22), 3495-3501 (2022). 10.1021/acs.jpca.2c02008 9 J. B. Kim, M. L. Weichman, and D. M. Neumark, "Structural isomers of Ti2O4 and Zr2O4 anions identified by slow photoelectron velocity-map imaging spectroscopy", J. Am. Chem. Soc. 136(19), 7159-7168 (2014). 10.1021/ja502713v 10 V. D. Moravec and C. C. Jarrold, "Study of the low-lying states of NiO- and NiO using anion photoelectron spectroscopy", J. Chem. Phys. [Extracted from the article]

Comprehensive Summary: Near‐infrared (NIR)‐absorbing polymerized small molecule acceptors (PSMAs) based on a Y‐series backbone (such as PY‐IT) have been widely developed to fabricate efficient all‐polymer solar cells (all‐PSCs). However, medium‐bandgap PSMAs are often overlooked, while they as the third component can be expected to boost power conversion efficiencies (PCEs) of all‐PSCs, mainly due to their up‐shifted lowest unoccupied molecular orbital (LUMO) energy level, complimentary absorption, and diverse intermolecular interaction compared to the NIR‐absorbing host acceptor. Herein, an IDIC‐series medium‐bandgap PSMA (P‐ITTC) is developed and introduced as the third component into D18/PY‐IT host, which can not only form complementary absorption and cascade energy level, but also finely optimize active layer morphology. Therefore, compared to the D18/PY‐IT based parental all‐PSCs, the ternary all‐PSCs based on D18/PY‐IT:P‐ITTC obtain an increased exciton dissociation, charge transport, carrier lifetime, as well as suppressed charge recombination and energy loss. As a result, the ternary all‐PSCs achieve a high PCE of 17.64% with a photovoltage of 0.96 V, both of which are among the top values in layer‐by‐layer typed all‐PSCs. This work provides a method for the design and selection of the medium‐bandgap third component to fabricate efficient all‐PSCs. [ABSTRACT FROM AUTHOR]

Fourteen substituted diketopyrrolopyrrole (DPP) molecules in a donor (D)–acceptor (DPP)–donor (D) arrangement were designed. We employed density functional theory, time‐dependent DFT, DFT‐MRCI and the ab initio wave function second‐order algebraic diagrammatic construction (ADC(2)) methods to investigate theoretically these systems. The examined aromatic substituents have one, two, or three hetero‐ and non‐hetero rings. We comprehensively investigated their optical, electronic, and charge transport properties to evaluate potential applications in organic electronic devices. We found that the donor substituents based on one, two, or three aromatic rings bonded to the DPP core can improve the efficiency of an organic solar cell by fine‐tuning the highest occupied molecular orbital/lowest unoccupied molecular orbital levels to match acceptors in typical bulk heterojunctions acceptors. Several properties of interest for organic photovoltaic devices were computed. We show that the investigated molecules are promising for applications as donor materials when combined with typical acceptors in bulk heterojunctions because they have appreciable energy conversion efficiencies resulting from their low ionization potentials and high electron affinities. This scenario allows a more effective charge separation and reduces the recombination rates. A comprehensive charge transfer analysis shows that D–A (DDP)–D systems have significant intramolecular charge transfer, further confirming their promise as candidates for donor materials in solar cells. The significant photophysical properties of DPP derivatives, including the high fluorescence emission, also allow these materials to be used in organic light‐emitting diodes. [ABSTRACT FROM AUTHOR]

Inverted (p‐i‐n) perovskite solar cells (PSCs) have experienced remarkable advancements in recent years, which is largely attributed to the development of novel hole‐transport layer (HTL) self‐assembled monolayer (SAM) materials. Methoxy (MeO−) groups are typically introduced into SAM materials to enhance their wettability and effectively passivate the perovskite buried interface. However, MeO‐based SAM materials exhibit a mismatch in highest occupied molecular orbital (HOMO) levels with perovskite layer due to the strong electron‐donating capability of methoxy group. In this work, we introduced a methylthio (MeS−) substituent that is superior to methoxy as a highly versatile self‐assembled molecular design strategy. As a soft base, sulfur atom forms a stronger Pb−S bond than oxygen. Additionally, within the CbzPh series of SAM materials, MeS−CbzPh demonstrates a more optimal HOMO level and enhanced hole transport properties. Consequently, the MeS−CbzPh HTL based device achieved an impressive power conversion efficiency (PCE) of 26.01 % and demonstrated high stability, retaining 93.3 % efficiency after 1000 hours of maximum power point tracking (MPPT). Moreover, in comparison with the commonly used 4PACz‐based SAM molecular series, MeS‐4PACz also exhibited the best performance among its peers. Our work provides valuable insights for the molecular design of SAM materials, offering a highly versatile functional substituent group. [ABSTRACT FROM AUTHOR]

Photosensitizers with near‐infrared (NIR) excitation, especially above 800 nm which is highly desired for phototherapy, remain rare due to the fast nonradiative relaxation process induced by exciton‐vibration coupling. Here, a diketopyrrolopyrrole‐derived photosensitizer (DTPA‐S) is developed via thionation of carbonyl groups within the diketopyrrolopyrrole skeleton, which results in a large bathochromic shift of 81 nm, endowing the photosensitizer with strong NIR absorption at 712 nm. DTPA‐S is then introduced with a functional biomolecule (N3‐PEG2000‐RGD) via click reaction for the construction of integrin αvβ3 receptor‐targeted nano‐micelles (NanoDTPA‐S/RGD), which endows the photosensitizer with a further superlarge absorption redshift of 138 nm, thus extending the absorption maxima to ≈850 nm. Remarkably, thiocarbonyl substitution increases the nonbonding characters in frontier molecular orbitals, which can effectively suppress the nonradiative vibrational relaxation process via reducing the reorganization energy, enabling efficient reactive oxygen species (ROS) generation under 880 nm excitation. Screened by in vitro and in vivo assays, NanoDTPA‐S/RGD with high water solubility, excellent tumor‐targeting ability, and photodynamic/photothermal therapy synergistic effect exhibits satisfactory phototherapeutic performance. Overall, this study demonstrates a new design of efficient NIR‐triggered diketopyrrolopyrrole photosensitizer with facile installation of functional biomolecules for potential clinical applications. [ABSTRACT FROM AUTHOR]

