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Exploring the organic molecular structural features and supramolecular interactions provide basis for developing stimuli-responsive organic solid-state fluorescent materials. Herein, we have synthesized methoxyphenyl-substituted carbazole-based π-conjugated derivatives (Cz-MN, Cz-ECA, Cz-CA, Cz-CAA and Cz-NBA) with different acceptor units and investigated their influence on solid-state fluorescence. All five compounds showed aggregation-induced emission (AIE) in the solid state with acceptor-dependent tunable fluorescence from 488 to 602 nm (quantum yield (Φf) = 7.2 to 1.9%). Cz-ECA exhibited blue-shifted fluorescence, whereas Cz-NBA showed red-shifted fluorescence. Cz-MN, Cz-ECA and Cz-CA revealed relatively strong solid-state fluorescence compared to Cz-CAA and Cz-NBA. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculations suggested intramolecular charge transfer (ICT) from the carbazole donor to the acceptor unit. Mechanofluorochromic studies of Cz-MN and Cz-ECA showed self-reversible fluorescence switching but the other three AIEgens did not show any stimuli–response. Single crystal structural analysis of Cz-MN, Cz-ECA and Cz-CA showed twisted molecular conformations with different intermolecular interactions. Both Cz-MN and Cz-ECA did not show any strong intermolecular interactions in the crystal lattice. In contrast, Cz-CA exhibited strong amide–amide complementary H-bonding and an extended network structure. Hence, the twisted molecular conformation and the absence of strong intermolecular interactions in Cz-MN and Cz-ECA contributed to self-reversible mechanofluorochromism (MFC). Thus, the present study is expected to provide further insight to design AIEgens with stimuli-responsive self-reversible fluorescent materials. [ABSTRACT FROM AUTHOR]

The current study reports tailoring the electronic donor structures of organic dyes to modify their optical and nonlinear optical (NLO) response properties. Five (5) tri‐phenyl amine (TPA) based Donor‐π‐Acceptor (D‐π‐A) organic dyes with the codes ICAA1, ICAA2, ICAA3, ICAA4, and ICAA5 were designed and investigated for their optical and NLO properties using quantum chemical methods. Optical and NLO properties of these dyes were studied by CAM‐B3LYP method and 6‐311G* basis set. The focus has been on the impact of adding secondary donors and shifting their substitutions at ortho (o), meta (m) and para (p) positions. Among all designed compounds, ICAA4 showed the highest amplitude of average third‐order NLO polarizability <γ>, which is calculated to be 1316 × 10−36 esu. Time‐dependent Density Functional Theory (TD‐DFT) method was used to determine how a change in the position of the donor affected the excitation energy (Eg) and NLO response properties. The findings showed that changing the position of the secondary donor results in a red shift among absorption spectra as well as the increase in their NLO responses. Complete process of intramolecular charge transfer (ICT) has been investigated in terms of different optical parameters such as frontier molecular orbitals (FMOs), molecular electrostatic potentials (MEPs), transition density matrix (TDMs), density of states (DOS), electron density difference (EDD), and natural bond orbital (NBO) analysis. Our calculations for study of ICT process indicate that p‐position of methoxy group performs better among all other positions and even it has better NLO response properties than the compound with three collective methoxy groups. The calculated Voc values of all designed molecules range from 1.09 to 1.30, all of them are positive while their ΔGinject is found to be in the range of −0.87 to −1.79 eV indicating their decent potential for photovoltaic applications. The studied optical, NLO and photovoltaic parameters illustrated that ICAA1 to ICAA5 are appropriate molecules not only for NLO applications but also for efficient photovoltaic purposes. [ABSTRACT FROM AUTHOR]

The curcuminoid class of organic compounds is very versatile which possesses applications over vast fields of science and technology. In the present investigation, we systematically designed six curcuminoid (Crmd) derivatives with symmetric and asymmetric structures, which are named as Crmd-1 to Crmd-6. We used 2,2-difluoro-4,6-divinyl-dioxaborinine moiety as a linker to design symmetric and asymmetric donor π-conjugation and acceptor configurations. Triphenylamine and triphenylborane are used as donor and acceptors which are intrinsically donor and acceptors owing to the presence of vacant p-orbital in boron and lone pair of electrons in nitrogen atoms, respectively. Density functional theory (DFT) is applied using M06/6-311G* method to calculate linear polarizability (α), and second hyperpolarizability (γ). The value of isotropic linear polarizability (αiso) and anisotropic linear polarizability (αiso) are 125.3 × 10–24 esu and 148.1 × 10–24 esu for Crmd-6, respectively. By comparative analysis, it is observed that the highest value of γ amplitude is calculated to be 6472.3 × 10–36 esu for Crmd-6. The robust increase in non-linear optical (NLO) polarizability is observed due to the asymmetric intramolecular charge transfer (ICT) and better D-π-A configuration in Crmd-6. Time dependent DFT calculations are performed to observe the origin of third-order NLO polarizabilities. Furthermore, frontier molecular orbitals, electron density difference, molecular electrostatic potential diagrams, and transition density matrix analysis demonstrate enhanced charge redistribution from the donor to the acceptor fragments. The use of modern computational tools highlights an effective ICT, which leads stronger third-order NLO response properties in designed curcuminoid derivatives. [ABSTRACT FROM AUTHOR]

The halogen substitution in an organic fluorophore exerted significant influence on the molecular organization via halogen intermolecular interactions and solid-state fluorescence. The carbazole core unit has been extensively utilized for developing optoelectronic materials because of its excellent fluorescence and phosphorescence properties. Herein, we have synthesized dihalogen substituted carbazoles (Cz-Cl, Cz-Br, Cz-I) and investigated their role in the supramolecular organization and solid-state fluorescence. Solid-state structural analysis revealed that Cz and halogen derivatives produced a herringbone structure but with varied intermolecular interactions and molecular orientation. Cz showed N–H⋯π intermolecular interactions between the amine hydrogen and middle ring of carbazole. Cz-Cl and Cz-Br also showed N–H⋯π intermolecular interactions but between the amine hydrogen and halogen decorated phenyl ring of carbazole. Cz-I showed only weak halogen–halogen and halogen–hydrogen intermolecular interactions. Cz showed strong fluorescence in solution as well as the solid-state (Φf = 55.9%). However, halogen substituted carbazole derivatives showed only solid-state fluorescence with strong reduction of fluorescence efficiency (Φf = 6.5% (Cz-Cl), 1.2% (Cz-Br)). Further, Cz-I did not show any fluorescence even in the solid-state. The significant reduction of fluorescence might be attributed to the heavy atom effect. Halogen substitution also caused varied electron density distribution in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Thus, halogen substitution influenced the molecular organization via halogen intermolecular interactions and solid-state fluorescence due to the heavy atom effect. [ABSTRACT FROM AUTHOR]

A hexaazatrinaphthylene [HAT] is a well‐known halogenated perylene diimide compound recognized for photochemical stability, high electron affinity, easy functionalization, and high conductivity. Based on density functional theory, optoelectronic and charge transport properties of HAT derivatives with electron‐donating, electron‐withdrawing, and push‐pull substituents, were investigated. The impact of substituting electron‐withdrawing groups (EWG), electron‐donating groups (EDG), and push‐pull substituents on various aspects, including molecular structure, frontier molecular orbitals, ionization energy, electron affinity, reorganization energy, crystal packing, and charge carrier mobility, is investigated. A crystal structure simulation method is employed to optimize potential arrangements of crystal packing for the molecules under examination. The presence of EWG, EDG, and push‐pull substitutions significantly affects the energy and distribution of electron density in the frontier molecular orbitals, leading to alterations in the absorption spectrum and charge transport properties. When adding various substituents to the core system, the different crystal packing motifs and varied intermolecular interactions of the examined molecules result in noticeably different transfer integrals. Due to higher hole reorganization energy and weak HOMO orbital overlapping, HAT derivative molecules exhibit better electron mobility. Among the studied molecules, HAT‐F and HAT‐F‐OCH3 molecules demonstrate better electron mobility with values of 0.49 and 2.36 cm2 V−1 s−1, respectively, and established the n‐channel characteristics. [ABSTRACT FROM AUTHOR]

