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The present investigation highlights the 2-dimentional design of several interesting super alkali doped borophene derivatives for efficient nonlinear optical (NLO). Borophene (B36) and super alkali units (Li3O) whose combining effects and resulting NLO responses have been evaluated by orienting super-alkali clusters at various sites such as a hub, rim, and bridged around the B36 molecule. The charge analysis is characterized by frontier and natural bond orbital analysis, narrowed HOMO-LUMO band gap, better intramolecular charge transfers. Molecular electrostatic potential surfaces demonstrate enhanced optoelectronic features of these complexes that are viable owing to Li3O adsorption. Singly doped and doubly doped complexes have been considered and their NLO properties have been calculated. Band gap energy reduces about three times when doped with two Li3O. A considerably high figure of merit, first hyperpolarizability (bo) values up to five digits 10611 a. u. for complex A proved that these systems can be utilized as promising candidates in various NLO applications.

The present investigation highlights the two-dimensional design of several interesting superalkali-doped borophene derivatives for efficient nonlinear optics (NLO). The combination effects and resulting NLO responses of borophene (B

Though the gas sensing applications of graphdiyne have widely reported; however, the biosensing utility of graphdiyne needs to be explored. This study deals with the sensitivity of graphdiyne nanoflake (GDY) towards the uric acid (UA) within the density functional framework. The uric acid is allowed to interact with graphdiyne nanoflake from all the possible orientations. Based on these interacting geometries, the complexes are differentiated with naming, i.e., UA1@GDY, UA2@GDY, UA3@GDY, and UA4@GDY (Fig. 1). The essence of interface interactions of UA on GDY is derived by computing geometric, energetic, electronic, and optical properties. The adsorbing affinity of complexes is evaluated at ωB97XD/6–31 + G(d, p) level of theory. The stabilities of the complexes are quantified through the interaction energies (Eint) with reasonable accuracy. The calculated Eint of the UA1@GDY, UA2@GDY, UA3@GDY, and UA4@GDY complexes are − 31.13, − 25.87, − 20.59, and − 16.54 kcal/mol, respectively. In comparison with geometries, it is revealed that the higher stability of complexes is facilitated by π-π stacking. Other energetic analyses including symmetry adopted perturbation theory (SAPT), noncovalent interaction index (NCI), and quantum theory of atoms in molecule (QTAIM) provide the evidence of dominating dispersion energy in stabilizing the resultant complexes. The HOMO–LUMO energies, NBO charge transfer, and UV–vis analysis justify the higher electronic transition in UA1@GDY, plays a role of higher sensitivity of GDY towards the π-stacked geometries over all other possible interaction orientations. The present findings bestow the higher sensitivity of GDY towards uric acid via π-stacking interactions.

The geometric, thermodynamic and electronic properties of Pd–graphene nanocomposites are comprehensively studied through quantum mechanical methods. Geometries of these clusters are optimized with the well-calibrated Minnesota functional M06-2X. The adsorption energies calculated at the M06-2X/LANL2DZ level show better agreement with those calculated from MP2/ANO-RCC-VDZP. Two different representative models for graphene, coronene and hexabenzocoronene, are used. The adsorption energies analysis reveals that the interaction energies increase with the size of the adsorbed cluster. However, for Pdn/hexabenzocoronene, the interaction energies show a sudden drop at Pd8/hexabenzocoronene. The difference in behavior between the interaction energies of Pdn/hexabenzocoronene and Pdn/coronene is attributed to the edge effect present in coronene. The electronic properties, including highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), Fermi level, molecular electrostatic potential (MEP), dipole moment, vertical ionization potential (VIP), vertical electron affinity (VEA), chemical hardness (η), softness (S) and chemical potential (μ) are studied. The VIP and VEA reveal that Pdn/coronene clusters are stable in nature with the least reactivity. The HOMO–LUMO energy gaps are reduced with the increase in cluster size. The electronic properties show irregular trends, where the most favorable electronic properties are obtained for Pd7/coronene and Pd10/coronene.