Opto‐electronic properties and device performance of organic semiconductors are mainly determined by energy levels of their frontier molecular orbitals, e.g. lowest unoccupied molecular orbital (ELUMO) and highest occupied molecular orbital (EHOMO) in the ground state, first singlet state (ES1) and first triplet state (ET1) in the excited state. These energy levels are always intricately intertwined. Herein, we report a series of monodisperse oligomers based on double B←N bridged bipyridine (BNBP) units. With the increasing number of repeating units, the oligomers exhibit gradually downshifted ELUMO and nearly unchanged EHOMO due to the different distribution of the frontier molecular orbitals of the oligomers. Moreover, the oligomers exhibit gradually decreasing ES1 and nearly unchanged ET1 because of the different contributions of the charge transfer component in the excited state. This work provides new insight into energy level tuning of organic semiconductors, which is important for high‐performance organic opto‐electronic devices. [ABSTRACT FROM AUTHOR]

Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two‐centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enzymes show no non‐turnover voltammetry on Au(111)‐surfaces modified by thiol based self‐assembled molecular monolayers, but dioxygen or nitrite substrate triggers strong electrocatalytic signals. Scanning tunnelling microscopy also shows high conductivity only when dioxygen or nitrite is present. Atomic force microscopy shows constant CuNIR height but pronounced structural expansion in the electrocatalytic range on nitrite binding. We have recently offered a rationale, based on ab initio quantum chemical studies of water/nitrite substitution in a 740‐atom CuNIR fragment. Presently we provide much more detailed structural assignment mapped to single‐residue resolution. NO2−‐binding induces both a 2 Å Cu−Cu distance increase, and pronounced frontier orbital delocalization strongly facilitating ET between the Cu regions. The conformational changes transmit from the catalytic Type II centre to the electron inlet Type I centre, via the His129‐Cys130 ligands, and via Type I–Cys130 or Type I‐His129 ending at Type II Asp92. The ET patterns are reflected in different atomic Mulliken charges in the water and nitrite CuNIR fragment. [ABSTRACT FROM AUTHOR]

The 1-(3-nitro-phenyl)-5-phenyl-penta-2,4-dien-1-one (1NP5PP) molecule is subjected to detailed spectroscopic investigation by analyzing the spectra obtained by FT-IR and FT-Raman methods. The computational analysis were performed at DFT level using B3LYP/6-311++G(d, p) basis set. With the support of potential energy distribution the entire vibrational assignment was conducted. A frontier molecular orbital study reveals energy gap is small for the molecule. Molecular electrostatic potential surface shows that highest electronegative around oxygen atom in ethylenic bridge and electropositive region spreads through all the hydrogen atoms in the molecule. Natural bond orbital, nonlinear optical analysis, and Fukui function studies were conducted for the present molecule. The electron distribution and reactive site on the surface of the molecule were analyzed using electron localization function and localized orbital locator analysis. In molecular docking studies the interaction observed between MPRO and the 1NP5PP ligand shows the good degree of inhibition. The above mentioned analogy reflects that 1NP5PP has adequate biological properties. [ABSTRACT FROM AUTHOR]

We report here the synthesis of the two novel molecules 5-((5-hexyl-2,4-dihydroxyphenyl)diazenyl)isophthalic acid (3a) and 5-((5-ethyl-2,4-dihydroxyphenyl)diazenyl)isophthalic acid (3b). The structures of the 3a and 3b were confirmed by using 1H-NMR,13C-NMR, FT-IR, UV-vis, and HR-ESI-MS techniques. The optimized molecular geometry, vibrational frequency,1H- and 13C-NMR spectra calculations were performed using the DFT/B3LYP method with a 6-311G(d,p) basis set. The frontier molecular orbitals and electronic transition wavelengths were calculated at the level of TD-DFT/CAM-B3LYP/6-311G(d,p). The experimental data obtained for the synthesized molecules were in good agreement with the theoretical ones. The calculated HOMO-LUMO band gap revealed that 3a has a softer character and may be more reactive in chemical reactions. Important ADMET parameters of the compounds were also calculated, and the obtained physicochemical, pharmacokinetic, drug similarity, and toxicity data were at the desired level for a candidate bioactive compound. In order to examine the potential anticancer or antibacterial properties of newly synthesized azo molecules, molecular docking studies were performed using four different proteins. The best interaction was determined to be between 3a and VEGFR2 (PDB ID: 2XIR) with a binding energy of 9.0 kcal/mol. Moreover, a 50 ns MD simulation study for 3a-2XIR revealed that the complex maintained both its structural integrity and molecular interactions throughout the simulation. [ABSTRACT FROM AUTHOR]

The widely used spiro‐OMeTAD exhibits moderate interaction with the perovskite layer, which does not decrease the defect on the perovskite surface, thus limiting the photoelectric performance of perovskite solar cells. In this work, the spiro‐OMeTAD structure is functionalized with chlorine (Cl), resulting in a new material labeled spiro‐mCl, which interacts more effectively with the perovskite and passivating interface defects. In addition, the strong electronegativity of Cl lowers the Highest Occupied Molecular Orbitals (HOMO) energy level of spiro‐mCl, resulting in a better match with the valence band of perovskite. Additionally, the asymmetry introduced by Cl enhances the hole mobility and increases the glass transition temperature of spiro‐mCl. As a result, the device incorporating spiro‐mCl achieved an open‐circuit voltage of 1.16 V and a remarkable power conversion efficiency of 25.26% (certified at 24.88%), marking it as one of the highest‐performing spirobifluorene‐based HTMs in PSCs. Importantly, this device also demonstrated significantly improved operational stability compared to the one utilizing spiro‐OMeTAD. [ABSTRACT FROM AUTHOR]

