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In this study, for the first time, boron oxide nanoflake is analyzed as drug carrier for favipiravir using computational studies. The thermodynamic stability of the boron oxide and favipiravir justifies the strong interaction between both species. Four orientations are investigated for the interaction between the favipiravir and the B3O3 nanoflake. The Eint of the most stable orientation is −26.98 kcal/mol, whereas the counterpoise-corrected energy is −22.59 kcal/mol. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses are performed to obtain insights about the behavior and the types of interactions that occur between B3O3 nanoflake and favipiravir. The results indicate the presence of hydrogen bonding between the hydrogen in the favipiravir and the oxygen in the B3O3 nanoflake in the most stable complex (FAV@B3O3-C1). The electronic properties are investigated through frontier molecular orbital analysis, dipole moments and chemical reactivity descriptors. These parameters showed the significant activity of B3O3 for favipiravir. NBO charge analysis transfer illustrated the charge transfer between the two species, and UV-VIS analysis confirmed the electronic excitation. Our work suggested a suitable drug carrier system for the antiviral drug favipiravir, which can be considered by the experimentalist for better drug delivery systems. [ABSTRACT FROM AUTHOR]

Herein, a series of D‐π‐A conjugated molecules based on donor N‐methyl‐4,5‐diazacarbazole with a variety of acceptor end caps are quantum chemically proposed with aim of rational design of novel organic materials applicable in organic solar cells (OSCs) by using ab initio density functional theory (DFT) calculations. Herein, the optoelectronic performance of tailored molecules was explored by substituting the bay annulated indigo dye acceptor unit with a variety of molecules including 4‐(5‐methyl‐thiophene‐2‐yl)benzothiadiazole; 1, 2‐(3‐methyl‐5‐methylene‐4‐oxothiazolidin‐2‐ylidene)‐malononitrile; 2, 3‐methyl‐5‐methylene‐2‐thioxothiazolodin‐4‐one; 3, 2‐methylenemalononitrile; 4, 2‐cynaoacryli‐caidmethylester; 5, those are linked through the thiophene bridge. The DFT results encompassed the significant variations of electronic behavior of newly designed molecules (M1‐M5) with respect to the reference molecule, especially in the case of 1, 2, and 3 substitution. The designed molecules exhibit excellent electron transition due to the increasing λmax toward the higher region. The outcomes of this study proposed the designed molecules as a possible choice in designing efficient optoelectronic materials for OSCs. From the future point of view, this finding suggests that the pre‐synthesis of such hypothetical molecules using quantum mechanics is an effective strategy for designing ideal candidates for solar cell applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The chiral recognition ability of CBPQT4+ is systematically studied using DFT simulations. • Chirodiastalic energy (E chir) indicates the L -enantiomer complexes are more stable than D -complexes. • The quantitative analyses of noncovalent interaction indicate the structures are stabilized by the dispersion forces. • The electronic properties analyses illustrate the high chiral response of CBPQT4+ towards small molecular amino acids. • Overall findings reveal that the CBPQT4+ macrocycle has an excellent ability to differentiate between L - and D -enantiomers. Two enantiomeric forms of amino acids in a chiral medium behave quite differently because of the different orientation of their functional groups in space. Thus, the phenomenon of chiral recognition is crucial with the focus on applications in molecular sensing and enantioselective separations. The present research work is focused on the illustration of the potential chiral recognition of a porous CBPQT4+ macrocycle for sulfur-containing amino acids, which is elucidated by the conformational energies landscape with quantitative non-covalent analysis and their electronic behaviour. Herein, we report the chiral recognition of sulfur-containing amino acids e.g., cysteine (CY), homocysteine (HCY), and methionine (MT), by tetra-protonated (4+) CBPQT macrocycle via density functional theory (DFT) calculations. Geometry optimization, thermodynamic stability, noncovalent interaction analysis, symmetry-adapted perturbation (SAPT), and electronic properties analyses are employed to characterize the chiral response of the complexes formed by CBPQT4+ with D - and L -isomers of selected amino acids. The interactive conformations