Electrides are excess electron compounds with excellent nonlinear optical properties. Herein we report the geometric, electronic, and nonlinear optical properties of C6Li6–M3O electrides. These electrides are designed by doping superalkalis (Li3O, Na3O, and K3O) on hexalithiobenzene (C6Li6). Density functional theory results reveal that charge transfer occurs from M3O to hexalithiobenzene (C6Li6). Ab initio molecular dynamics (AIMD) simulations at room temperature reveal that these complexes are quite stable thermodynamically. These electrides possess lower HOMO–LUMO energy gaps and crucial excitation energies than pristine C6Li6. The NLO response of the designed electrides is studied through first hyperpolarizability (βtot), second hyperpolarizability (γtot), frequency-dependent second harmonic generation (SHG), the electro-optic Pockels effect (EOPE), electric field-induced second harmonic generation (ESHG), the electro-optic Kerr effect (EOKO), hyper-Rayleigh scattering coefficient (βHRS) and nonlinear refractive index (n2). A remarkably high frequency induced dc-Kerr effect (up to 3.0 × 1016 a.u.) and ESHG (up to 2.2 × 1015 a.u.) are computed for the designed electrides. Moreover, these electrides also exhibit an enormously high quadratic nonlinear refractive index (up to 2.6 × 10−6 a.u.). This work provides new insights for designing stable organometallic electrides (C6Li6–M3O) with enhanced NLO response.

The permeation and selectivity of alkali metal atoms and ions through normal and defected hexagonal boron nitride was studied in the presence and absence of water and an electric field. The defects include one (VB & VN), two (VBN) and three atom (VN2B) vacancies. The morphology and size of the pore (defect) in the h-BN sheet significantly affect the energy barriers. These results indicate that an h-BN sheet with appropriate pore size possesses good Li/Li+ selectivity. The permeation of lithium atoms through VN2B-h-BN is almost a barrierless process (1.75 kcal mol−1). Moreover, the VBN h-BN nanosheet selectively allows the passage of Li atoms at room temperature with the highest selectivity ratio of 1.58 × 1013. The presence of water molecules increases the barrier of alkali metal atom permeation. The effect of water molecules is more pronounced for alkali metal atom permeation through a defected h-BN nanosheet as compared to alkali metal ions. An applied electric field perpendicular to the h-BN sheet further decreases the permeation barriers. For example, the energy barrier is reduced to 31 kcal mol−1 (from 34 kcal mol−1) in the presence of an electric field for the permeation of lithium through H2O–VB h-BN–H2O. These studies can be extended to investigate the separation capability of porous hexagonal boron nitride nanosheets for other metal atoms and ions.

Explosives are quite toxic and destructive; therefore, it is necessary to not only detect them but also remove them. The adsorption behavior of NX3 analytes (NCl3, NBr3 and NI3) over the microporous C2N surface was evaluated by DFT calculations. The nature of interactions between NX3 and C2N was characterized by adsorption energy, NCI, QTAIM, SAPT0, NBO, EDD and FMO analysis. The interaction energies of NX3 with C2N are in the range of −10.85 to −16.31 kcal mol−1 and follow the order of NCl3@C2N > NBr3@C2N > NI3@C2N, respectively. The 3D isosurfaces and 2D-RGD graph of NCI analysis qualitatively confirmed the existence of halogen bonding interactions among the studied systems. Halogen bonding was quantified by SAPT0 component energy analysis. The SAPT0 results revealed that ΔEdisp (56.75%) is the dominant contributor towards interaction energy, whereas contributions from ΔEelst and ΔEind are 29.41% and 14.34%, respectively. The QTAIM analysis also confirmed the presence of halogen bonding between atoms of NX3 and C2N surface. EDD analysis also validated NCI, QTAIM and NBO analysis. FMO analysis revealed that the adsorption of NI3 on the C2N surface caused the highest change in the EHOMO–LUMO gap (from 5.71 to 4.15 eV), and resulted in high sensitivity and selectivity of the C2N surface towards NI3, as compared to other analytes. It is worth mentioning that in all complexes, a significant difference in the EHOMO–LUMO gap was seen when electronic transitions occurred from the analyte to the C2N surface.

Nitro-explosives are a severe threat to the environment; therefore, detection and removal of nitro-explosives is the need of time. Herein, we illustrate the application of a newly discovered C2N surface for electrochemical detection and removal of nitro-explosives: namely, picric acid (PA), ethyleneglycoldinitrate (EGDN), and dimethyldinitrobutane (DMNB). Among the studied analytes, the highest adsorption energy of −25.12 kcal mol−1 (BSSE = −18.48 kcal mol−1) was observed for the PA@C2N complex. The nature of interactions was further quantified by SAPT0, NCI and QTAIM analyses, while the electronic properties were studied through EDD, NBO and FMO analyses. The SAPT0 analysis reveal that the dispersion factor remained dominant (60–64%) for stabilization of analyte@C2N complexes. The highest charge transfer was observed for PA@C2N (0.01e−), whereas the least amount of charge transfer was calculated for DMNB@C2N (−0.004e−). A more pronounced change in the EH–L gap was observed for PA@C2N (3.07 eV) compared to the DMNB@C2N (3.66 eV) and EGDN@C2N complexes (3.68 eV). It was noticed that a potential decrease in the EH–L gaps can be observed when the electronic transition occurs from the analyte to the C2N surface. The recovery time of PA is 35 s (298 K), which shows that the sensor can be easily recovered under ambient conditions. The results of various parameters reveal that C2N is more selective towards PA than toward the other studied analytes.