To examine the relationship between chemical structure modification and photovoltaic performance, we designed six metal-free organic molecules (M2-M7) of structure D-π1-A-π2-A based on the base molecule M1 of structure D-π1-π2-A, introducing a new auxiliary acceptor (A) and varying the π2-spacer at the same time, to study their performance in dye-sensitized solar cells. Using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, several parameters were calculated and discussed, including LUMO and HOMO energy levels of the HOMO–LUMO energy gap, frontier molecular orbitals, absorption properties, nonlinear optical properties (NLO), light-harvesting efficiency (LHE), electron injection driving force (ΔGinj), dye regeneration driving force (ΔGreg), reorganization energy (λtotal), and vertical dipole moment (μnormal) of the studied dyes (M1–M7). The results of the proposed dyes proved promising for use as sensitizers in the DSSC device due to their lower energy gap, red- and NIR-shifted absorption band, higher LHE and NLO properties, lower ΔGreg and λtotal values, negative ΔGinj value, and higher μnormal value reflecting higher VOC compared to the reference dye M1. The results of these proposed dyes (M2-M7) will be considered favorable indicators for experimenters to synthesize effective dyes for use in the DSSC device. [ABSTRACT FROM AUTHOR]

Polymeric hole transport materials (HTMs) have emerged because of their potential to produce dopant‐free, efficient, and stable perovskite solar cells (PSCs). Therefore, we engineered 10 novel donor materials (SMH1–SMH10) containing phenanthrocarbazole‐based polymeric structures for organic and PSCs. These molecules underwent bridging‐core modifications using different spacers, such as furan (N1), pyrrole (N2), benzene (N3), pyrazine (N4), dioxane (N5), isoxazole (N6), isoindole (N7), indolizine (N8), double bond (N9), and pyrimidine (N10), in comparison to reference molecule R. The study examined the structure–property relationship and the impact of these modifications on the optical, photovoltaic, photophysical, and optoelectronic characteristics of the newly designed SMH1–SMH10 series. Density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) calculations were conducted to analyze frontier molecular orbitals, density of states, reorganization energies, open‐circuit voltage, transition density matrix, and charge transfer processes. Results show that the newly designed molecules (SMH1–SMH10) exhibited superior optoelectronics characteristics compared to the R molecule. Among these, SMH4 is the most promising candidate, with a small band gap (2.79 eV), low electron and hole mobility (λe 0.0028 eV, λh 0.0020 eV), lower binding energy (Eb 0.58 eV), high λmax values (656.42 nm in gas, 573.34 nm in chlorobenzene), and a high Voc of 1.30 V. Therefore, this study demonstrated that bridging‐core modifications offer a simple and effective strategy for designing desirable characteristics molecules for photovoltaic applications. [ABSTRACT FROM AUTHOR]

The present work explored the effect of –OH group substitution (o/p) on the spectral and electrochemical behavior of N‐benzylideneaniline. The geometry optimization of unsubstituted and (o/p)‐OH‐substituted analogs revealed the coplanarity of the molecules. The vibrational spectra of the compounds were computed using density functional theory (DFT) and compared with the experimental data. The observed bands were assigned based on total energy distribution (TED). Predicted electronic absorption spectra from time‐dependent density functional theory (TD‐DFT) calculation were compared with the UV–visible spectra of the molecules. The analysis of the lowest spin‐allowed (singlet‐singlet) excited states divulged possible electronic transition. The o‐substituted benzylideneaniline possessed the lowest highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy gap among the substituted and unsubstituted analogs. The intramolecular contacts were interpreted using natural bond orbital and localized molecular orbital analysis. The –CH=N– linkage was investigated as a bridge for the electron delocalization from the donor to acceptor moieties. The manifestation of a reduction peak in the cyclic voltammetric studies confirmed the electrochemical behavior in the –OH‐substituted molecule, which was diffusion‐controlled. The discrepancy in the electrochemical property concerning the position of the –OH substituent of the candidate molecules was put forward. [ABSTRACT FROM AUTHOR]

A novel 2-(2,3,4-trimethoxyphenyl)-1H-phenanthro[9,10-d]imidazole crystal has been reported and characterized by FT-IR, 1H NMR, and 13C NMR spectral techniques. Single-crystal XRD studies reveal that the compound crystallizes into orthorhombic crystal system with Pbcn space group, and crystallographic data have been deposited in the Cambridge crystallographic data centre with CCDC number: 2244532. Various computational analyses such as hydrogen bond analysis, molecular electrostatic potential analysis, natural population analysis, Hirshfeld surface, and Frontier molecular orbital analysis were performed to elucidate the structure of the crystal. The calculation of reorganization energy and coupling constant using DFT methods reveals that the compound could be investigated as a hole transport material. [ABSTRACT FROM AUTHOR]

The discovery of cyclic boron oxide clusters has prompted investigations into their distinctive structures and bonding characteristics. Notably, the majority of reported cyclic boron oxide structures consist predominantly of four to six-membered rings. In this study, we employ theoretical methods to predict the global-minimum (GM) structure of B6O62+. Our analyses, including global-minimum searches and calculations using B3LYP, PBE, PBE0, and single-point CCSD(T), reveal that the D2h B6O62+ (1Ag) configuration represents a planar and tricyclic structure, resulting from the fusion of B3O2/B4O2/B3O2 units. Remarkably, this structure establishes the B6O62+ cluster as the smallest boron oxide cluster with a planar tricyclic motif. Further bonding analysis indicates that B6O62+ is a weakly antiaromatic system with 12π delocalized electrons. The reported B6O6 has a planar structure with a 6-membered B3O3 ring and 6 π electrons distributed over the ring. Because of the absence of two electrons from the highest occupied molecular orbital (HOMO) of neutral B6O6, the structure of B6O62+ is distinctly different from that of B6O6. [ABSTRACT FROM AUTHOR]