We systematically study the optical and nonlinear optical (NLO) properties of various cyclopentadithiophene (CPDT) derivatives using quantum chemical calculations. The designed derivatives are classified into three classes and each class have three types of derivatives as a, b and c. For example, compounds 1a, 2a, and 3a are formed by substituting nitrophenyl at the terminal positions of 2,6-diphenyl-4 H-cyclopenta[2,1-b:3,4-b′]dithiophene at the terminal positions to design V-shaped (Λ-shaped) compounds and similar pattered were adopted for other classes. The dipole moment (µ), linear isotropic and anisotropic polarizability along with second-order and third-order NLO polarizability are computed by applying density functional theory (DFT) methods at PBE1PBE/6-311G** level of theory. Among all the derivatives, 3a and 1a shows the maximum linear isotropic (αiso) and anisotropic (αaniso) polarizability of 120.4 × 10−24 and 161.4 × 10−24 esu respectively. The noteworthy effect of incorporating different electron donor and acceptor moieties to the overall NLO polarizability is observed. The largest average second-order NLO polarizability value is observed 92.59 × 10−30 esu for system 1a. The β// amplitude of 1a is ~ 1.5 to 11 times more as compared to other derivatives. Additionally, the nonlinear anisotropy of β// amplitudes is also seen significantly larger ranging from 4.96 to 129.63 which is due to the V-shaped structure of designed compounds. While on the other hand, some compounds shows the third-order NLO polarizability amplitudes which are ranging in thousands including 4107 × 10−36, 5020 × 10−36, 5857 × 10−36, 6412 × 10−36, 6700 × 10−36 and 9057 × 10−36 esu for compounds 1b, 2b, 3a, 2a, 3b and 1a, respectively. Strikingly, the β// and <γ> amplitudes of compound 1a are ~ 14 and ~ 1242 times greater than that of standard para-nitroaniline (prototype NLO molecule), respectively, as computed at same PBE1PBE/6-311G** method. The TD-DFT calculations are also performed to see origin of larger NLO polarizabilities. The molecular electrostatic potential maps and frontier molecular orbitals are drawn to get further insight into the structure-NLO property relationship of newly designed CPDT derivatives. Hence, we considered that the current investigation will interest the researchers to further explore the optical and NLO applications of these CPDT derivatives. [ABSTRACT FROM AUTHOR]

In this paper, nonlinear optical (NLO) active single-crystal 2-amino-6-ethoxy benzothiazolium diphenylacetate (BTDPA) crystallized in an orthorhombic crystal system with non-centrosymmetric space group P212121. The thermal studies (TG–DTA and DSC) and characterization studies such as FT-IR, FT-Raman, NMR, UV–Vis–NIR, PXRD, and NLO studies (Kurtz–Perry powder method) of BTDPA crystal were recorded and investigated. Molecular geometry of BTDPA was optimized using quantum chemical computational method with M06-2X functional and 6-31G** basis set. Frontier molecular orbitals, molecular electrostatic potential, and density of states were calculated for optimized geometry to see the trend of electronic charge distributions at ground state. The TD-M06-2X method was used to calculate electronic transitions which were compared with experimental UV–Visible spectrum of BTDPA. Additionally, at molecular-level static isotropic, anisotropic linear polarizability, and third-order NLO polarizability were also calculated which were found to be 42.33 × 10–24 esu, 24.27 × 10–24 esu, and 18.95 × 10–36 esu, respectively. The current investigation of BTDPA molecule highlights good optical and nonlinear optical properties which can be of added value in the field of optoelectronic and laser applications. [ABSTRACT FROM AUTHOR]

Carboxylic acid supramolecular synthon exhibited dimer or catemer motifs in the crystal lattice depend on the substituent and other functional groups present in the structure. In general, presence of other competing functional groups produced catemer motifs, whereas unsubstituted acids showed dimer. In this manuscript, we have synthesized a new aryl ether amine-based Schiff base with carboxylic acid functionality (1) and demonstrated polymorphic structure via catemer (1a) and dimer (1 b) motifs in the solid state. In both the structure, carboxylic acid group adopted different orientation in the crystal lattice. The different H-bonding lead to modulation of optical properties that was further supported highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculation. Further the stability calculation indicates that dimer (1 b) structure was more stable by 8.54 kcal/mole relative to catemer (1a) motifs. Further, the supramolecular interactions in catemer (1a) and dimer (1 b) motifs was studied by Hirshfeld surface and fingerprint plots to gain insight and compare the different functional groups contribution for intermolecular interactions in the polymorphic crystals which clearly showed different intermolecular interactions in polymorphs. [ABSTRACT FROM AUTHOR]

In the present investigation, a variety of quinoidal oligomers with different arrangements and distinctive fused shapes of thiophene rings are studied. These quinoidal oligomers were further explored for the systematic heteroatom substitution using state-of-art quantum computational methods. The substitution of S atoms by O and N in oligomer compounds is done to see change in optical and nonlinear optical properties while moving from series 1 to series 4. The substitution of oligomer chain shows a significant effect on linear polarizability, first and second hyperpolarizabilities as calculated at M06/6-311G** level of theory. All the studied compounds showed relatively average first hyperpolarizability while reasonably large second hyperpolarizability. Among all the studied compounds, the largest second hyperpolarizability of 1003 × 10–36 esu is shown by 4c which is ~ 138 times greater than standard p-NA molecule. Interestingly, TD-DFT analysis indicates that the series 4 has larger oscillator strengths and lower transition energy values which contributes to its enlarged amplitude of second hyperpolarizability response. Furthermore, the transition density matrix, frontier molecular orbitals and molecular electrostatic potential diagrams showed that the charge transfer occurs from oligomer chain to cyanide groups and this charge transfer is highly dependent on the substitution patterns. The density of states diagrams of the selected class of compounds 4a, 4b and 4c show that 4c has significant partial contributions of oligomer chain in HOMO–LUMO orbitals. Thus, the comparative study of four series of compounds indicates not only the importance of shape and size of oligomer molecules but also indicates the importance of heteroatom substitutions to attain a vigorous second hyperpolarizability response for their potential use in optoelectronic and NLO applications. [ABSTRACT FROM AUTHOR]

We designed six 4,6-di(pentacenothiophene-2-yl)pyrimidine molecules with excellent charge transport properties. The optimization of ground-state geometries with B3LYP/6-31G** level is adopted with the help of first-principle investigations. The bridge elongation strategy was employed to strengthen intra-molecular charge transfer. The time-dependent density functional theory (TDDFT) was employed for the measurement of absorption spectra (λabs). The λabs, energy gaps (Egaps), frontier molecular orbitals (FMOs) energies, electron injection, ionization energy (IE), electron affinity (EA) along with reorganization energy (λ) values were computed. The substitution of long-chain polyacene cores as well as thiophene enhanced the EA, reduces hole/electron λ along with their IE. The λ(h), and λ(e), were compared with hole and electron transfer within mostly used compounds, like pentacene and tris(8-hydroxyquinolinato)aluminum (mer-Alq3), respectively. It is anticipated that novel designed compounds may be better to be used for hole transfer (as pentacene) and electron transfer (as mer-Alq3) compounds. These derivatives would act as productive materials that can be employed as p- and n-type semiconductors. The elongation of oligothiophene and acene cores act as excellent hole transfer materials that may be better than frequently used p-type reference compounds. These designed derivative also showed lower λ (e) values exhibited that these may be best/comparable with commonly used n-type mer-Alq3. [ABSTRACT FROM AUTHOR]