Excess electron generation through doping with alkali and superalkali metals is well known to enhance NLO responses. On the contrary, superhalogen doping is an unexplored dimension. Herein, we report the first ever examples where superhalogen doping alone is introduced as a new and effective approach to impart large NLO responses. Density functional theory (DFT) calculations illustrate that superhalogen (BeF3 and BeCl3)-doped cyclic oligofurans (nCF) possess exceptionally high NLO responses (first hyperpolarizability (β0), hyper-Rayleigh scattering coefficient (βHRS), electro-optical Pockels effect (EOPE), second harmonic generation (SHG), and nonlinear refractive index (n2)), which are not trivial for organic compounds. Upon doping with superhalogens, the first hyperpolarizability (β0) of nCF increases to 3 × 105 a.u. in the BeF3@6CF complex, whereas the β0 values of the BeF3@5CF, BeCl3@5CF and BeCl3@6CF complexes are 6 × 104, 3 × 104 and 4 × 104 a.u., respectively. An enormously large third order nonlinear optical response coefficient with an electric field-induced second harmonic generation (ESHG) value of 2.1 × 109 a.u. is observed for the BeCl3@6CF complex. The remarkable NLO responses of the superhalogen-doped cyclic oligofuran complexes are due to the electron withdrawing nature of the halogen atoms, which are responsible for withdrawing electrons from the oxygen atoms of nCF to create poles. The significant hyperpolarizability (β0) of the BeF3@6CF complex is due to the most electronegative nature of fluorine. Furthermore, these results are rationalized through a two-level model. Bvec values are calculated for these complexes because they give more meaningful numbers from an experimental point of view. The stability of the complexes is judged through interaction energies, whereas electronic properties are calculated by chemical reactivity descriptors, the HOMO–LUMO gaps (Eg) and NBO charge transfer analysis. TD-DFT calculations reveal that the maximum absorbance for the BeF3@6CF complex is shifted to the longest wavelength.

Cyclic oligofurans containing five and six furan rings (5CF & 6CF) doped with superalkalis are presented here as a new type of NLO material. The OLi3@nCF, ONa3@nCF and OK3@nCF (n = 5 & 6) complexes are optimized at the M05-2X/6-31+G(d,p) level of theory. In these complexes, the superalkalis maintain their identity, and interact through the cavity of the cyclic oligofurans (nCF). Nonlinear optical properties are obtained through first hyperpolarizability (βo) of the complexes. The NLO response is rationalized on the basis of dipole moment (μo), energies of crucial excitation states (Eex) and vertical ionization energies (VIE). The highest hyperpolarizabilities (βo = 5 × 107 a.u. and βvec = 3 × 107 a.u.) are observed for OK3@nCF complexes along with the lowest EH–L, prominent NBO charge transfer, the highest dipole moment, and pronounced polarizability. The remarkable NLO response is attributed to the generation of excess electrons by superalkali doping. UV-Vis spectra are calculated to realize the transparency of these complexes in the UV-Vis region. The results suggest that higher NLO response is obtained when superalkalis are doped in higher oligofurans.

Graphene/polythiophene composites are widely used in a variety of optoelectronic devices and applications, e.g., as electrode materials in capacitors and solar cells, but the detailed molecular-lev...