To understand the scavenging action of chlorophyll (Chla) found in most of the vegetables towards hydroxyl ( OH ∙ ) radicals, its reactions with OH ∙ radicals via RAF, HAT, and SET mechanisms have been investigated theoretically using two layer ONIOM [M06-2X/6-31G(d) (High):M06-2X/3-21G (Low)] method and M06-2X/6–311 + G(d,p) level of density functional theory. The molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) plots, HOMO–LUMO energy gap, global hardness (η), global softness (S), electronegativity (χ), and electrophilicity index (ω) of Chla molecule were computed and analyzed to determine its stability and reactive sites. It is found that RAF and HAT reactions are exergonic in both gaseous and aqueous media whereas SET reactions are endergonic in both media. However, all the RAF, HAT and SET reactions studied here are found to be more favourable in aqueous media vs. gas phase. The rate constants of RAF reactions at different sites are found to be of the order of ~ 6.2 × 107–1.8 × 1010 s−1 indicating that RAF reactions would be appreciably fast. This study concludes that chlorophyll can efficiently scavenge OH ∙ radicals preferably via RAF and HAT mechanisms and intake of water with chlorophyll can enhance its scavenging actions. [ABSTRACT FROM AUTHOR]

4-(2-amino-2-oxoethyl) phenyl 4-methylbenzenesulfonate (APMBS), a novel compound, has been synthesized and characterized by spectro-analytical techniques. X-ray diffraction data reveals it crystallizes in the triclinic crystal system with space group P 1 ¯ . The structure is stabilized through strong N–H⋯O, weak C–H⋯O and C–H⋯π hydrogen bond interactions yielding a supramolecular structure. The N1A–H1AA⋯O4A, C4–H4⋯O3, and C14–H14⋯Cg1 (Ring: C8–C13) interactions link the molecules into dimers, while the interaction C9-H9–O2 results in the formation of a molecular chain along the a-axis. The optimized structural geometry, by and large, as calculated using DFT and HF techniques is in conformity with the corresponding X-ray data. The DFT computation further aid in the follow up investigations including frontier molecular orbitals (FMOs), density of states (DOS), atomic charges, and molecular electrostatic potential surface (MEP). For a comprehensive description of various molecular intersections, Hirsheld surface and fingerprint plots analysis has been reported, besides the combined atoms-in-molecules (QTAIM) and reduced density gradient (RDG) analysis. Docking studies have been performed against the target protein Tubulin-Colchicine: Stathmin-Like Domain Complex. [ABSTRACT FROM AUTHOR]

Although the concept of geopolymers was proposed over 40 years ago, there still remains a lack of clarity regarding their atomic-level structure and formation. In this study, the Dmol3 quantum chemistry calculation program, based on density functional theory (DFT), was used to determine a range of electronic structural properties associated with the initial, intermediate (IM), transition (TS), and final states of Al2O3/[Al(OH)4]− conversion reactions in the alkali-activator. The properties analyzed included total energy, Gibbs free energy, electrostatic potential (ESP), Fukui functions, and frontier orbitals, comprising the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO). The simulation results indicated that electrons were transferred from the HOMO of O in H2O and OH− to the LUMO of Al in (AlO2)− or (AlO)+ , leading to an increase in the LUMO energy level of Al and a reduction in the chemical reactivity of the newly formed Al monomers. The transformation processes from Al2O3 to [Al(OH)4]− involved varying numbers of steps, energy release, and energy barriers. Notably, during the transition state conversion process, the breaking and reformation of O─ H bonds often occurred as necessary conditions for the formation of transition states. These findings have significant implications for the advancement of new technologies based on geopolymer conversion processes. [ABSTRACT FROM AUTHOR]

We developed a high-performance CdSe/ZnS quantum-dot light-emitting diode (QLED) incorporating a hole injection layer (HIL) composed of a solution-processed vanadium oxide (VO) and molybdenum oxide (MoO) mixture. The QLED with a VO:MoO ratio of 1:1 in the HIL demonstrated a current efficiency of 62.0 cd/A, representing a 60% improvement over the QLED utilizing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the HIL. Besides improved performance, the substitution of the highly reactive PEDOT: PSS with chemically stable metal oxides in HIL fabrication is anticipated to enhance device reliability. The highest occupied molecular orbital level of the VO:MoO ratio of 1:1 HIL was higher than that of HILs with other mixing ratios. Additionally, the VO:MoO ratio of 1:1 HIL exhibited higher oxidation number states compared to HILs with other mixing ratios. These characteristics contributed to the superior performance of the QLED with the VO:MoO ratio of 1:1 HIL. Our approach, which employs chemically stable metal oxides as HIL materials for high-performance QLEDs, can advance future QLED technology. [ABSTRACT FROM AUTHOR]

In organic light-emitting diodes (OLEDs), hole transport is typically about two orders of magnitude faster than electron transport. This leads to carrier complexation near the cathode and exciton bursting on the cathode metal surface, greatly reducing the luminescence efficiency of the device. To solve this problem, we constructed a composite buffer layer of poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) synergized with silver nanoparticles (Ag NPs) and introduced it between the anode and the organic layer, which allows the holes to diffuse laterally under the influence of the concentration gradient, so that the luminescent region extended beyond the overlap of the cathode–anode. The lateral diffusion of holes can reduce the accumulation of holes in the device and improve the device stability. More importantly, adding the material C70 with a high highest occupied molecular orbital (HOMO) energy level to form a heterojunction in this buffer layer can further control the lateral diffusion distance and the longitudinal injection rate of holes; when the ratio of the two is 1:1, the carrier balance of the OLED is optimal, and the optical performance is excellent. This work provides a new strategy for OLED current balancing and opens up a new avenue for fabricating high-efficiency OLEDs. [ABSTRACT FROM AUTHOR]