The synthesis of 1-benzyl-2-((2-Aminoethyl) amino)-5-oxopyrrolidine-3,4-diyl diacetate (boad), an oxopyrrolidine type ligand; designed to coordinate lanthanides (Eu3+ and Tb3+) to get luminescent material. The target complexes showed good photoluminescence properties, which indicate that this type of compound can be used as sensitizers having luminescence for the green (Tb3+) and red (Eu3+) emission. The obtained results revealed that sensitizer efficiency can be improved by adding ligands like acac (Eu(acac)3, which has also enhanced the luminescence quantum output and period for Eu3+ ions. The ground state geometries were developed by using density functional theory at B3LYP/6-31G** level. The charge transfer analysis and electronic properties were performed. The Europium and Terbium complexes formation with boad ligand was explored based on molecular electrostatic potential, MDC-q charges, and frontier molecular orbitals (FMOs) analysis. [ABSTRACT FROM AUTHOR]

Charge transport and electronic character of fluorophore chalcogenides 4,4-Difluoro-8-(-XC4H3)-4-bora-3a,4a-diaza-s-indacene (X = O, S, Se) (BODIPY) derivatives were examined at the molecular level. The effect of chalcogenides was investigated on the transfer integrals, electron affinity (EA), frontier molecular orbitals (FMO), ionisation energy (IE), intrinsic mobility along with reorganisation energies. The ring dissimilarities within 4,4-difluoro-8-(-XC4H3)-4-bora-3a,4a-diaza-s-indacene (X = O, 2-/3-furyl (Comp1/Comp4)); (X = S, 2-/3-thienyl (Comp2/Comp4)) and (X = Se, 2-/3-selenenyl (Comp3/Comp6)) were compared systematically. Among BODIPY chalcogenides derivatives, 2-furyl substitution is more beneficial compared with 2-thienyl, 2-selenenyl and 3-furyl as the prior moiety significantly increases intrinsic hole mobility. The –S or –Se substitution at 2- or 3- position in place of –O at equivalent position reduces the structural polarisation from neutral to cation resulting in reduced hole reorganisation energies. The doping of –S or –Se at 2-position decreases the hole transfer integral in comparison to 2-furyl-substituted derivative. The effect of chalcogen atoms on 2- or 3- position is not so significant on the HOMO/LUMO energy levels. It is expected that –O doping at 2-position in furyl is supporting p-type charge transport channel. These results demonstrated that the studied BODIPY derivatives would be efficient hole transfer materials to be used in organic semiconductor devices. [ABSTRACT FROM AUTHOR]

New cytotoxic steroidal glycoside of methanol extract from Kochia prostrata (L.) Schrad was investigated in this study. Bio-guided isolation from ethylacetate fraction of whole plant afforded steroidal glycosides named as 5-ene-dimethylcholest3-O- β -D-glucoside (Kochioside 1A1), 5-ene-methylcholest3-O- β -D-glucoside (Kochioside 2A1) and 4-ene-dimethylcholest3-O- β -D-glucoside (Kochioside 3A1). Their structures were assigned by physical and spectroscopic methods. Kochiosides 1A1–3A1 showed inhibitory potential against brine shrimp lethality bioassay with etoposide standard drug. The new steroidal glycoside kochiosides 1A1–3A1 showed inhibition values of 8.3201, 8.8205 and 8.2310 μ g/mL, respectively with LD 5 0 compared to standard etoposide LD 5 0 (7.4625 μ g/mL) drug. Moreover, six new derivatives were designed by substituting the –NH2 and –OCH3 at R1, R2 and R3 positions in the isolated compounds. Herein, various molecular descriptors, frontier molecular orbitals (FMO), electron affinity, ionization potential and molecular electrostatic potential (MEP) were carried out to understand the active sites and biological active nature of the new cytotoxic steroidal glycoside kochiosides. The effect of electron donating groups (–NH2 and –OCH3) was also investigated on the structural parameters and electronic properties in gas and solvent (DMSO) phases. The energy gap, MEP and reactivity descriptors values demonstrate that the kochioside 3A1 retains good reactivity, which is in good agreement with current experimental studies. New cytotoxic steroidal glycoside of methanol extract from Kochia prostrata (L.) Schrad was investigated. Moreover, six new derivatives were designed by substituting the –NH2 and OCH3 at R1, R2 and R3 positions. The effect of electron donating groups (–NH2 and –OCH3) were also investigated on the structural parameters and electronic properties in gas and solvent (DMSO) phases. The energy gap, molecular electrostatic potential and reactivity descriptors values demonstrate that the kochioside 3A1 retains good reactivity, which is in good agreement with current experimental studies. [ABSTRACT FROM AUTHOR]

Three novel pyrimidine based bis-uracil derivatives 1–3 were synthesized by the condensation reaction of 2-hydroxynaphthaldehyde with 6-amino-1,3-dimethylpyrimidine-2,-4(1H, 3H)-dione; 6-amino-1, 3-diethylpyrimidine-2,-4(1H, 3H)-dione, and 6-amino-1,-ethyl-3-methylpyrimidine-2,-4(1H, 3H)-dione, respectively and structurally characterized. The preliminary test of compounds was evaluated by SwissADME that can predict rapidly key parameters for a collection of molecules to support their drug discovery endeavors. Antimicrobial, photoluminescence, and molecular docking of compounds were also studied. The kinetic and thermal stabilities along with intramolecular charge transfer characters were obtained for compounds using frontier molecular orbitals, electrostatic potential diagrams as well as their orbital energies. Additionally, we applied state-of-art computational methods to assess the linear and nonlinear optical (NLO) properties of compounds at M06/6-311G** levels of theory. The third-order NLO properties of 1–3 were observed larger as compared to the standard indicating the considerable NLO character of all molecules, which may render the above derivatives as efficient candidates for NLO device fabrications. [ABSTRACT FROM AUTHOR]

Present investigation deals with an in depth study of three compounds including 4-(4-chlorophenyl)-8-methyl-2-oxo- 1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile (1), 4-(4-bromophenyl)-8-methyl-2-oxo-1,2,3,4,4a,5,6,7-octahydroquinoline-3- carbonitrile (2) and 8-methyl-2-oxo-4-(thiophen-2-yl)-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile (3) with respect to their structural, electronic, optical and charge transport properties. The ground and excited states geometries were optimized by density functional theory (DFT) and time dependent DFT, respectively. To rationalize the adopted methodology, the calculated geometrical parameters at ground state were compared with the experimental crystal structures. Several quantum chemical insights including the analysis of frontier molecular orbitals (FMOs), total/partial density of states (T/PDOS), molecular electrostatic potentials (MEP), local and global reactivity descriptors revealed that the studied compounds would be efficient multifunctional materials. The absorption wavelengths as well as their major transitions were thoroughly studied at TD-B3LYP/6-31G** level of theory. The smaller hole reorganization energies indicate that all these compounds might show better hole transport tendency. The anionic geometry relaxation of compound 2 is larger than the cationic form which leads to higher electron reorganization energy revealing the reduction of electron charge transport as compared to the hole. [ABSTRACT FROM AUTHOR]