Photoswitchable catalysis involves changes in properties of a catalyst based on difference in electronic and steric factors. These changes can selectively turn “ON” and “OFF” the catalytic activity by an external stimulus, light. Herein, we report dithienylethene based photoswitchable frustrated Lewis pairs for facile hydrogen recombination. The diarylethene moiety is not serving as template to alter the catalytic activity rather it is the core part of the catalyst. The rational design principle involves study of proton and hydride affinities of Lewis acid and base functionalities installed on the diarylethene photoswitch pair. Proton and hydride affinities differ significantly between open and closed isomers that help in designing an active molecule for hydrogen recombination. The proton and hydride affinities are then utilized to formulate best relative positions of Lewis acid and base on a single molecule in order to liberate one H2 molecule per photochrome. Energy barriers for hydrogen recombination are calculated for open and closed isomers. The closed isomer releases the hydrogen with a low activation barrier of 1.9 kcal mol−1 whereas the open isomer requires relatively high barrier of 4.7 kcal mol−1. The pronounced differences in energy barrier illustrate the potential of photoswitchable hydrogen recombination with diarylethene photochrome. The chemically stored hydrogen in frustrated Lewis pairs can be liberated in a controlled fashion through external stimulus for catalytic hydrogenation reactions. The present study will provide new dimensions to the scientific community for exploration of other systems with even better selectivities.

Blends of acrylonitrile-butadiene rubber (NBR) with polyvinylchloride (PVC) form thermoplastic elastomers that are miscible in all compositions. NBR-PVC elastomers are used in many industri...

Based on DFT calculations, we designed a new series of superalkali doped graphdiyne (GDY) complexes, M2X@GDY (M = Li, Na, K and X = F, Cl, Br) having electron donor and acceptor (D-π-A) framework. Our results of interaction energies reveal that these superalkalis are quite stable and chemisorbed over the 18 membered site of GDY. DFT results also reveal that the doping of superalkalis on GDY leads to narrowing of the HOMO-LUMO gaps, which enhance their conductance properties. Furthermore, the polarizability and first hyperpolarizability of GDY are enhanced dramatically up to 7.7 × 104 au. The enhanced first hyperpolarizabilities are further explained by two level model expression from TD-DFT calculations. The TD-DFT results show that all these designed superalkali doped graphdiyne complexes have ultraviolet light transparency. To rationalize the hyperpolarizability trend in superalkali doped GDY complexes, βvec calculations are also performed. This study may provide better understanding for the direct synthesis of new GDY based NLO materials in industries.

Herein, we report the synthesis, characterization and biological evaluations of two novel organotin(IV) carboxylates (1 and 2). The structures of both complexes are confirmed by single crystal X-rays diffraction analysis. Density functional theory (DFT) studies are also executed to compare experimental (X-ray as well as spectroscopic) results with theoretical ones. Excellent correlation is observed between theoretical and experimental results. Furthermore, organotin(IV) carboxylates are evaluated against different bacterial stains (E. coli, S. aureus, K. pneumoniae and B. subtilis) and fungal stains (F. solani, A. fumigatus and A. niger). The complex 1 shows good antibacterial activity against B. subtilis (17 ± 0.32 mm), whereas complex 2 shows good antibacterial activity against E. coli (18 ± 0.41 mm) and B. subtilis (18 ± 0.41 mm). The complex 1 shows significant activity against A. fumigatus (28 ± 0.45 mm) and 2 shows good activity against A. fumigatus (16 ± 0.37 mm). To determine the interaction of organotin(IV) carboxylates with DNA, the interaction studies with salmon sperm DNA (SS-DNA) are also carried out through UV–vis absorption spectroscopy. The Gibbs free energies (ΔG) (−28.02 kJ/mol for complex 1 and -28.43 kJ/mol for complex 2) and high values of binding constants (K) (8.15 × 104 M−1 for complex 1 and 9.62 × 104 M−1 for complex 2) indicate that strong interactions are developed between organotin(IV) carboxylates and SS-DNA.

Continuous strides are being made to explore non-fullerene acceptors for organic solar cells. Here, optoelectronic properties of four new acceptor-donor-acceptor (A-D-A) type non-fullerene acceptor molecules are evaluated for their potential use in organic solar cells. The designed molecules contain indacenodithiophene (IDT) donor core connected with various acceptor groups through benzothiadiazole (BT) bridge unit. The designed molecules differ from each other in end-capped acceptor groups. The end-capped acceptors are 2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (M1), 2,5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (M2), 2-methylene-2-H-indene-1,3-dione (M3), and 2,5-methylene-6-oxo-5,6-dihydrocyclopenta-c-thiphen-4-ylidene-malononitrile (M4). The optoelectronic properties are evaluated in comparison with the recently reported R which is structurally similar to the designed molecules. The reference compound R contains indacenodithiophene (IDT) donor core unit with 3-ethyl-d-ethylidene-2-thioxothiazolidin-4-one end capped acceptor group. The A-D-A acceptor molecules evaluated here exhibit proper frontier molecular orbital diagram to facilitate the charge mobility. M2, containing 2-(5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile end-capped acceptor group, exhibits maximum absorption at 805 nm which is attributed to extended conjugation with the BT unit. Results of transition density matrix (TDM) show clear effect of end caped acceptor group on electro-hole exciton. Small coupling of electron and hole in M4 illustrates easy dissociation of exciton as compared with other molecules. Among all, M4 shows the highest hole transfer rate as revealed from low hole reorganization energy (λh). The open circuit voltage (Voc) of reference R is 1.96 V with donor polymer PTB7-Th while the designed molecule M3 exhibits the Voc of 2.02 V. Hence, the designed fullerene free acceptor molecules are suitable for transparent organic solar cells.