This work presents a multiscale theoretical investigation into the potential of quinoxaline derivatives (Q1–Q6) as corrosion inhibitors for various metals (Fe(110), Cu(111), and Al(110)). Employing a combined approach combining density functional theory (DFT) and Monte Carlo simulations, we explore the relationship between molecular structure, electronic properties, and adsorption behavior. Density functional theory (DFT) and molecular dynamics simulations (MDS) were used to investigate the electronic characteristics of diverse compounds. The study included key parameters including highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (Eg) between ELUMO and EHOMO, dipole moment, global hardness, softness (σ), ionization energy (I), electron affinity (A), electronegativity (χ), back-donation energy Eb−d, global electrophilicity (ω), electron transfer, global nucleophilicity (ε), and total energy (sum of electronic and zero-point energies). These properties, alongside adsorption energies (following the trend Q6 > Q2 > Q3 > Q4 > Q5 > Q1), are used to identify promising inhibitor candidates and establish structure–property relationships governing their effectiveness. The results suggest that inhibitor efficiency increases with a decreasing energy gap between frontier orbitals. Notably, the protonated state of Q6 exhibits high reactivity, low stability, and strong adsorption, making it a potential candidate for further exploration. This comprehensive theoretical approach offers crucial insights for the conceptual development of new and powerful corrosion inhibitors. [ABSTRACT FROM AUTHOR]

The discovery of cyclic boron oxide clusters has prompted investigations into their distinctive structures and bonding characteristics. Notably, the majority of reported cyclic boron oxide structures consist predominantly of four to six-membered rings. In this study, we employ theoretical methods to predict the global-minimum (GM) structure of B6O62+. Our analyses, including global-minimum searches and calculations using B3LYP, PBE, PBE0, and single-point CCSD(T), reveal that the D2h B6O62+ (1Ag) configuration represents a planar and tricyclic structure, resulting from the fusion of B3O2/B4O2/B3O2 units. Remarkably, this structure establishes the B6O62+ cluster as the smallest boron oxide cluster with a planar tricyclic motif. Further bonding analysis indicates that B6O62+ is a weakly antiaromatic system with 12π delocalized electrons. The reported B6O6 has a planar structure with a 6-membered B3O3 ring and 6 π electrons distributed over the ring. Because of the absence of two electrons from the highest occupied molecular orbital (HOMO) of neutral B6O6, the structure of B6O62+ is distinctly different from that of B6O6. [ABSTRACT FROM AUTHOR]

We present here a series of 4,6-diarylpyrimidin-2-amine derivatives (5a-j) with tunable optical properties both in the solid and solution states. Our plug-and-play fluorophore design demonstrates that the aryl groups at the 4th and 6th positions of the 2-aminopyrimidine core enable distinct optical characteristics for each derivative. The fluorophore design concept was validated using theoretical and spectroscopic methods. The designed compounds were synthesised in moderate to good yields, and their structures were confirmed via IR, NMR, HRMS, and single-crystal XRD analyses. Optical studies revealed that varying the aryl substituents significantly impacts absorption, emission, and bandgap values in both phases. The absolute quantum yields (ϕF) of the synthesised derivatives ranged from 8.11 to 71.00% in DMF and 5.86–29.43% in thin films, with fluorescence lifetimes (τ) between 0.8 and 1.5 ns in DMF and 0.63–3.16 ns in films, respectively. CIE (Commission Internationale de l'Éclairage) diagrams indicate blue-green emission for 5a-j in the visible spectrum. The electrochemical analysis confirmed that the HOMO/LUMO (Highest Occupied Molecular Orbital/Lowest Unoccupied Molecular Orbital) energy levels can be modulated by altering the substituent rings. These results highlight the dual-state emission properties of 2-aminopyrimidine fluorophores, demonstrating their potential for a wide range of optoelectronic and advanced applications. [ABSTRACT FROM AUTHOR]

AbstractOxadiazole derivatives containing pyridine moiety were biologically active molecules that have been widely applied in recent years in research on pesticides, particularly insecticides. In this work, a newly synthesized 2-(4-nitrophenyl)-(3,5-difluoro-pyridine-6-yl)-1,3,4-oxadiazole compound was characterized using spectroscopic techniques. The quantum chemical computations based on density functional theory were employed to investigate the molecular configuration of title compound. The modes of vibrations of the compound were identified through potential energy distribution, and the results were consistent with the experimental infrared and Raman data. Natural bond orbital assessment evaluated the significant donor-acceptor interactions within the molecule. The frontier molecular orbital analysis was performed to obtain global reactivity parameters. The molecular electrostatic potential was used to visualize the chemical reactivity and charge distribution of the molecule. From the nuclear magnetic resonance spectra, the carbon atoms bonded with nitrogen and oxygen atoms show the up-shielded peaks. The chemical implication of molecule was explained using electron localization function and localized orbital locator analysis. Moreover, the molecular docking studies performed for the newly synthesized compound revealed an efficient interaction with the acetylcholine receptor and exhibited better binding affinity than commercialized insecticides. Whilst, the physicochemical properties were assessed using the insectiPAD webtool to comprehend the insecticidal properties of title compound. Finally, the quantitative structure activity relationship study of 2-(4-nitrophenyl)-(3,5-difluoro-pyridine-6-yl)-1,3,4-oxadiazole showed higher activity (pLC50 = −1.43) against Mythimna separata, as compared to commercial insecticide avermectin (pLC50 = −1.47). These results provided that title compound could be used as a template for future insecticide investigations. [ABSTRACT FROM AUTHOR]