In the present study, we report synthesis, characterization, structural and theoretical studies of two copper(II) complexes, [Cu(py)2(L1)2] (1) and [Cu(phen)(Ac)2-Cu2(Ac)4]n (2), and a nickel(II) complex, [Ni(bipy)(L)(Ac)] (3), where py = pyridine, L1 = 3,5-dichloro-2-hydroxybenzaldehyde, phen = 1,10-phenanthroline, Ac = acetate ion, bipy = 2,2'-bipyridine and HL = 4-bromo-2-(Z)-(naphthalene-2-ylimino)methyl) phenol. The new complexes were fully characterized using microanalysis, FAB-mas (m/z), FT-IR, UV-Vis and fluorescence spectra, X-band EPR spectroscopy and then by single crystal X-ray diffraction studies. X-ray studies of 1 and 3 revealed distorted octahedral geometries. Complex 2 is a coordination polymer built by an octahedral copper unit Cu(phen)(Ac)2 alternating with paddle wheel species Cu2(Ac)4, located on a crystallographic center of symmetry, where an acetate anion bridges the two crystallographic independent copper ions. The fluorescence intensities and quantum yields of 1 and 2 were found to be more compared to 3. The preliminary tests in the potential application for theoretical biological activities of compounds have also been studied. Furthermore, we also performed quantum chemical calculations to get insights into the structure-property relationships of the synthesized complexes. The quantum chemical calculations were used for theoretical calculations of linear polarizability and third-order nonlinear optical polarizability (γ) for 1, 2 and 3. Besides this, the theoretical calculations, including the analysis of frontier molecular orbitals and electrostatic potential diagrams, are used to highlight the theoretical aspects of metal to ligand charge transfer (MLCT) processes in the studied complexes. [ABSTRACT FROM AUTHOR]

Herein, we reported the imino phosphonate compounds: (4‐methoxy‐benzylidene‐amino‐phenyl‐methyl‐phosphonic acid diethyl ester (MBPDE), 4‐hydroxy‐benzylidene‐amino‐phenyl‐methyl‐phosphonic acid diethyl ester (HBPDE) and 4‐hydroxy‐3‐methoxy‐benzylidene‐amino‐phenyl‐methyl‐phosphonic acid diethyl ester (HMBPD) form the chemical reaction of diethyl (α‐amino benzyl)phosphonate hydrochloride and substituted benzaldehyde. These compounds were characterized by various spectroscopic techniques: FT‐IR, Mass, UV–VIS, 1H NMR and 13 C NMR. Additionally, the optimized molecular structures, FT‐IR, natural bond orbitals (NBOs), frontier molecular orbitals (FMOs), non‐linear optical (NLO) properties were calculated by the density functional theory (DFT) using the B3LYP functional with the 6–311+G(d,p) basis set. Moreover, UV–Visible spectrum of MBPDE, HBPDE and HMBPD were predicted in different solvents using the time dependent TD‐DFT [B3LYP/6‐311+G(d,p)] method using Polarizable Continuum Model (PCM). The non‐linear optical (NLO) properties were calculated by M06 functional with the 6–311+G(d,p) basis set. A synergistic relationship is observed between the experimental and theoretical findings. NBO analysis provided insights about the stability and charge delocalization of the entitled molecules. The global reactivity descriptors were achieved through HOMO‐LUMO energies. The efficiency of the entitled molecules concerning charge transfer and participation in diverse chemical reactivities were figured out perceptibly by applying the frontier molecular orbitals (FMOs) analysis. The average polarizability <α> values: 277.184, 261.332 and 280.254 a.u. of the MBPDE, HBPDE and HMBPD were determined respectively. The total first hyperpolarizability (βtot) values of the MBPDE, HBPDE and HMBPD were also obtained to be 992.900, 781.527 and 1107.526 a.u. respectively. The compound HMBPD comprising of higher magnitude of average polarizability and the total first hyperpolarizability (βtot) values than MBPDE and HBPDE molecules. Moreover, NLO properties of urea molecule were found smaller in comparison to the MBPDE, HBPDE and HMBPD. The medicinal importances of these novel compounds as well as its contribution towards nonlinear optical field are our future targets. [ABSTRACT FROM AUTHOR]

In the present investigation, for the first time, we have performed a thorough study about different functionals and basis sets for linear and nonlinear optical (NLO) properties of para-nitroaniline (p -NA), which is considered as proto-type NLO molecule, among organic NLO materials. There is a dire need of such data base for p -NA because many investigators are using such values of p -NA for comparative analysis. A range of different functionals including HF, BLYP, PW91, PBE, B3LYP, M06, M06-2X, PBE0, BHandHLYP, CAM-B3LYP, LC-BLYP, and B3LYP-D3 are applied in conjugation with several commonly basis sets such as 6-31G*, 6-311G*, 6-311G**, 6-311+G**, cc-pVDZ, and cc-pVTZ. A variety of functional and basis sets combinations are calculated and graphically compared with each other. The calculated total dipole moment for the p -NA is found to be 6.79 D which is quite closer to experimentally determined value. The lowest calculated value for linear isotropic polarizability at HF/6-31G* level of theory is 1 1. 7 4 × 1 0 − 2 4 esu while higher values observed with remaining all methods especially 14% polarizability increases in presence of basis set with diffuse functions and similar trend of variation is also observed in linear anisotropic polarizability. Similarly, the calculated value of frequency dependent second-order polarizability is found to be 9. 5 9 × 1 0 − 3 0 esu at PBE0/6-311+G** level of theory which is quite closer to experimental value of 9. 6 × 1 0 − 3 0 esu. A comparison between the calculated and experimental results shows good agreement among geometries, dipole moments and NLO polarizabilities for p -NA. Moreover, the frontier molecular orbital (FMO) and electron density difference map (EDDM) analysis along with density of state (DOS) plots are also presented to get more physical intuitions into the structure–property relationship and electronic communications between terminal accepter and donor groups through π -conjugation. The present investigation provides benchmark data including various commonly used functionals and basis sets for the calculation of NLO properties of p -NA. Thus, the present investigation will put straight several future studies when it comes to comparative NLO study of organic materials. • The present investigation provides benchmark data including various commonly used functionals and basis sets for the calculation of NLO properties of para-nitroaniline. • Additionally, we explore the electronic communications between terminal accepter and donor groups through π-conjugation in p-NA. [ABSTRACT FROM AUTHOR]

The structural, electro-optical and charge-transport properties of compound trans -3-(3,4-dimethoxyphenyl)-2-(4-nitrophenyl)prop-2-enenitrile (DMNPN) were studied using quantum chemical methods. The neutral, cation and anion molecular geometries were optimized in the ground state using density functional theory (DFT) at the restricted and unrestricted B3LYP/6-31G** level of theory. The excited state geometries were optimized by applying time-dependent DFT at the TD-B3LYP/6-31G** level of theory. The absorption and fluorescence wavelengths were calculated at the TD-CAM-B3LYP/6-31G** and TD-LC-BLYP/6-31G** levels of theory. The distribution pattern of the charge densities on the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) are discussed. Intramolecular charge transfer was observed from the dimethoxyphenyl to (nitrophenyl)prop-2-enenitrile moieties. The detailed charge-transport behavior of the DMNPN molecule is investigated based on its ionization potential, electron affinity, hole and electron reorganization energies, hole and electron-transfer integrals, and hole and electron intrinsic mobilities. The total/partial densities of states and structure–property relationship are discussed in detail. The higher computed hole intrinsic mobility than electron intrinsic mobility reveals that DMNPN is an efficient hole-transport material. [ABSTRACT FROM AUTHOR]