Recently, significant progress is observed in the design and synthesis of nonlinear optical materials due to their optoelectronic and biomedical applications. In this report, a series of inorganic electrides (Li2F@Al12P12, Li3O@Al12P12 and Li4N@Al12P12) are designed by doping of Al12P12 nanocluster with superalkalis (Li2F, Li3O and Li4N) and studied through density functional theory (DFT) for their geometrical, electronic and nonlinear optical properties. Computational results indicated that these superalkalis doped complexes possess high stability and low HOMO-LUMO gaps. Interaction energies reveal that adsorption of Li4N on Altop site of Al12P12 results in highly stable structure (isomer J), where superalkali is strongly chemisorbed on the nanocage (Eint. = −105.13 kcal mol−1). Moreover, the lowest HOMO-LUMO gap is also observed for J isomer of Li4N@Al12P12 (0.44 eV), compared to 0.94 eV for alkali metal doped Al12P12 nanocage and 3.36 eV for pure nanocage. Doping of superalkali on aluminum phosphide nanocage can bring considerable increase in first hyperpolarizabilities (βo) response of the nanocage along with deep ultraviolet transparency. The first hyperpolarizability (βo) for isomer J of Li4N@Al12P12 is 6.25 × 104 au. This study may provide an effective strategy to design high performance NLO materials from stable inorganic electrides.

Design and synthesis of high energy density materials is an escalating area of research. Continuous strides are made to explore new and better materials for this purpose. Herein, we report a new and effective strategy to improve the cell voltage and performance of Na-ion batteries where phosphide nanoclusters are doped with endohedral halides. Bare and halide doped boron and aluminum phosphides (BP and AlP) are studied for their applications as electrodes (anodes) in Na-ion batteries. The geometric and electrochemical properties of Na/Na+ with both B12P12 and Al12P12 nanocages are investigated. The interaction energies (Eint.) and frontier molecular orbitals (FMOs) of Na/Na+ ion with B12P12 and Al12P12 nanocages are studied to investigate the effect of neutral or ionic Na on the geometric and electrochemical properties. Bare AlP and BP offer cell voltages of 0.56 and 0.61 V, mainly due to small differences in the interaction energies of Na and Na+ bound systems. The cell voltage is significantly improved by encapsulation of different halide ions into B12P12 and Al12P12 nanocages. Change in Gibbs free energy is significantly improved by the encapsulation of F− into B12P12 and Al12P12 among all considered halides, which results in increase in cell voltage up to 4.5 and 3.5 V for endo-F@B12P12 and endo-F@Al12P12, respectively. This value is higher as compare to cell voltage estimated for carbon nanotubes, functionalized BN nanosheets and B40 fullerenes. The cell voltage of 4.5 V is the highest for any such system. The results here are helpful in designing new materials with even better energy storage density.

Photoswitchable catalysis involves alteration in the intrinsic catalytic properties of an active species through a reversible photochemical transformation. Herein, we report dihydroazulene-vinylheptafulvene (DHA-VHF) based photoswitchable frustrated Lewis pairs (FLPs) for reversible hydrogen activation. The dihydroazulene-vinylheptafulvene moieties here do not act as template to control the catalytic activity, rather the core part of the catalyst. The rational design principle involves evaluation of proton and hydride affinities of Lewis acids (borane) and base (phosphine and amine) functionalities installed on dihydroazulene-vinylheptafulvene photoswitch pair. Significant differences are observed between open VHF and closed DHA for proton and hydride affinities, and these differences are explained by geometric and electronic factors. The individual proton and hydride affinities are utilized to logically formulate best relative positions of both Lewis acid and base on a single molecule in order to activate one H2 molecule per photochrome. For our judiciously designed FLPs, the behavior of phosphine based FLP resembles to that of amine based FLPs at position 2 and 3, however they differ at position 8a. For amine based FLP, the energy released for hydrogen splitting is higher than DHA for all positions (2, 3, 8a) whereas in VHF phosphine based FLP, the energy released on H2 splitting in VHF is lower than that of DHA at position 8a. Moreover, hydrogen splitting is studied on couple of cautiously selected molecules based on the proton and hydride affinities. The activation barriers for hydrogen splitting in VHFs are about 8–10 kcal mol−1 lower than the corresponding barriers in DHAs, chiefly due to the higher hydride and proton affinities.