There are great demands of developing ultra‐narrow bandgap electron acceptors for multifunctional electronic devices, particularly semi‐transparent organic photovoltaics (OPVs) for building‐integrated applications. However, current ultra‐narrow bandgap materials applied in OPVs, primarily based on electron‐rich cores, exhibit defects of high‐lying energy levels and inferior performance. We herein proposed a novel strategy by designing the benzothiazole‐fused cyanoindone (BTC) unit with ultra‐strong electron‐withdrawing ability as the terminal to synthesize the acceptor BTC‐2. The BTC unit imparts red‐shifted absorption up to 1000 nm to BTC‐2, attributed to enhanced intramolecular charge transfer and the quinoid resonance effect. Additionally, BTC‐2 features deep‐lying energy levels with the highest occupied molecular orbital level of −5.81 eV, due to the ultra‐strong electron‐withdrawing ability of BTC. Furthermore, BTC‐2 exhibits long‐range ordering in both molecular packing and macroscopic blend morphology, resulting from shoulder‐to‐shoulder packing of two BTC units, leading to an ultra‐long exciton lifetime over 1.1 ns. These superiorities facilitated a 17.17 % efficiency in the binary OPV device with an extremely high photocurrent of 30.34 mA cm−2, representing the best performance for ultra‐narrow bandgap electron acceptors, and a record light utilization efficiency of 4.88 % in binary semi‐transparent systems. Overall, BTC is a superior building block for designing ultra‐narrow bandgap electron acceptors. [ABSTRACT FROM AUTHOR]

A series of heterobimetallic (Au⋯Ag interlocking and Au⋯Cu interlocking) [2]catenanes were studied using DFT and TD-DFT methods to explore the relationship between their structures and properties. In order to fully investigate the influence of metal type in these [2]catenanes and compare the similarities and differences between these heterobimetallic and homometallic catenanes, the results were also compared with our previously studied homometallic Au⋯Au interlocking [2]catenane molecules. The results display that the steric hindrance increases with the increase of the number of monomers, and thus the distances between the center and the edge of the rings become longer, demonstrating a trend of outward expansion. As the size of the ring becomes larger, the total weak interaction increases and shows increasingly dispersed distribution. The value of the dispersion interaction energy increases with the overgrowth of the size of molecular systems and correspondingly the energy level of the frontier orbital decreases and the energy gap becomes bigger when two hexamers interlock. Compared with the Au⋯Ag interlocking [2]catenanes, the Au⋯Cu interlocking [2]catenanes present red-shifted absorption spectra, which is consistent with their smaller energy gap. The hole–electron analysis results indicate that the S0 → S1 excitations are almost unidirectional charge transfer excitations due to the significant separation of holes and electrons, while for the high-energy excited states, local excitations occupy a dominant position. Through the study of the specific proportion of charge transfer on each fragment in the main transition process, we found that for heterometallic [2]catenanes, the Cu atom in the Au⋯Cu interlocking [2]catenanes has a greater influence on the electronic structure. As for homometallic [2]catenanes, the effects of Au atoms in the two rings are equivalent on the electronic structure. [ABSTRACT FROM AUTHOR]

Carborazine (B2C2N2H6) and borazine (B3N3H6) are isoelectronic analogues of benzene (C6H6). The aromatic character of borazine have basically reached a consensus after a long period of controversy, but the related properties of carborazine are even rarely reported. In this work, we systematically investigated the geometric structure, charge distribution, frontier molecular orbital characteristics, bonding, electronic delocalization, magnetic shielding effect, and induced ring current of carborazine and borazine, and compared the studied characteristics with those of benzene to determine the aromatic character of the two analogues. The combination of multiple properties shows that although they are isoelectronic, carborazine is evidently aromatic, while borazine only exhibits rather weak aromaticity. The C atom acting as a connecting bridge between B and N atoms in carborazine reduces the electronegativity difference on the molecular backbone and enhances the electronic delocalization over the conjugated path, which is the essence of the distinct disparity of aromaticity between carborazine and borazine. [ABSTRACT FROM AUTHOR]

This study involves the synthesis of a series of dimethyl substituted novel aurones, featuring 1,2,3‐triazole as an integral structure. All the newly synthesized compounds were thoroughly characterized using various spectroscopic tools and also subjected to computational analysis utilizing the DFT/B3LYP methodology, which involved the determination of frontier molecular orbital energy values and the computation of various quantum chemical parameters. Further their impact on cell viability and cytotoxic activity on the adenocarcinoma gastric cell line (AGS) was investigated using cell‐based MTT assay. Compounds 6d, 6o and 6p displayed significant cytotoxic activity, reducing cell viability to a greater extent with IC50 values of 9.74, 20.09, and 5.92 µM, respectively and even better than the standard chemotherapeutic drug leucovorin (IC50 = 30.8 µM). In addition, all the compounds were also screened for their extracellular enzymatic assay and through in vitro results compound 6n emerged as the efficient inhibitor of amylase (% inhibition = 51.92) and trypsin (% inhibition = 68.36), whereas an activation is observed for lipase (% activation = 269.48). In silico molecular docking was also conducted to assess the interactions between proteins and ligands, revealing the binding patterns of the synthesized compounds and the standard drug with receptor proteins. [ABSTRACT FROM AUTHOR]

Fourteen hydrazone‐Schiff base derivatives bearing 4‐bromobenzoic acid have been successfully synthesized, characterized by means of 1H‐NMR and EI‐MS spectrometry and finally evaluated for in vitro tyrosinase inhibitory activity. Among the series, five compounds 2 g, 2 k, 2 d, 2 c, and 2 n attributed potent tyrosinase inhibitors with IC50 values ranging from (IC50=6.07±0.40 μM) to (IC50=13.15±0.09 μM) surpassing the standard drug kojic acid (IC50=16.9±1.30 μM). Furthermore, the remaining compounds demonstrated significant to less inhibition. The density functional theory (DFT) study was performed to investigate various electronic properties such as geometry optimization, global reactivity parameter, frontier molecular orbitals (FMOs), molecular electrostatic potential map (MEPM), theoretical 1H‐NMR chemical shift, and nonlinear optical properties (NLO). Theoretical study shows good agreement with experimental study and NLO analysis suggest that the targeted compounds are good candidates with nonlinear optics. Furthermore, the docking studies were executed on the synthesized derivatives in order to explain the binding interface of compounds with the active sites of tyrosinase enzyme. The potent compounds observed in the current work may lead them promising candidates for future drug development. [ABSTRACT FROM AUTHOR]

