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[Display omitted] • Six new anthracene based novel D–π–A organic dyes have been designed for DSSCs. • Substitution of –NO 2 and –CN (as donors) and –NH 2 and –N(CH 3) 2 (as acceptors) on 9,10-(bis-4-phenylazenyl)anthracene increases its light harvesting efficiency. • The dye bearing –N(CH 3) 2 (donor) and –NO 2 (acceptor) shows the greater bathochromic shift and broader absorption. • The greater charge transfer and highest λ max (994 nm) is also achieved for the same dye. The rational design of dyes for Dye-sensitized solar cells (DSSC) is challenging not only because the dye should absorb in the visible region but also have a favorable alignment with the semiconductor material. Dye sensitized solar cells (DSSCs) with donor-pi-acceptor (D-π-A) organic dyes have received significant interest by the scientific community since last few decades. In the present research work, six dyes (A1-A6) are designed based on 9,10-(bis-4-phenylazenyl)anthracene (R) skeleton by placing substituents on this scaffold. Density functional theory (DFT) and time dependent-DFT (TD-DFT) methods are used to theoretically investigate the optoelectronic properties of these dyes in order to study their potential for DSSCs application. It is also observed that the functionalization of reference compounds with different donor and acceptor groups increases electron injection and internal charge transfer (ICT) in the dye. The results of frontier molecular orbitals (FMO) indicate that the energy gap (E H-L) in A1-A6 is smaller than the reference compound. Among all the proposed dyes, A5 (the dye molecule with the largest number of donor moieties) showed the lowest band gap of 1.06 eV with a maximum absorption wavelength (λ max) value of 994 nm. Different parameters such as light harvesting efficiency (LHE), the free injection energy (ΔG inject), the dye regeneration energy (ΔG reg), open circuit voltage (V oc), reorganization energy (λ total), and excited state energy (τ) are also calculated. TDM analysis are also computed for all the proposed dyes from A1 to A5 and reference compound in order to understand the electronic excitation process. The theoretically calculated values of chemical hardness (η), and chemical potential (μ) suggest that changing the donor and acceptor groups on R compound can change the conductivity and ICT of dyes effectively. The dye A5 shows the lowest value for V oc i.e., 0.08 eV, which is sufficient for spontaneous transfer of electron from the LUMO of the dye to TiO 2 semiconductor. These results reveal that by modifying the donor and acceptor groups, the photovoltaic properties of the molecules can be enhanced. This theoretical work may provide a new path for experimentalists to synthesize these dyes for high performance DSSCs. [ABSTRACT FROM AUTHOR]

In this study, oxygenated triarylmethyl (oxTAM) is investigated by DFT calculations as a drug carrier framework for Nitrosourea (NU) and Fluorouracil (FU) drugs. Based on the adsorption analysis i.e. , energies and distances between interacting atoms, it is found that oxTAM exhibits excellent carrier abilities for the delivery of FU (−1.53 eV & 2.00 Å) and NU (−1.33 eV & 2.12 Å) drugs. NCI and QTAIM results indicate the presence of hydrogen bonding in drug-carrier complexes. The values of dipole moment and global chemical descriptors show the significant reactivity of oxTAM for NU and FU drugs. Based on electronic property analysis, FU@oxTAM has a higher adsorption trend for complexation with oxTAM as compared to NU@oxTAM. Moreover, FU can easily release from the carrier due to the decreasing adsorption stability after protonation under an acidic environment as well as a short recovery time observed for the oxTAM carrier surface. Keeping in view all the above parameters, we inferred that oxTAM can serve as a potential drug delivery system for anticancer drugs including, Nitrosourea and Fluorouracil drugs. [ABSTRACT FROM AUTHOR]