of complexes indicate physisorption of amino acids through the central cavity of the macrocycle. The maximum chiral discrimination is observed in the case of D - and L -cysteine isomers, which is 3.56 kcal/mol. It is revealed that the complex; D -CY@CBPQT4+ is energetically more stable than the L -CY analogue, whereas, L -HCY and L -MT show higher stability as compared to D -type counterparts, probably due to the interaction of the thiol groups with π-electrons of macrocycle in respective stable complexes. Non-covalent interaction (NCI) analyses including, reduced density gradient-based NCI index and SAPT reveal that the methionine-based complexes show the highest attractive components e.g., electrostatic, dispersion, and induction with the lowest repulsive exchange contribution, which is followed by homocysteine and cysteine. Overall, results show that the CBPQT4+ macrocycle has an excellent ability to differentiate between L - and D -amino acids, the difference is more pronounced when the structure of amino acid is small and rigid. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the first time, DFT study of superalkalis doped C 16 Te 8 is performed. • Designed complexes have promising thermodynamic stabilities. • Static first hyperpolarizability up to 2.60 × 105 au is obtained for doped complexes. • Large nonlinear refractive index value up to 1.55 × 10−12 au is observed for doped complexes. There is a growing demand for thermodynamically stable and highly polarizable materials with excess electrons in the fields of optics. In this study, a new class of theoretically designed materials (A x Y@C 16 Te 8 (A = K, Na, Li, and x = 2, 3 4)) are explored for optoelectronic and nonlinear (NLO) applications via DFT calculations. Various superalaklis (A x Y (Y = O, N, F and x = 2, 3, 4)) are doped on C 16 Te 8 nano-surface. The outcomes of DFT revealed high thermodynamic stability of these complexes. Natural bond orbital (NBO) charge analysis illustrated that charge transfer occurred from superalkali toward Te-containing [8]circulene (C 16 Te 8). HOMO − LUMO energy gap is reduced after doping. Moreover, (A x Y@C 16 Te 8 (A = K, Na, Li, x= 2, 3 4, and Y = O, N, F) complexes exhibit remarkably large nonlinear optical (NLO) response. The static first hyperpolarizability (β o) of these complexes ranges between 3.28 × 103 – 2.60 × 105 au. The NLO response of the designed complexes is further explored by computing second hyperpolarizability (γ tot ), frequency-dependent hyperpolarizability, and nonlinear refractive index. [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]

[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]

[Display omitted] • Sensing of gaseous molecules on aza-macrocyle is studied using DFT approach. • The adsorption behaviour is analyzed via geometric, energetic, and electronic properties. • The effect of applied electric field is studied for reported complexes. • The adsorption trend of is as follow: SO 3 @HA ≫ SO 2 @HA > H 2 S@HA ≫ NO 2 @HA > N 2 O@HA. The toxic gas sensing applications find immense attention in environmental monitoring. In this research, the adsorption of nitrogen and sulfur-containing gaseous molecules i.e., N 2 O, NO 2 , H 2 S, SO 2 and SO 3 on organic aza-macrocyclic hexaazabipyH 2 (HA) is analyzed through DFT simulations. The interactions of toxin analytes with HA are expressed through the interaction stabilities of optimized geometries, and electronic parameters including highest occupied and lowest unoccupied molecular orbitals energies and NBO charged transfer analysis. Our results indicate that the gaseous molecules are physisorbed onto the HA with the interaction energies of −4.80, −4.86, −7.09, −7.42 and −11.64 kcal/mol for NO 2 , N 2 O, H 2 S, SO 2 and SO 3 , respectively. The trend of interaction stability of complexes is observed as, SO 3 @HA > SO 2 @HA > H 2 S@HA > N 2 O@HA > NO 2 @HA. The adsorption of the gaseous molecule on the electronic structure of HA is significant, especially for sulfur-containing analytes. The effects of the applied electric field from the range of −0.15 to +0.15 V/Å in the direction of adsorbed molecules (Y-axis) on the interaction energies and dipole moment of complexes have been measured. It can be concluded that the HA macrocycle shows greater sensitivity towards the toxic gas molecules and therefore, can be applied for their sensing. [ABSTRACT FROM AUTHOR]