AbstractThe molecular structure and spectral properties of cyclo(L-Phenylalanyl-L-Proline) dipeptide, which has several biological activities, were investigated. Firstly, conformational preference of the cyclo(L-Phenylalanyl-L-Proline) was searched and obtained lowest energy conformer of the cyclic dipeptide was then optimized using Density Functional Theory with wb97xd/6-311++G(d,p) level of theory. A detailed vibrational spectral analysis has been carried out and assignments of the fundamental modes have been proposed. The experimental vibrational wavenumbers of the investigated compound display good agreement with the computed values. The Frontier Molecular Orbitals, Molecular Electrostatic Potential and electronic transitions of the investigated compound were discussed. In addition, the 1H and 13C NMR chemical shifts of the cyclic dipeptide were calculated and the results were compared with the experimental values. Also, to evaluate the anticancer potential, molecular docking studies of cyclo(L-Phenylalanyl-L-Proline) within the ATP-binding sites of both wild type (EGFRWT; ID: 4HJO) and mutant (EGFRT790M; ID: 3W2O) Epidermal Growth Factor Receptor were performed. The results indicated that cyclo(Phe-Pro) has high binding affinities toward both EGFRWT (−6.6 kcal/mol) and EGFRT790M (−7.7 kcal/mol) receptors, thus, has good anticancer activity and also has potential to overcome drug resistance in therapy. Molecular dynamics simulations on cyclo(L-Phenylalanyl-L-Proline)-wild type complex were conducted through a 50-nanosecond timed to investigate the ligand-receptor interactions in more detail, and to determine the binding free energy accurately. The binding free energy of the cyclo(L-Phenylalanyl-L-Proline)-wild type complex was calculated to be −27.18 kcal/mol. [ABSTRACT FROM AUTHOR]

Here, we provide the synthesis process as well as theoretical and experimental research on the molecule known as 7-hydroxy-2-(3,4-dihydroxyphenyl)-3-(piperidin-4-yloxy)-4H-chromen-4-one (7THFP). Quantum mechanical calculations (QM) using several functional levels at a standard basis set have been used to calculate all QM calculations and molecular descriptors. Computational techniques were used to obtain the whole range of vibrational frequencies, IR intensity and Raman activity, all showing excellent agreement with the observed results. The molecule’s electron transport characteristics were explained by Mulliken, NBO, mapped isosurface electron density and Highest Occupied Molecular Orbitals (HOMO)-Lowest Unoccupied Molecular Orbitals (LUMO) investigations. The energy difference between the molecular orbitals (MOs) has also been anticipated. The drug candidate’s ADMET and Lipinski’s rule of five models were used to predict its physicochemical and pharmacokinetic properties, including bioactivity score, lipophilicity and toxicity profiles. The physicochemical profiles of 7THFP indicate favorable drug-likeness, bioactivity and reduced toxicity. Subsequently, molecular docking (MD) analyses were conducted to forecast the ligand’s inhibitory impact on the enzymes. The docking score estimation and in vitro analysis of the drug compound validate its anticancer activity. Lastly, the title molecule was evaluated for its proliferation and cytotoxicity effects on human MCF-7 cell lines. These investigations demonstrate that the product exhibits promising characteristics as a drug candidate and may serve as a model for further enhancement. [ABSTRACT FROM AUTHOR]

Crystalline and soluble 1D linear conjugated polymers (LCPs) have garnered considerable interest as cost‐effective and efficient metal‐free electrocatalysts for the oxygen reduction reaction (ORR) due to their high exposure of catalytic sites and ease of processing. However, difficulties remain in achieving excellent ORR performance for 1D LCPs by conventional molecular design. Herein, it is demonstrated the utilization of quinoidal units as a promising strategy to develop 1D LCPs for ORR. The incorporation of quinoidal unit not only results in polymers with strong inter‐ and intra‐molecular interactions and low‐lying LUMO (lowest unoccupied molecular orbital) energy levels, but also provides polymers with good crystallinity and commendable charge carrier mobilities. The electronic properties of these polymers are fine‐tuned through the introduction of additional heteroatoms and/or substituents in the monomers and comonomers to understand and optimize their ORR catalytic activity. Evaluation of their catalytic performances reveals a remarkable half‐wave potential and limiting current density of up to 0.74 V (vs reversible hydrogen electrod) and 7.50 mA cm−2, respectively. Notably, these performances are achieved without the addition of carbon nanomaterials as support. This study offers a new insight into the design of highly efficient metal‐free organic electrocatalysts. [ABSTRACT FROM AUTHOR]

Supramolecular polymers (SPs) formed via the stacking of π‐conjugated molecules are attractive nanomaterials because of their potential optoelectronic properties derived from the non‐covalent interaction between the π‐skeletons. Especially, SPs possessing naphthalenediimide (NDI) core units can act as superior electron acceptors due to their deep lowest unoccupied molecular orbital (LUMO). Interaction of such SP with electron donors can realize a charge transfer system, but this has not been established. Herein, we report a photoinduced electron transfer system from cesium lead bromide quantum dot (QD) as an electron donor to SP composed of cholesterol‐functionalized NDI derivatives. The supramolecular polymerization in a non‐polar solvent was analyzed in detail via microscopic and spectroscopic analyses. Upon mixing the SP with QDs, the photoluminescence intensity and lifetime of QDs decreased significantly, indicating efficient photoinduced electron transfer from QD to SP. [ABSTRACT FROM AUTHOR]