The charge transport and optoelectronic nature of semiconductor materials are important to understand their potential use in numerous semiconductor device applications. Here, diverse functional properties of Schiff base Ni(II), Cu(II) and Zn(II) complexes at molecular and solid-state bulk scales have been explored. The effect of metal substitution in Schiff based complexes has been studied at bulk level with respect to optoelectronic properties, and at isolated molecular level (frontier molecular orbitals, electron affinity, ionization potential, reorganization energy, and transfer integrals). The Zn+2 metal substitution in place of Ni+2 or Cu+2 lead to decrease the electron and hole reorganization energy values ultimately boost the hole intrinsic mobility two times higher magnitude while one and four times higher magnitude electron intrinsic mobility for Zn-comple×3 than Ni-complex1, and Cu-complex2, respectively. The effect of –COOH, –CN and –NO 2 on the frontier molecular orbitals, energy gap, reorganization energy, ionization potential, and electron affinity has been explored on isolated molecules of Ni-complex1, Cu-complex2 and Zn-complex3 as well. The intrinsic mobility and electro-optical properties explored that Ni-complex1, Cu-complex2 and Zn-complex3 as well as their derivatives would be proficient contenders for semiconductor and optoelectronic devices applications. Image 1 [ABSTRACT FROM AUTHOR]

[Display omitted] • Ladder-shape 7[helicene] derivatives were designed for efficient NLO response. • A larger NLO for [7]HC-5 is attributed to its lowest transition energy of 3.31 eV. • Unlike PCM solvation method, the gas and explicit salvation methods show good agreements. • Frequency-dependent γ values revealed that derivatives are suitable for wide range of frequency. • For photovoltaic applications, the V oc and ΔG reg for [7]HC-5 are found to be 2.71 and 0.06 eV. Researchers in materials science are greatly fascinated by helicene chemistry due to its excellent optical and structural properties. In this work, we introduced symmetrical substitution of donor and acceptor groups on the [7]helicene ([7]HC-1 to [7]HC-5). DFT analysis is used to explore nonlinear optical (NLO) response for designed compounds. For [7]HC-5 , the linear isotropic (α iso) and anisotropic polarizability (α aniso) are 31.59 × 10−24 esu and 59.86 × 10−24 esu, respectively. [7]HC-5 has the highest average third-order NLO polarizability (<γ>) of 47.24 × 10−36 esu which is approximately six times greater than that of para -nitroaniline, a well-known prototype NLO molecule. The effect of implicit and explicit solvents on <γ> and α iso of three selected compounds ([7]HC-1 , [7]HC-3 , and [7]HC-5) is also evaluated. As compared to explicit and gas phase methods, PCM model predicts an overestimation by an increment of ∼ 4-5 times for selected compounds. TD-DFT calculations show a higher transition dipole moment (4.24) and a lower transition energy (3.414 eV) for [7]HC-5. The higher NLO response is explained based on frontier molecular orbitals (FMOs), electron density difference (EDD), and molecular electrostatic potentials (MEPs). There is a red shift for studied compounds based on UV-visible results. The C-N stretching at 1372 cm-1 for [7]HC-5 indicates the presence of -N(CH 3) 2. Additionally, we studied photovoltaic parameters and found that [7]HC-5 has the maximum open circuit voltage and the lowest dye regeneration of 2.71 eV and 0.06 eV, respectively. [ABSTRACT FROM AUTHOR]

In this study, we conducted a comparative quantum computational investigation about carbazole/borole derivatives to understand how different configurations like linear and bent, and terminal groups can affect their linear and second hyperpolarizability properties. The goal was to compare the optical and NLO response properties, photovoltaic parameters and charge transfer properties of these linear/bent configurations. Among all the designed compounds the linear compounds exhibited larger linear isotropic and anisotropic polarizability and second hyperpolarizability amplitudes (γ) compared to the bent compounds. The highest values of isotropic polarizability of Py-1L and Py-2L are calculated to be 109.0 × 10–24 esu and 103.9 × 10–24 esu, respectively. Notably, linear configurations Py-1L and Py-2L achieved the γ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\left\langle \gamma \right\rangle$$\end{document} amplitudes as high as 840.1 × 10−36 esu and 776.9 × 10−36 esu. When compared to the prototype para-nitroaniline (p-NA) molecule, these amplitudes are found to be ~ 115 times and ~ 113 times larger than p-NA as calculated at the same level of theory. Moreover, TD-DFT calculations also revealed that linear configuration gave better NLO response due to their higher oscillator strengths, dipole moment changes between ground and excited states and lower transition energy values among all the designed compounds. Frontier molecular orbitals, molecular electrostatic potential map, electron density difference and natural bond orbitals analysis indicated that more efficient intramolecular charge transfer in linear configuration, leading to high NLO response than bent configuration. The highest light harvesting efficiencies have been exhibited by Py-1L and Py-2L, with values of 0.928 eV and 0.903 eV, respectively. Overall, the current systematic comparison of NLO polarizabilities and other electronic properties emphasized the importance of configuration-based designs for achieving high performance NLO response properties in the designed compounds. [ABSTRACT FROM AUTHOR]

Nonlinear optical (NLO) response materials are among the smartest materials of the era and are employed to modulate the phase and frequency of the laser. The present study presents a quantum chemical framework for tailoring nitrogen/boron doped derivatives of Dihydrodibenzo [ de , op ]pentacene through terminal and central core modifications. The derivatives of these compounds have been designed by introducing various π-conjugated connectors as well as B/N heteroatoms in the phenalene rings. Density functional theory (DFT) methods are used to optimize the ground state molecular geometries of designed compounds, represented as 1 to 4 (phenalene derivatives) and 1-BN to 4-BN (B/N doped phenalene derivatives) at the M06-2X/6-311G* level of theory. The highest value of 116.9 × 10−24 esu and 240.2 × 10−24 esu for isotropic and anisotropic linear polarizability is shown by compound 4. Among the designed compounds, 4-BN has achieved the highest γ amplitude of 1858 × 10−36 esu owing to its unique molecular structural design. Further analysis of electronic parameters, such as electron density difference (EDD) maps, the density of states, electrostatic potentials, transition density matrix (TDM) analysis, and frontier molecular orbitals analysis (FMOs), demonstrated the more effective intramolecular charge transfer (ICT) for the best compounds, resulting in a good NLO response. The compounds were also analyzed for their potential in photovoltaic applications based on factors such as open circuit voltage values determined to be between (0.14 eV and 1.82 eV), and light harvesting efficiency (0.425–0.909). • A computational framework is proposed by tailoring nitrogen/boron atoms in dihydrodibenzo-pentacene. • The designed compounds showed great variation of optical and NLO properties. • Compound 4-BN has achieved the highest γ amplitude of 1858 × 10−36 esu owing to its tailored push-pull design. • Calculated open circuit voltage observed between 0.14 eV and 1.82 eV, and. • Computed light harvesting efficiency is found from 0.425 to 0.909 for newly designed compounds. [ABSTRACT FROM AUTHOR]