Motivated by the excellent geometric and electronic properties of recently reported triphenylene (TP), for the first time, we studied the nonlinear optical responses of superalkalis (Li 3 O and Na 3 O) doped triphenylene and amino (HATP), hydroxy (HHTP) and thiol (HTTP) functionalized quantum dots by using density functional theory. The geometric stabilities of eight reported complexes are measured through the interaction energies at ωB97XD/6-31+G(d,p) level of theory. Our results reveal that Li 3 O@HATP and Na 3 O@HATP complexes are highly stable with the interaction energies of −60.36 and −57.26 kcal/mol, respectively. The HOMO-LUMO energy gaps of TP, HATP, HHTP and HTTP are significantly varied upon complexation with M 3 O which is evident by the strong charge transfer from excess electron donor superalkalis (M 3 O) to the surfaces. However, the π back donation is more pronounced in M 3 O@HATP complexes, revealed by the negative value of CHELPG charge transfer on M 3 O. Due to the donation and back donation of charges between M 3 O and HATP, the significantly high first static hyperpolarizability ( β o ) and its projection to dipole moment ( β vec ) are computed for M 3 O@HATP complexes. The β o of Li 3 O@HATO and Na 3 O@HATP complexes are 3 × 104 au. The β o of Na 3 O@HHTP complex is surprisingly high (1 × 105 au) which is justified by the two-level model. Moreover, the NLO responses of co-doped Li 3 O/Na 3 O and mixed functional groups TP-quantum dots are also computed. Among them, the maximum β o (5 × 104) is observed for the Na 3 O@AHTP complex. Finally, the TD-DFT calculations reveal that the reported complexes show excellent transparency in the ultraviolet region especially M 3 O@HATP and Na 3 O@HHTP complexes. [Display omitted] • The NLO response of superalkalis (M 3 O) doped TP, HATP, HHTP and HTTP are computed. • The NLO responses of these novel complexes are investigated in the framework of density functional theory (DFT) calculations. • The results are rationalized by analyzing the geometric, energetic, electronic, linear and nonlinear optical properties. • Theoretical results reveal that Na 3 O@HATP, Li 3 O@HATP and Na 3 O@HHTP complexes exhibit superior optical behavior. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study theoretically presents the sensing affinities of cyclic tetrapyrrole (CTPy) towards toxic gaseous molecules. • The sensitivity of CTPy is measured against the toxic chemicals namely NH 3 , NF 3 , NCl 3 and NBr 3. • ωB97XD/6-31+G(d, p) level of DFT has implemented to measure the sensitivity of CTPy. • DFT results proved that CTPy is highly sensitive towards the considered analytes. Toxic gas sensors with ultrahigh sensitivity are highly desirable and those can be achieved with the help of infinite π-conjugation of cyclic conducting polymers. In this DFT study, we demonstrate the adsorption performance of tetracyclic oligopyrrole (CTPy) towards NH 3 and nitrogen halides including NF 3 , NCl 3 and NBr 3. The CTPy possesses infinite conjugation and highly active cavity which provides an excellent platform for the adsorption of upcoming gas molecules. Thermodynamically, the observed interaction energies of NH 3 , NF 3 , NCl 3 and NBr 3 analytes with CTPy at ωB97XD/6-31+G(d,p) level of theory are −13.14, −3.00, −6.00 and −7.50 kcal/mol, respectively. In addition, the molecular dynamic simulations are performed at GFN2-xTB method to confirm the stability of CTPy and respective complexes. The SAPT0 and NCI analyses reveal that dispersion forces play a significant role to stablize these complexes. Moreover, the electrostatic component also contributes in stabilizing the NH 3 @CTPy, NCl 3 @CTPy and NBr 3 @CTPy complexes. The variation in the electronic properties including HOMO-LUMO gaps of complexes along with the significant NBO charge transfer indicate the increasing conductivity of CTPy upon complexation with reported analytes. The prominent charge transfer on interaction might be due to the increasing π to π* transition, thus the λ max is shifted to longer wavelength in UV–vis spectra. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT studies are executed for hydrogen storage on Germanium (Ge 5 −2 & Ge 9 −2) and Silicon (Si92−) Zintl clusters. • The superior adsorption behavior of Zintl ions is illustrated by comparing with neutral analogues. • The adsorption behavior is investigated by using M052X/6-31+G(d,p) method. • The storage capability is explained with the help of geometric and electronic properties. Hydrogen storage is a subject of extensive research because hydrogen is a clean and eco-friendly for future applications. New strategies are being developed simultaneously for the easy and effective storage of hydrogen gas. Herein, we report the hydrogen adsorption on the