Due to limitations of fullerene based acceptor molecules for solar cell applications, research is recently diverted to explore non-fullerene acceptor molecules. In this regard, four new A-D-A type fused ring electron acceptor molecules (M1, M2, M3 and M4) are evaluated for their opto-electronic properties for transparent organic solar cells. These molecules contain strong electron donor undecacyclic linked with four different acceptor moieties, 2-(3-ethly-5-methylene-4-oxothiazolidin-2-yluidene)malononitrile (M1), 2-(5,6-dicyano-2-methylene-3-oxo -2,3-dihydroindene-1-ylidene)malononitrile (M2), 2-(5-methylene-6-oxo-tetrahydro-1H-cyclopenta-thiophene-4(5H)-ylidene)malononitrile (M3), and 3-ethyl-5-methylene-2-thioxothiazolidin-4-one (M4). The electronic and optical properties of these molecules are compared with the reference molecule R, which is recently reported as excellent non-fullerene based acceptor molecule. Among all molecules, M2 exhibits the maximum red shift where absorption appears 893.5 nm with B3LYP/6-31++G(d,p) level of theory due to highly extended conjugation between electron withdrawing end-capped acceptor moieties. The calculated Open circuit voltage (Voc) of reference molecule R is 1.78 eV with donor polymer PTB7-Th while molecule M2 exhibits the Voc value of 1.86 eV.

Spectroscopic studies-based on 1D (1H NMR, 13C NMR), 2D-NMR (COSY, HMBC, HSQC), UV–visible, FTIR techniques and quantum chemical studies established on the density functional theory (DFT) were carried out for the natural withanolide glycosides, isolated from Withania Coagulans Dunal. The new glycoside withanolide named as (20R,22R)-14α,17,20β,27-trihydroxy-1-oxowitha-5,24-dienolide-27β-(O-β- d -glucopyranoside) (1), and a known withanolide (20R,22R)-14α-20β,27-trihydroxy-1-oxowitha-5,24-dienolide-3β-(O-β- d -glucopyranoside) (2) are reported here from W. coagulans. The molecular mass of these compounds were confirmed through Fast Atom Bombardment Mass Spectrometry (FAB-MS). Geometric and spectroscopic detailed were obtained from DFT calculations. 1H and 13C NMR theoretical values were found a little higher than the experimental values, but the trend in the chemical shift correlates well with the experimental values. The RMSD values of 1H and 13C NMR of 1 and 2 were 0.4 and 0.38, and 4.94 and 5.02 respectively. The calculated band gap was found 4.93 and 5.00 eV for 1 and 2 respectively which indicated the stable nature of these compounds towards redox reactions.

Alkene is an attractive substrate for chemists due to its easy availability and reactivity towards large number of reactants affording diverse range of organic compounds. It reacts under ionic and free radical mechanisms including single electron transfer (SET). In this review, strategies used for C–C and C-heteroatom functionalization of alkene has been discussed with emphasis on the regio, stereoselectivity, mechanistic detail and sustainability aspects. These strategies mainly follow the free radical mechanism, and the highly reactive carbon radicals show uncontrollable regio- and stereoselectivities. Thus these strategies still need to be focused; especially in the asymmetric versions. The regio- and stereoselectivities of functionalization of alkenes have been highlighted and debated. In addition, the hazardous reagents such as Cl2, Br2 I2, CO, peroxides, and benzene have also been discussed with the emphasis on their impact on the environment. Their plausible green alternatives have also been suggested, such as MX as halogen replacement; CO surrogates (formaldehyde etc.); sustainable aromatic solvents as benzene replacement. The non-green strategies relying on pre-formed silyl hydride and their green alternative strategies such as transfer hydrogenations have also been indicated. The applications of the functionalization of alkenes for the total synthesis of bioactive compounds have also been discussed in detail. In addition, future perspectives are also highlighted for further developments in the functionalization of alkenes.