The desirability of the high nonlinear response of two-dimensional (2D) materials for electronics and optoelectronic devices drove us to investigate the nonlinear optical (NLO) behavior of alkali metal atom (AA) doped lithiated boron-containing hexahydroxy-triphenylene (LiBHHTP). In this context, the geometric, electronic, optical, and NLO properties are investigated. The doped AA atoms including Li, Na, and K preferably interact via the oxygen atoms of the LiBHHTP surface. The stability of the doped complexes is revealed by the interaction energies (E int), which are −22.90, −16.10, and −16.52 kcal/mol for Li@LiBHHTP, Na@LiBHHTP, and K@LiBHHTP complexes, respectively. The alterations in the electronic behavior of LiBHHTP are observed upon doping with alkali atoms via Frontier Molecular Orbital (FMO), Natural Bond Orbital (NBO), and the Density of State (DOS) analyses. The FMO analysis reveals that these complexes are electride in nature with absorption transparency in the UV–Vis range. Finally, the NLO behavior of designed complexes is evaluated through static and dynamic hyperpolarizabilities. Among reported complexes, K@LiBHHTP exhibits significantly large static hyperpolarizability (βₒ), 2.24 × 105 au. The dynamic NLO response of doped LiBHHTP complexes is also high, where the values are ranged in between 3.67 × 105 and 6.04 × 108 au at 1064 nm. This article not only highlights the effects of alkali atom doping on the NLO behavior of materials but also presents the first Lithiated boron-containing triphenylene as a next-generation optoelectronic material. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The drug carrier ability of B 3 O 3 toward Foscarnet is investigated via DFT. • The interaction is characterized by the geometric, energetic, electronic, and optical analyses. • Widely accepted ωB97XD/6-31+G(d,p) method of DFT is adopted for geometric analysis whereas for electronic properties B3LYP/6-31+G (d,p) method is used. • NCI and QTAIM analyses confirmed the nature of interactions. In this study, B 3 O 3 quantum dot is investigated via density functional theory (DFT) calculations as an antiviral drug carrier toward Foscarnet. Geometric analysis is carried out to find stable orientations of interaction between Foscarnet drug and the B 3 O 3 quantum dot. As a result, three stable orientations are proposed. The E int of the most stable orientation is –32.63 kcal/mol whereas the BSSE corrected energy is −26.98 kcal/mol. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses are employed to understand the nature and the type of interactions taking place between drug and the B 3 O 3 quantum dot. Their results indicated the presence of hydrogen bonding in the most stable complex (orientation A). The HOMO-LUMO analysis is performed to study the electronic properties of the interacting moieties. The lowest E gap is observed in case of orientation A. The value of dipole moments and chemical descriptors showed the significant activity of B 3 O 3 quantum dot toward Foscarnet drug molecule. The overall findings from this study suggest the B 3 O 3 quantum dot as a potential drug carrier system for antiviral drugs. [ABSTRACT FROM AUTHOR]

In this study, for the first time, static and dynamic NLO responses of pure and superhalogen doped aromatic heterocyclic monomers have been investigated by using density functional theory (DFT) calculations. The thermal, electronic, linear, and nonlinear optical properties are computed at the ωB97XD/6-31+G(d,p) method. The thermodynamic stabilities of reported complexes are estimated based on interaction energies, which are in the range of −28.06 to −83.20 kcal/mol. The lowest interaction energies are observed for AlF 4 @X (X = C 4 H 4 NH, C 4 H 4 O, C 4 H 4 S, and C 5 H 5 N) complexes, which correspond to their higher stabilities. The appreciable decrease in the HOMO-LUMO energy gap (E gap) is an indicative of the increase in reactivity after doping with superhalogens. The decrease in E gap is further demonstrated with the help of density of state (DOS) analysis. The significant nonlinear optical responses of the superhalogen doped aromatic heterocyclic monomers are due to the strong electron-withdrawing nature of the fluorine atom. Overall, the results indicate the high NLO response for the AlF 4 @X complexes due to the presence of four electron-withdrawing fluorine atoms in AlF 4. The NLO results are further analyzed through the two-level model. • Superhalogen doping of aromatic heterocyclic monomers is investigated for enhancement of NLO response. • HOMO-LUMO gap significantly decreases upon complexation. • AlF 4 @X exhibit significant thermodynamic stability upto −83.20 kcal/mol. • AlF 4 @X showed excellent third order nonlinear response. [ABSTRACT FROM AUTHOR]