Buckminsterfullerene is hard to study experimentally and computationally owing to its unique reactivity and larger molecular size, respectively. The whole C60 fullerene molecule consists of two types of chemical bonds i.e. hexagon-hexagon bonds and hexagon-pentagon bonds. A series of heterofullerenes (C 58 hh BN -C 58 hp BN) was designed by substitution in C60 fullerene with nitrogen (N) and boron (B) at the hexagon-hexagon bond and hexagon-pentagon bond positions. Quantum chemical methods were employed to examine the structural and optoelectronic characteristics of the designed compounds as compared to parent C60. The average polarizability measurements shown that the linear response of the C58hp BB compound (α iso = 116.7 × 10−24 esu, α aniso = 10.56 × 10−24 esu) is dominant. Among all designed compounds, a change in hexagon-pentagon bonds is seen as more effective for tuning the NLO response properties. For instance, C58hp BB and C 58 hp NN showed the larger <γ> response of 164.5 × 10−36 and 172.5 × 10−36 esu indicating greater potential for NLO materials. A number of techniques such as natural bond orbitals (NBOs), molecular electrostatic potential (MEPs), frontier molecular orbitals (FMOs) and absorption spectra were used to investigate the optoelectronic properties. The maximum absorption of molecules are found in between 569 and 800 nm. According to FMO analysis, C58hp BB and C 58 hp NN have smaller energy gaps (0.97 eV and 1.47 eV) and better intramolecular charge transfer. The current study evokes the aspect of hexagon-hexagon bond and hexagon-pentagon bond modification for efficient dopped buckminsterfullerene. [Display omitted] [ABSTRACT FROM AUTHOR]

The benzoxadiazole class of organic compounds demonstrates exceptional versatility, particularly in the realm of nonlinear optical (NLO) materials, where their unique properties find impactful applications. In the present study, we have focused on systematically designed six benzoxadiazole (BDZ) derivatives named as BDZ-1 to BDZ-6 by using 2,3,1-benzoxadiazole as a central core/π-spacer between the donor and acceptor. Triphenylamine and triphenylborane are used as donor and acceptor in all derivatives with addition of nitro and methoxy group as substitutions. B3LYP/6-311G* method of density functional theory (DFT) is employed for optimization of purposed systems while M06/6-311G* is used to check the NLO properties. The isotropic polarizability (α iso) and anisotropic polarizability (α aniso) of BDZ-6 , were found to be 110.1 × 10−24 esu and 106.3 × 10−24 esu, respectively. Among our designed compounds, the BDZ-6 exhibits the highest third-order NLO polarizability, which was found to be 5954.8 × 10−36 esu corresponding to lowest transition energy of 2.00 eV. Additionally, frontier molecular orbitals (FMOs), molecular electrostatic potential maps (MEPs), electron difference density maps (EDD) and UV–Vis analysis were performed. BDZ-6 shows minimum energy gap of 2.24 eV, while it shows maximum absorption at 620 nm. The density of states (DOS) analysis reveals distinct electronic contributions of various fragments in the formation of HOMO and LUMO orbitals resulting in efficient intramolecular charge transfer (ICT). Photovoltaic findings revealed that BDZ-4 have maximum open circuit voltage of 1.70 eV with minimum dye regeneration value (0.30 eV). Our findings shed light on the design and development of novel NLO materials with BDZ derivatives. [Display omitted] • Enhancement of ICT by electron withdrawing substitution on acceptor and electron donating on donor. • Minimum band gap (2.24eV) between HOMO and LUMO for BDZ-6. • BDZ-6 shows ∼817 times larger value (5954.8 × 10−36 esu) for <γ> than p-NA (prototype NLOphore). • EDD, MEPs, TDM and DOS calculations also illustrates intramolecular charge transfer. • BDZ-4 had the highest V oc value of 1.70 and the lowest ΔG reg value of 0.30 eV. [ABSTRACT FROM AUTHOR]

• Tricyclic 1 H -benzo[ f ]chromene-2-carbothioamides were synthesized as potential anticancer agents. • The cytotoxic activity was tested against MCF-7, HepG-2 and PC-3 cell lines. • Various molecular descriptors, frontier molecular orbitals, Mulliken analysis and electronic properties were studied. • The energy gaps, reactivity descriptors values and molecular docking of the target compounds were discuses. Reaction of 7‑methoxy-2-naphthol with appropriate aromatic aldehydes and 2-cyano-ethanethioamide provided the corresponding 3-amino-1-aryl-9‑methoxy-1 H -benzo[ f ]chromene-2-carbothioamide. The structures of these compounds were established on the basis of IR, 1H NMR, 13C NMR, MS data and elemental analysis. Furthermore, the anti-proliferative properties were evaluated against the human cancer cell lines MCF-7, HepG-2 and PC-3 in comparison to the positive controls Vinblastine and Doxorubicin, employing the viability assay. The obtained results confirmed that some of the tested molecules revealed strong and selective cytotoxic activities against the three cancer cell lines. Moreover, various molecular descriptors, frontier molecular orbitals (FMO), Mulliken analysis and electronic properties were studied to probe the biological activity behavior of the synthesized 1 H -benzo[ f ]chromene-2-carbothioamide derivatives. The effect of electron withdrawing groups (EWGs) and electron donating groups (EDGs) was also explored on the structural parameters and electronic nature of compounds. The energy gaps, reactivity descriptors values and molecular docking studies exhibited that some 1 H -benzo[ f ]chromene-2-carbothioamide derivatives would be active biological compounds. [ABSTRACT FROM AUTHOR]

• Optoelectronic properties of phenylimidazo-pyridine derivatives are analysed at molecular and bulk scales. • Effect of indol, phenyl and anthracenyl on properties of interests was examined. • Hybrid functionals are accurate to reproduce experimental λ abs and λ emi than LC. • The n- or p-type charge transport nature has been explored. • FMOs, IP, EA, intrinsic mobility, DOS, dielectric constant displayed them as multifunctional materials. Various optoelectronic and charge transfer properties of 3-(1H-indol-3-yl)-1-phenylimidazo[1,5-a]pyridine (Comp 1), 1,3-diphenylimidazo[1,5-a]pyridine (Comp 2), and 3-(Anthracen-9-yl)-1-phenylimidazo[1,5-a]pyridine (Comp 3) have been explored at the molecular and solid state bulk level. The absorption and emission spectra (λ abs and λ emi) were calculated by time domain B3LYP/6-311G*, CAM-B3LYP/6-311G*, LC-BLYP/6-311G* and PBE0/6-311G* levels. The hybrid functionals B3LYP and PBE0 successfully reproduced experimental λ abs and λ emi more accurately than the long-range corrected functionals. Effect of indol, phenyl and anthracenyl moieties on various properties of interests has been explored. The indol and phenyl units lead to smaller hole reorganization energies and greater transfer integrals resulting superior hole intrinsic mobility for Comps 1 and 2. The substitution of anthracenyl moiety at phenylimidazo[1,5-a]pyridine core increase the electron affinity and electron transfer integrals while decrease the electron reorganization energy. The n- or p-type charge transfer nature of Comp 3 or Comps 1 and 2 has been explored, respectively. The frontier molecular orbitals, ionization potential, electron affinity, reorganization energy, transfer integral, intrinsic mobility, density of states, dielectric constant, extinction coefficient, refractive indices, reflectivity and conductivity shown that imidazo[1,5-a]pyridine derivatives would be efficient materials to be used in multifunctional organic semiconductor devices. [ABSTRACT FROM AUTHOR]