A novel Ce(III) complex with the triazole ligand 2b, which presents four H-bonded sites with amino acids of the MMP-2 receptor, was synthesized. The experimental IR and Raman spectra of this Ce(III) complex were well-interpreted based on their comparison to the theoretical scaled spectra using the scaling equations determined by two procedures and four density functional theory (DFT) levels. Therefore, the structure predicted for the synthesized Ce(III) complex was clearly characterized and confirmed. The potential antioxidant action of this complex was compared with the analogous La(III) complex, and it was found that the coordination of ligand 2b with Ce(III) improves the ligand's ability to participate in single-electron transfer (SET), as observed in the ABTS·+ assay, and this complex seems to scavenge the stable radical much more actively compared to its La(III) counterpart. Additionally, interactions with potassium superoxide and sodium hypochlorite indicate a high pro-oxidant behavior of the complex. The effects of different ligands on the geometric parameters, atomic charges, and molecular properties of the Ce(III) complex were analyzed at four DFT levels, and several relationships were clearly established. These relationships can facilitate the selection of new ligands with improved properties in the design of novel lanthanide–triazole carboxylate complexes with promising biological activity. The ligand size increase in the complexes facilitates the electronic transfer of negative charge, and the low HOMO (highest occupied molecular orbital)–LUMO (lowest unoccupied molecular orbital) energy gap indicates a large reactivity and low energy for their excitation. [ABSTRACT FROM AUTHOR]

ABSTRACT The structural, optoelectronic and charge transport properties of porphyrin and its analogues are investigated using the density functional theoretical methods. Most of the above molecules absorb in visible region with high light harvesting efficiency. The small energy gap between the frontier molecular orbitals (FMOs) suggests that porphyrin and its derivatives can be used in organic semiconductors. Electronic properties such as ionization potential, electron affinity, reorganization energy and the charge transfer integral are calculated to obtain their charge transport properties. It is revealed that porphyrin, porphyrazine and phthalocyanine act as hole transporters, whereas corrole and corrolazine act as electron transporters. [ABSTRACT FROM AUTHOR]

Despite notable advancements in cancer therapy, it remains a formidable global health challenge. The emergence of combinational treatments, particularly the integration of chemotherapy with photodynamic therapy (chemo-PDT), offers a glimmer of hope. This study introduces the development of zinc-coordinated quercetin-based self-assembled nanoparticles (ZnQ NPs) for advanced dual-mode cancer therapy. These cutting-edge ZnQ nanoparticles were synthesized in a rapid 15-minute single-step process, in stark contrast to the conventional hours or days required. Using Density Functional Theory (DFT) calculations, the optimal binding configurations of ZnQ NPs were precisely determined and further supported by band gap calculations between frontier molecular orbitals. Quercetin, a potent anticancer flavonoid, was used for the first time both as an active drug and as an organic ligand, resulting in pH-responsive nanoparticles with exceptional water dispersibility, stability, and biocompatibility. Additionally, these novel nanoparticles (NPs) were able to load chlorin e6 (Ce6), a photosensitizer known for its high singlet oxygen production, due to hydrophobic interactions within the pores. The ZnQ@Ce6 nanocomposite demonstrated remarkable Ce6 loading (19.03%) and significantly enhanced therapeutic effects, achieving a 77% cell inhibition rate under specific light conditions. This dual-functional platform, enhancing the solubility and bioavailability of Ce6 while harnessing the anticancer properties of quercetin, underscores the potential of ZnQ NPs in clinical nanomedicine, promising improved cancer treatment outcomes. [ABSTRACT FROM AUTHOR]

The development of nonfullerene acceptors (NFAs), represented by ITIC, has contributed to improving the power conversion efficiency (PCE) of organic solar cells (OSCs). Although tuning the electronic structures to reduce the exciton binding energy (Eb) is considered to promote photocharge generation, a rational molecular design for NFAs has not been established. In this study, we designed and developed two ITIC‐based NFAs bearing spiro‐substituted bithiophene or biphenyl units (named SpiroT‐DCI and SpiroF‐DCI) to tune the frontier molecular orbital (FMO) distribution of NFAs. While the highest occupied molecular orbitals (HOMOs) of SpiroF‐DCI and ITIC are delocalized in the main π‐conjugated framework, the HOMO of SpiroT‐DCI is distributed on the bithiophene unit. Reflecting this difference, SpiroT‐DCI exhibits a smaller Eb than either SpiroF‐DCI or ITIC, and exhibits greater external quantum efficiency in single‐component OSCs. Furthermore, SpiroT‐DCI shows improved PCEs for bulk‐heterojunction OSCs with a donor of PBDB‐T, compared with that of either SpiroT‐DCI or ITIC. Time‐resolved spectroscopy measurements show that the photo‐induced intermolecular charge separation is effective even in pristine SpiroT‐DCI films. This study highlights the introduction of spiro‐substituted bithiophene units that are effective in tuning the FMOs of ITIC, which is desirable for reducing the Eb and improving the PCE in OSCs. [ABSTRACT FROM AUTHOR]

Singlet fission (SF) is a photophysical process where one singlet exciton splits into two triplet excitons. To construct design guidelines for engineering directional triplet exciton migration, we investigated the SF dynamics in symmetric linear heterotrimer systems consisting of different unsubstituted or 6,13-disubstituted pentacene derivatives denoted as X/Y (X, Y: terminal and center monomer species). Time-dependent density functional theory (TDDFT) calculations clarified that the induction effects of the substituents, represented as Hammett's para-substitution coefficients σ p , correlated with both the excitation energies of S1 and T1 states, in addition to the energies of the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO). Electronic coupling calculations and quantum dynamics simulations revealed that the selectivity of spatially separated TT states for heterotrimers increased over 70%, superior to that in the homotrimer: an optimal region of the difference in σ p between the substituents of X and Y for the increase in SF rate was found. The origin of the rise in SF rate is explained by considering the quantum interference effect: reduction in structural symmetry opens new interaction paths, allowing the S1-TT mixing, which contributes to accelerating the hetero-fission between the terminal and center molecules. [ABSTRACT FROM AUTHOR]