Germanium and Silicon Zintl clusters within the framework of density functional theory (DFT). The excellent adsorption of hydrogen on Ge 5 2−, Ge 9 2−, Si 9 2− based Zintl clusters is achieved in terms of adsorption energies, electronic properties such as, HOMO-LUMO gaps, natural bond orbital (NBO) charge transfer, variation in dipole moment and density of state analysis (DOS). The superior adsorption affinities of these Zintl clusters are demonstrated in comparison with the adsorption capability of Ge and Si neutral clusters. In comparison, the adsorption energies of H 2 @Zintl phase complexes are higher than those of corresponding H 2 @neutral clusters. For example, the adsorption energy of b- exo -H 2 @Si 9 2− complexes is −11.13 kJ mol−1 which is far higher than −3.47 kJ mol−1 for the neutral analogue (b- exo -H 2 @Si 9 0). The effect of hydrogen adsorption on the E H-L gaps in Zintl clusters is also more pronounced, and the higher charge transfer is observed as well. Overall, results suggest the higher adsorption strength of Zintl cluster for H 2 as compared to neutral clusters. [ABSTRACT FROM AUTHOR]

The sensing properties of 2D carbon materials are well explored for various gaseous analytes, however, the detection of toxic chemicals e.g. , phosgene (Ph), thiophosgene (ThP) and phosogenoxime (PhO) are rarely studied. To the best of our literature survey, only a single study is found for the adsorption of phosgene on 2D carbon nanoflake (graphyne). This motivated us to explore the sensitivity of graphdiyne (GDY) nanoflake for the detection of phosgene and couple of its derivatives. Therefore, we have performed a density functional analysis to simulate the comparative interaction between phosgene, thiophosgene and phosogenoxime with graphdiyne nanoflake. The interaction behaviours are estimated by interaction energies, (symmetry adopted perturbation) SAPT0 analysis, (noncovalent interaction index) NCI analysis, molecular orbital analysis, natural bond orbital (NBO) charge transfer and UV–Vis absorption analysis. The obtained results demonstrate the trend in sensitivity of graphdiyne for analytes is PhO@GDY > ThP@GDY > Ph@GDY. The sensible justification for the particular observation is provided by the energy gaps between HOMO and LUMO orbitals in term of %sensitivity. The %sensitivity is in complete accord with the aforementioned trend. In addition, results suggest that graphdiyne based sensor for detecting phosgene and derivatives are better in sensitivity in comparison with already reported graphyne sensor. Image 1 • Adsorption of phosgene, thiophosgen and phosogenoxime molecules on graphdiyne nanoflake is studied. • ωB97XD/6-31+G (d,p) level of DFT has implied to elucidate the sensing applications. • Graphdiyne is highly sensitive toward phosgene and related derivatives. [ABSTRACT FROM AUTHOR]

Although citric acid (CA) has antioxidant, antibacterial, and acidulating properties, chronic ingestion of CA can cause urolithiasis, hypocalcemia, and duodenal cancer, emphasizing the need for early detection. There are very few documented electrochemical-based sensing methods for CA detection due to the challenging behavior of electrode fouling caused by reactive oxidation products. In this study, a novel, non-enzymatic, and economical electrochemical sensor based on cobalt oxide nanoparticles (CoO x NPs) is successfully reported for detection CA. The CoO x NPs were synthesized through a simple thermal decomposition method and characterized by SEM, FT-IR, EDX, and XRD techniques. The proposed sensing platform was optimized by various parameters, including pH (7.0), time (15 min), and concentration of nanoparticles (100 mM) etc. In a linear range of 0.05–2500 μM, a low detection limit (LOD) of 0.13 μM was achieved. Theoretical calculations (ΔRT), confirmed hydrogen bonding and electrostatic interactions between CoO x NPs and CA. The detection method exhibited high selectivity in real media like food and biological samples, with good recovery values when compared favorably to the HPLC method. To facilitate effective on-site investigation, such a sensing platform can be assembled into a portable device. [Display omitted] • Novel Cobalt oxide electrochemical sensing platform for citric acid detection. • Insight mechanistic with Density functional theory studies has been investigated. • Achieving a low detection limit of 0.13 μM within a linear range of 0.05–2500 μM. • Effective integration of real samples for use in clinical and food industries. • Great potential of fabricating a device for on-site measurements. [ABSTRACT FROM AUTHOR]