• Quantum chemical calculations on performed on few oxazole compounds using. • Band gap, local softness values have been procured for different solvents. • Chemical structure and reactivity, topological analyses were carried out. • Solvation effects on UV–Visible spectrum were inspected using the TD-DFT system. • Optical properties and charge transport nature of the compounds were explored. The ground state geometries of oxazole compounds, i.e. , 3,5-Bis-(4-chloro-phenyl)-7a-methyl-dihydro-oxazolo[3,4-c]oxazole (Compound 1) and 3,5-Bis-(4-methoxy-phenyl)-7a-methyl-dihydro-oxazolo[3,4-c]oxazole (Compound 2) were optimized using Density functional theory employing B3LYP/6-31G++ level for comparing the geometric parameters (torsion angles, bond angles & bond lengths) with the X-ray crystallographic information. We explored the charge transport nature, wave functional properties, optical and electronic properties of both the oxazoles. The computed geometric parameters are rational to the experimental data. The time-domain TD - B3LYP/6-31G++ & the B3LYP/6-31G++ levels were used to reveal the electronic characteristics and absorption wavelength. Intra-molecular charge transfer was perceived in studied compounds. The IEFPCM (Integral Equation Formalism Polarizable Continuum Model) model was used to calculate the solvation UV spectrum. The effect of various solvents (acetone, acetonitrile, DMF(Dimethylformamide), DMSO (Dimethyl sulfoxide) and methanol) was examined on the excitation energies but solvent polarity has no discernible impact on the wavelengths of absorption. From HOMO-LUMO (Highest Occupied Molecular Orbital – Lowest Unoccupied Molecular Orbital) orbitals with various solvent molecules, band gap energies with the solvation effect are determined. Additionally, through the use of topological analytics like RDG (Reduced Density Gradient), ELF (Electron Localisation Function) & LOL (Localised Orbital Locator), the energy concentration of electrons was elucidated. Furthermore, the outcome of electron-donating cluster (–OCH 3) and electron-withdrawing cluster (–Cl) was studied on open-circuit voltage, bandgap alignment, electron coupling constants, excitons dissociation values, ΔGinject – electron injection, LHE-Light Harvesting Efficiency and electron coupling constants (|V RP |). [ABSTRACT FROM AUTHOR]

• MQSA single crystal was grown by slow solvent evaporation solution growth method. • MQSA crystallized into monoclinic crystal system with P21/n space group. • A detailed description of the optical behavior was furnished utilizing UV-Vis-NIR transmittance studies. • Hirshfeld analysis gave a graphic depiction of the donor-accepter system and intermolecular interactions. • Nonlinear optical properties of the crystal MQSA was explored. 2,3-dimethylquinoxalinum-5-sulphosalicylate (MQSA) was synthesized and grown into single crystals by slowly evaporating the solvent in methanol at room temperature. According to the lattice parameters found by the SCXRD analysis method (a = 8.8031 (17) Å, b = 17.768(3) Å, c = 10.7979(16) and α = γ = 90°, β = 90.611 (7) °), the crystal belongs to monoclinic crystal system with the P21/n space group. Moreover, powder X-ray diffraction investigation supported the crystalline nature. The compound's UV–Vis spectra exhibited a CT-band with a wavelength maximum of 372 nm, as well as its NIR spectra revealed good optical transmittance in the visible region with a low cut-off wavelength of 376 nm and an optical band gap of 5.12 eV. Dual emission bands at 418 and 484 nm are observed in the PL emission spectra. The synthesized crystal was examined using FT-IR, FT-Raman, and NMR spectral methods. The crystal is thermally stable up to 274 °C, furthermore, TG-DTA and DSC methods were employed to study the degradation process. The second and third-order NLO efficiencies of the crystal was analyzed by Kurtz-Perry powder and Z-scan methods, respectively. The single crystal of MQSA is further studied through Hirshfeld surface analysis, fingerprint plots, and crystal voids analysis to understand the intermoleculiar interactions and individual atomic arrangements inside the crystal. The H ... H and O ... H/H ... O interactions are greatly aided by crystal structure. Additionally, the quantum computational methods were used to assess several molecular level electronic properties, including molecular orbitals, molecular electrostatic potentials maps, linear polarizability and static third-order nonlinear optical (NLO) polarizability, which is a molecular-level NLO response property. The isotropic linear polarizability and NLO polarizability of MQSA are 29.99 × 10−24 esu and 28.45 × 10−36 esu, respectively, in the M06–2X/6–311G* method, which demonstrates the decent potential of the synthesized crystal for its use as NLO materials. Furthermore, the frontier molecular orbitals, molecular electrostatic potentials, and UV–Visible spectrum were calculated and discussed. [ABSTRACT FROM AUTHOR]

It is well-known that π-conjugation plays an important role to tune the nonlinear optical (NLO) response of donor-π-conjugated-acceptor compounds. Fullerenes (C 60) are one of a few compounds who are abounded with π-conjugation and perhaps are the largest π-conjugation compounds. In the present study, we systematically designed C 60 derivatives (2 (fulleropyrrolidine) and 2a-2c (fulleropyrrolidine tetrathiafulvalene derivatives where 2a , 2b and 2c are with n = 0, n = 1 and n = 2) through the use of pyrrolidine and tetrathiafulvalene moieties. We applied density functional theory (DFT) methods to calculate their respective geometrical structures, electronic properties, linear and nonlinear optical response properties along with their respective UV–Visible spectra using CAM-B3LYP functional and 6-31G* basis set. The isotropic polarizability (α iso) and anisotropic polarizability (α aniso) of 2c was found to be 131.52 × 10-24 and 47.01 × 10-24 esu, respectively. Amongst our designed compounds, the maximum second-order nonlinear optical polarizability amplitude (β //) of 2c was found to be 15.69 × 10-30 esu. Interestingly, 2c shows the highest third-order nonlinear polarizability amplitude <γ> of 284.29 × 10-36 esu that is about three times higher than parent compound 1. Additionally, frontier molecular orbitals (FMOs), molecular electrostatic potential maps (MEPs), transition density matrix (TDM) analysis indicate more effective charge redistribution from donor moiety to acceptor fragments. The density of states (DOS) diagrams reveal distinct electronic contributions of various fragments in the formation of HOMO and LUMO orbitals resulting in efficient intramolecular charge transfer (ICT) and robust third-order NLO response properties of functionalized fullerene derivatives. The current study may arouse the attention of the scientific society to utilize the extensive π-conjugation of functionalized fullerenes for designing efficient NLO materials. [Display omitted] • The most abundantly π-conjugated fullerene C 60 is functionalized for NLO properties. • Systematically C 60 derivatives are designed by pyrrolidine and tetrathiafulvalene moieties. • Geometries, electronic and NLO response properties are explored by DFT methods. • The FMOs, MEPs and TDM analyses indicate effective charge transfer characteristics. • Robust third-order NLO response is found in functionalized fullerene derivatives. [ABSTRACT FROM AUTHOR]

• Electronic and charge transport nature of 10-(1,3-Dithiol-2-ylidene)anthracene based OSMs was explored. • Effect of bridge and anchoring group was probed on intrinsic mobility. • p - or n -type charge transport ability was systematically probed. • 3,4-ethylenedioxythiophene bridge would be decent to design p -type materials. • Dicyanovinylene might be a good for designing n -type semiconductors. Electronic and charge transport nature of 10-(1,3-Dithiol-2-ylidene)anthracene based organic semiconductor materials (OSMs) have been explored at the molecular level. Effect of phenyl and 3,4-ethylenedioxythiophene of conjugated π-bridge and electron anchoring groups (−CHO and dicyanovinylene) was explored on various properties. The dicyanovinylene group lead to diminish electron reorganization energies while 3,4-ethylenedioxythiophene moiety enhance the hole transfer integrals. The dicyanovinylene groups along with 3,4-ethylenedioxythiophene moiety is favouring to reduce the HOMO and LUMO energy levels as well as their energy gap. The 3,4-ethylenedioxythiophene as bridge in OSMs would be decent to design p -type semiconductors. It is anticipated that dicyanovinylene as anchoring group might be a good approach for designing n -type semiconductors. The p - or n -type charge transport ability of anthracene derivatives was probed here. The transfer integrals, frontier molecular orbitals (FMO), ionization energy (IE), electron affinity (EA), reorganization energy, and intrinsic mobility showed that anthracene based derivatives might be proficient competitors to be applied in semiconductor devices. [ABSTRACT FROM AUTHOR]