Though, the gas sensing applications of graphdiyne have widely reported; however, the biosensing utility of graphdiyne needs to be explored. This study deals with the sensitivity of graphdiyne nanoflake (GDY) towards the uric acid (UA) within the density functional framework. The uric acid is allowed to interact with graphdiyne nanoflake from all the possible orientations. Based on these interacting geometries, the complexes are differentiated with naming i.e., UA1@GDY, UA2@GDY, UA3@GDY and UA4@GDY (Figure 1). The essence of interface interactions of UA on GDY is derived by computing geometric, energetic, electronic and optical properties. The adsorbing affinity of complexes is evaluated at ωB97XD/6-31+G(d,p) level of theory. The stabilities of the complexes are quantified through the interaction energies (Eint) with reasonable accuracy. The calculated Eint of the UA1@GDY, UA2@GDY, UA3@GDY and UA4@GDY complexes are -31.13, -25.87, -20.59 and -16.54 kcal/mol, respectively. In comparison with geometries, it is revealed that the higher stability of complexes is facilitated by π-π stacking. Other energetic analyses including symmetry adopted perturbation theory (SAPT0), noncovalent interaction index (NCI) and quantum theory of atoms in molecule (QTAIM) provided the evidence of dominating dispersion energy in stabilizing the resultant complexes. The HOMO-LUMO energies, NBO charge transfer and UV-vis analysis justify the higher electronic transition in UA1@GDY, plays a role of higher sensitivity of GDY towards the π-stacked geometries over all other possible interaction orientations. The present findings bestow the higher sensitivity of GDY towards uric acid via π-stacking interactions.

The sensing affinity of C

Exploring novel nonlinear optical (NLO) materials with excess electron properties is essential for advancing the use of excess electron compounds in optics. The studied superalkali clusters NM

The low concentration of graphene (

In this study, the nonlinear optical (NLO) properties of pristine phosphorene and superalkali (Li3O) doped phosphorene are estimated through the density functional theory (DFT) method to investigate the optical properties. The geometries of complexes have been optimized using the B3LYP/6-31G (d, p) level of theory. The effects of doping on phosphorene have been thoroughly explained by vertical ionization energy (VIE), interaction energies (Eint), and natural bond orbitals (NBO), Moreover, the density of states (DOS), electron density difference map (EDDM) analysis, the frontier molecular orbitals (FMO) plots are also given out to find more physical divination into the electronic communication and structure property relationship. The doping of superalkali conclusively has reduced the HOMO-LUMO energy gap of M1 3.28 eV–1.25 eV for M2 making it the n-type semiconductor. The higher values of Eint, Efm and VIE obtained for M2 has indicated that this complex has higher stability and stronger interaction between superalkalis and phosphorene. More interestingly, there has been a gradual increase in the first static hyperpolarizability (βstatic) values for M1, M2 and M3 are 115.75 au, 4118.6 au, and 659.30 au respectively. The Static second hyperpolarizability (γstatic) of the doped complexes has also been calculated from which the M2 has the highest value of 1382.5 ҳ 103 au. The TD-DFT exploration has exhibited that the doped molecules are adequately transparent in the UV region. Some selected systems are also compared with the p-NA reference molecule which is a familiar external reference molecule for NLO applications. From UV absorption analysis, it can be found that these doped complexes of phosphorene may be contemplated as a new applicant for intense ultraviolet NLO materials. Computational studies have revealed the stability of M2 and M3 making them feasible as NLO materials in optoelectronic applications.

An intriguing class of excess electron oxacarbon superalkali clusters is explored for nonlinear optical response through density functional theory (DFT) methods at CAM-B3LYP/6–311++G(d,p). These superalkali clusters shows noticeable binding energies per atom (Eb) which reveals their thermodynamic stabilities (−86.45 ∼ −119.44 kcal mol−1). The obtained significant VIPs values also suggest the electronic stability of these clusters. The VIP values range from 2.06 eV to 3.42 eV. These clusters show remarkable electronic properties and their HOMO-LUMO gaps (EH-L) are significantly reduced. The lowest H-L gap of 0.96 eV is obtained for C3O3K3 while the highest H-L gap of 2.07 eV is calculated for C3S3Li3. The obtained PDOS spectra further provide evidence for the superior electronic properties of these clusters. The clusters show excellent nonlinear optical properties as revealed from remarkable values (1.6 × 106 au) of static first hyperpolarizability. The controlling factors for hyperpolarizability are also explored by using conventional two-level model. The calculated values of βo are correlated nicely with βtl. The crucial excitation energy is the key factor in controlling the first hyperpolarizability. In these excess electron clusters, the second hyperpolarizability (γo) response increases up to 4.3 × 109 au. Moreover, the calculated scattering hyperpolarizability (βHRS) values are quite significant in these clusters and the highest value of 1.3 × 106 au is calculated for C3S3K3. Additionally, these clusters also possess larger dynamic nonlinearities. The dynamic second hyperpolarizability with dc-Kerr effect increases up to 1.0 × 1011 au. The remarkable values for refractive index (n2) also suggest the excellent nonlinearity of these superalkali clusters.