Despite the numerous publications describing the photocatalytic and electronic properties of heptazine-based C 3 N 4 , the systematic study on the sensing behavior of pure heptazine-C 3 N 4 toward harmful chemical warfare agents (CWAs) is still lacking. Herein, we performed DFT calculations to investigate the adsorption behavior of C 3 N 4 toward various harmful and toxic CWAs including formaldehyde (OCH 2), thioformaldehyde (SCH 2), phosgene (OCCl 2), and thiophosgene (SCCl 2). ωB97XD functional of DFT along with 6–31G (d, p) basis set is used for all calculations for accurate estimation of noncovalent interactions. The CWAs are physiosorbed onto the C 3 N 4 having calculated interaction energy between −16.01 and −11.00 kcal/mol. Noncovalent interactions are further analyzed by symmetry-adapted perturbation theory (SAPT0), noncovalent interaction index (NCI), and quantum theory of atoms in molecules (QTAIM) analyses. The electronic behavior is characterized by the HOMO and LUMO energies, their energy gaps, and natural bond orbital (NBO) charge transfer. The charge transportation either donation or back donation is characterized by energy density difference (EDD) and charge decomposition analysis (CDA) analyses. The results demonstrate the trend of sensitivity of C 3 N 4 for toxic gases is OCH 2 @C 3 N 4 > SCH 2 @C 3 N 4 > OCCl 2 @C 3 N 4 > SCCl 2 @C 3 N 4. This theoretical work suggests that the C 3 N 4 can act as a good electrochemical sensor for a variety of toxic gaseous molecules. [Display omitted] • The sensing abilities of C 3 N 4 towards toxic molecules have been characterized by using ωB97XD/6-31G(d, p) level of DFT. • The sensing behavior of C 3 N 4 is studied through interaction geometries, energies, and electronic properties. • Among designed structures, OCH 2 @h-g-C 3 N 4 exhibits the strongest interaction due to electrostatic interactions. • C 3 N 4 exhibits significant sensitivity towards toxic molecules. [ABSTRACT FROM AUTHOR]

The aim of this study was the design of novel NLO materials based on superalkali doped NH 2 -GDY. Accurate analysis of the interaction stability was obtained at the ωB97XD/6–31+G(d, p) level of theory. Geometric, energetic, electronic and hyperpolarizability analyses collectively illustrate the remarkable static and dynamic NLO response of the reported complexes. [Display omitted] Keeping in mind the desirability of novel two-dimensional materials with an ultra-high nonlinear optical (NLO) response for the fabrication of optoelectronic devices, we have investigated nine complexes by doping superalkalis (M 2 X; M = Li, Na, K and X = F, Cl, Br) onto the novel aminated graphdiyne (NH 2 -GDY) quantum dots. The geometric, electronic and NLO responses (static and dynamic) of the M 2 X doped aminated graphdiyne (M 2 X@NH 2 -GDY) complexes have been systematically investigated using density functional theory (DFT) computations. All the superalkalis are preferably oriented on the triangular large porous site of NH 2 -GDY containing extensive delocalized π-conjugated electrons and interact via an intermolecular π-electron donor–acceptor (D-π-A) process. The lithium and potassium-containing superalkali doped complexes exhibit high structural stability due to their large interaction energies. The change in the electronic properties of the M 2 X doped NH 2 -GDY quantum dots is investigated by analyzing the NBO charge transfer, vertical ionization energies (VIEs), HOMO-LUMO energy gaps and density of states spectra. TD-DFT calculations show ultra-high transparency of these complexes in the ultraviolet region. The strong NLO characteristics of the designed complexes are demonstrated by their high static and dynamic hyperpolarizability values. Among all the nine complexes, the K 2 F@NH 2 -GDY, K 2 Cl@NH 2 -GDY and K 2 Br@NH 2 -GDY complexes possess exceptionally high β o values: 1.16 × 104, 1.06 × 104 and 1.02 × 104 au, respectively, owing to the large atomic radius and high atomic number of the potassium metal atoms. The frequency-dependent NLO responses, Electro-Optical Pockels Effects (EOPE) and Second Harmonic Generation (SHG) are analyzed to investigate the dynamic NLO response. It is revealed that the K 2 X@NH 2 -GDY complexes also exhibit exceptionally high dynamic NLO responses (107 or 108 au) at 1064 nm wavelength. Our present research not only highlights the significance of superalkali doping on aminated graphdiyne quantum dots but also indicates that the K 2 X@NH 2 -GDY complexes are potentially important for next-generation optoelectronic devices. [ABSTRACT FROM AUTHOR]