The present study explores a series of novel donor-π-acceptor (D-π-A) molecules containing 4,4′-dimethyldiphenylamine moiety as donor, 4,4′-dinitrodiphenylborane as acceptor while different π-bridges as efficient linkers between them, which comprises of (− HC CH −) n , (− Ph −) n and (− Ph ̶ HC CH −) n combinations for compounds in series 1, 2 and 3, respectively. Quantum chemical computations are applied to calculate the linear polarizability (α), first (β) and second (γ) hyperpolarizabilities. A comparative analysis is performed considering an increase of NLO polarizabilities as a function of different π-linkers. Among the investigated compounds, 3c shows the largest first and second hyperpolarizabilities of 1378 × 10−30 and 34971 × 10−36 esu, respectively. Interestingly, an increase in NLO polarizability is observed by modifying the π-conjugated bridges and the largest NLO polarizability is observed for series 3 possessing (Ph ̶ HC CH −) n π-linker which is found due to its lower transition energy and higher oscillator strengths. Furthermore, TD-DFT investigations, frontier molecular orbitals (FMOs) and electron density difference (EDD) maps analysis have shown a more efficient intramolecular charge transfer character from donor to acceptor moieties through (Ph ̶ HC CH −) n π-linkers. The density of states (DOS) maps are showing explicit contributions of electronic states from different fragments of a molecular system where the partial contributions of (Ph ̶ HC CH −) n π-linkers is seen significant in HOMO-LUMO orbitals of all the systems in series number 3. Thus, we believe that our study will highlight the importance of different D-π-A chromophores having variant types of π-conjugation cores as discussed in the present investigation. Schematic and graphical description of the designed D-π-A molecules. Image 1 • Three series of novel D-π-A molecules consisting of (HC=CH) n , (Ph) n and (Ph ̶ HC=CH) n combinations • The NLO polarizabilities are calculated using DFT methods. • All the designed series of compounds show reasonably larger NLO responses. • A structure-NLO property relationship is examined using TD-DFT, FMOs and EDD maps. [ABSTRACT FROM AUTHOR]

A new organic,1-methylpiperazine-1,4-diium bis(hydrogen oxalate) (compound 1) has been synthesized at room temperature. This compound was subject to various characterization studies such as elemental analysis, powder X-ray diffraction, FTIR, UV–Vis and NMR spectroscopy. The structure of the crystal was confirmed by powder X-ray diffraction analysis. The 13C CP-MASNMR spectrum confirms the results predicted by X-ray diffraction. The Hirshfeld surface analysis and fingerprint plot of the compound has been presented to explore the nature of non-covalent interactions and their relative contributions in building the solid-state architecture. Furthermore, the density functional theory (DFT) methods were used to explore the optical and nonlinear optical (NLO) properties of compound 1. The calculated isotropic (α iso) and anisotropic (α aniso) linear polarizabilities are found to be28.42 × 10−24 esu and 4.81 × 10−24 esu, respectively. While the average third-order NLO polarizability <γ>of compound 1 is found to be 40.64 × 10−36 esu at M06/6-31 + G∗ level of theory. A comparison of <γ> amplitude of the studied compound with a prototype NLO molecule of para -Nitroaniline (7.41 × 10−36 esu) showed that <γ> amplitude of compound 1 is ∼5 times larger as compared to that of p -NA. Moreover, the frontier molecular orbitals, molecular electrostatic potential maps are drawn to get several structure-property insights for compound 1. Image 1 • The title compound was synthesized at room temperature. • The compound was characterized by powder X-ray diffraction, IR, NMR and UV–visible. • The non-covalent contacts were analyzed by Hirshfeld surface. • The density functional theory (DFT) methods were used to explore the optical and nonlinear optical properties. [ABSTRACT FROM AUTHOR]

• Phytochemical investigations from ethanolic extract of Oxalis corniculata L. • Bio-guided fractionation showed high phenolic and flavonoid contents. • Significant carbonic anhydrase, cholinesterase (AChE, BChE) inhibitions were probed. • The electronic properties, molecular descriptors and Hirshfeld charges were studied. Phytochemical investigations of Oxalis corniculata L. shown the existence of biologically active secondary metabolites like phenols, flavanoids, alkaloids, tannins, triterpenes, sterols, and volatile oils. In this work, ethanolic extract of Oxalis corniculata L. was prepared to explore the carbonic anhydrase and cholinesterase inhibitory activities against epilepsy and anti-Alzheimer's disease (AD) potential. Upon fractionation, chloroform and ethyl acetate fractions showed high phenolic (168.56 and 171.11 μ g ascorbic acid/g extract) and flavonoid contents (115.72 and 99.35 μ g (+)-catechin/g extract), respectively and were the most active ones against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carbonic anhydrase inhibition. The bioactivity-guided isolation from chloroform and ethyl acetate extract of Oxalis corniculata afforded nine flavonoids. The newly isolated flavonoid (1) and eight source compounds 2–9 screened by cholinesterase (AChE and BChE) and carbonic anhydrase-II (CA-II) inhibitory assays. Carbonic anhydrase inhibition rate for compounds 1–9 ranged 65.21–90.82 with the IC 50 17.11–25.18, compared with reference acetazolamide. Cholinesterase (AChE and BChE) inhibitory potential (49.52 and 29.12 μ g/mL) of newly isolated compound 1 whereas compounds 3 , 5 , 8 and 9 showed considerable significant inhibition potential using standard inhibitor serine. Moreover, the ground state geometries of all the nine compounds along with positive drugs were optimized by Density functional theory (DFT) at B3LYP/TZ2P level to explore the electronic properties and active sites. The effect of substituents on the molecular descriptors, frontier molecular orbitals, molecular electrostatic potential and Hirshfeld charges was explored. [ABSTRACT FROM AUTHOR]

Herein, two new thiazole derivatives: ethyl2-(2-benzylidenehydrazinyl)thiazole-4-carboxylate (3) and ethyl2-(2-(2-hydroxybenzylidene)hydrazinyl)thiazole-4-carboxylate (4) were synthesized by cyclization of 1-benzylidenethiosemicarbazide with ethyl bromopyruvate. The synthesis was validated by spectroscopic techniques like FTIR, 1H- NMR, 13C-NMR and chemical structure of title compounds 3 and 4 has been determined using SC-XRD. Ancillary to experimental analysis, DFT calculations with B3LYP/6-311 + G (d,p) level were performed for comparative analysis of FT-IR spectroscopic data, optimized geometry, frontier molecular orbitals (FMOs), natural bond orbital (NBO) analysis and nonlinear optical (NLO) properties. Overall, experimental findings were supported by corresponding DFT computed results. TDDFT calculations were executed at M06/6-311 + G (d,p) level of theory to calculate the vertical electronic transition states. NBO analysis disclosed that intramolecular charge transfer and hyper-conjugative interactions among bonds provide stability to the investigated compounds 3 and 4. The global reactivity parameters calculated from energy of FMOs indicates that 3 and 4 enclose larger softness and fewer hardness values. NLO results of 3 and 4 were observed better than standard molecule recommended the NLO activity of said compounds. We hope that this joint experimental and computational insight may provide new ways for the utilization of title molecules as NLO material for optoelectronic applications. Image 1 • Two novel ethyl 2-(2-(2-substitutedbenzylidene)hydrazinyl)thiazole-4-carboxylate crystals were synthesized. • XRD, 1H NMR, 13C NMR, FT-IR and UV–Vis were performed for the characterization. • Computational study was done at B3LYP/6-311 + G (d,p) level for comparative analysis. • Comparative study reveals a good agreement between experimental and DFT results. • FMOs, NBO analysis and nonlinear optical (NLO) properties were calculated. [ABSTRACT FROM AUTHOR]