Finding new materials with exceptionally large nonlinear optical response is an interesting and challenging avenue for scientific research. Here, we report the alkali metal doped Zn

Nonlinear optical materials possess high rank in fields of optics owing to their impacts, utilization and extended applications in industrial sector. Therefore, design of molecular systems with high nonlinear optical response along with high thermodynamic stability is a dire need of this era. Hence, the present study involves investigation of bi-alkali metal doped boron phosphide nanocages M2@B12P12 (M = Li, Na, K) in search of stable nonlinear optical materials. The investigation includes execution of geometrical and opto-electronic properties of complexes by means of density functional theory (DFT) computations. Bi-doped alkali metal atoms introduce excess of electrons in the host B12P12 nanocage. These electrons contribute towards the formation of new HOMO, thus reducing HOMO-LUMO gaps. The reduced HOMO-LUMO gap ranges from 0.63eV to 3.69eV. The diffused excess electrons also come up with increased hyperpolarizability values of complexes i.e. up to 4.0×104au. TD-DFT calculations have been performed to examine crucial transition states and for UV-VIS analysis. IR and DOS spectra have been plotted to support our obtained results. Non covalent interaction (NCI) calculations along with quantum theory of the atoms in molecules (QTAIM) analysis were carried out to understand the bonding interactions between alkali metal atoms and B12P12 nanocage. All obtained results suggest bi-alkali metal doped nanocages as exceptionally stable materials with improved NLO response and superb candidates for their vast applications in optics.

Chemical warfare agents (CWAs) are highly poisonous and their presence may cause diverse effect not only on living organisms but on environment as well. Therefore, their detection and removal in a short time span is very important. In this regard, here the utility of graphdiyne (GDY) nanoflake is studied theoretically as an electrochemical sensor material for the hazardous CWAs including A-230, A-232, A-234. Herein, we explain the phenomenon of adsorption of A-series CWAs on GDY nanoflake within the density functional theory (DFT) framework. The characterization of adsorption is based on optimized geometries, BSSE corrected energies, SAPT, RDG, FMO, CHELPG charge transfer, QTAIM and UV-Vis analyses. The calculated counterpoise adsorption energies for reported complexes range from -13.70 to -17.19 kcal mol-1. These adsorption energies show that analytes are physiosorbed onto GDY which usually takes place through noncovalent interactions. The noncovalent adsorption of CWAs on GDY is also attributed by the SAPT0, RDG and QTAIM analyses. These properties also reveal that dispersion factors dominate in the complexes among many noncovalent components (exchange, induction, electrostatic, steric repulsion). In order the estimate the sensitivity of GDY, the %sensitivity and average energy gap variations are quantitatively measured by energies of HOMO and LUMO orbitals. In term of adsorption affinity of GDY, UV-Vis analysis, CHELPG charge transfer and DOS analysis depict an appreciable response towards these toxic CWAs.

The concern of the present study is to investigate the non-linear optical properties of super halogen doped borophene owing to its broad applications. The first principle study of the material for its non-linear optical properties elaborated its use for electrical and optical applications. The super halogen-based borophene in lithium ion-based batteries and medical appliances have made it one of the most potential materials for optoelectronics. First, hyperpolarizability (βo) of pure and doped B36 is computed and the difference between their values was examined. The vertical ionization energy (VIE) was calculated for pure and doped systems. The interaction energy (Eint) for all combinations was computed. It would be expected to one of the best materials to have high capacity and resistance. For all the calculations and to calculate the HOMO and LUMO energy gap, the density functional theory (DFT) method was used. After observing all the above properties, it was predicted that these combinations are more beneficial and displayed the better nonlinear optical (NLO) for electronic devices.