The sensing affinity of C 4 N is the most fascinating topic of research due to its excellent chemical and electronic properties. Moreover, owing to the highly active porous cavity, C 4 N can easily accommodate foreign molecules. Herein, we studied the adsorption properties of carbamate insecticides (CMs) namely, Dimetalin (DMT), Carbanolate (CBT), Isolan (ISO) and Propoxur (PRO) using density functional theory calculations. All the results are calculated at widely accepted ωB97XD functional along with 6-31G(d, p) basis set. The calculated counterpoise corrected interaction energy of the reported complexes ranges between −20.05 and −27.04 kcal/mol, however, the interaction distances are found to be higher than 2.00 Å. The values of interacting parameters depict that the carbamate molecules are physisorbed via noncovalent interactions that can easily be reversible. Moreover, the binding of selected insecticides notably changes the electronic structure of C 4 N. The electronic changes are characterized by the energies of HOMO & LUMO, their energy gaps and CHELPG charge transfer. The charge density difference between C 4 N surface and carbamate pesticides are characterized by EDD and CDA analysis. Moreover, the ab initio molecular dynamic study reveals that the complexes are stable even at 500 K. The photochemical sensing properties of C 4 N are estimated by time dependent UV–Vis calculations. The high sensitivity of C 4 N towards considered analytes enable it to act as a promising sensor for toxic pesticides. [Display omitted] • The sensing of C 4 N towards carbamate insecticides is investigated within the framework of DFT. • The results are characterized by the geometric, energetic, electronic, and optical analyses. • All the results are computed at ωB97XD/6-31G (d,p) level of DFT. • The trend of thermodynamic stability of complexes is as follow; DMT@C4N > CBT@C4N > ISO@C4N > PRO@C4N. [ABSTRACT FROM AUTHOR]

C 4 N is a novel porous two-dimensional material with fascinating electronic and chemical properties. Thereby, the sensing ability of C 4 N is the most aspect topic of research nowadays. In this study, potential application of C 4 N nanoflake as a chemical sensor for the toxic pesticides has been investigated using density functional theory calculations. The sensing ability of C 4 N for pesticides is evaluated through the interaction energy, noncovalent interaction index (NCI), quantum theory of atoms in molecule (QTAIM), molecular orbitals and CHELPG charge transfer analyses. The first principle calculations on ωB97XD/6-31G(d, p) level of DFT show that the C 4 N is selectively sensitive to Dichlorodiphenyltrichloroethane (DDT), Fenitrothion (FNT), Dimethoxy (DMDT), Ronnel (RN) and Fenthion (FT). The interaction of pesticides leads to the significant changes in the electronic structure of C 4 N. The observed sequence of interaction energy of our reported complexes is DDT@C 4 N > FNT@C 4 N > DMDT@C 4 N > RN@C 4 N > FT@C 4 N. The electronic structure changes can be demonstrated from two aspects: the strong interaction between pesticide molecule and C 4 N, the variation in HOMO-LUMO orbital energies and charge transfer from C 4 N to pesticide. The charges distribution between analytes and C 4 N nanoflake on interaction is analyzed by the electron density differences (EDD) and charge decomposition analysis (CDA). Our results reveal the potential application of C 4 N in electronic and sensor devices especially for the detection of toxic chemicals. [Display omitted] • The sensing of C 4 N nanoflake toward pesticides is investigated theoretically. • The results are based on the geometric, energetic, and electronic analyses. • ωB97XD and M052X-D3/6-31G (d,p) levels of DFT are implemented to measure the sensing affinity of C 4 N. • The thermodynamic stability is in the order of DDT@C 4 N > FNT@C 4 N > DMDT@C 4 N > RN@C 4 N > FT@C 4 N. [ABSTRACT FROM AUTHOR]