In an attempt to diversify the options in designing graphene-based systems bearing large second order nonlinear optical (NLO) responses of octupolar and/or dipolar character, subject quadratic NLO properties hybrid boron nitride (BN) graphene flakes is opened up. State art ab initio and density functional theory methods applied on a toolbox book-text arbitrary planar h-BN-graphene nanosized reveal that by confining finite h-BN sections internal network graphene, capacity π-electron species...

On the basis of quantum chemical calculations, radical-scavenging property attributed to anthocyanidins was analyzed considering three mechanisms: hydrogen atom transfer (HAT), stepwise electron-transfer-proton-transfer (ET-PT), and sequential proton loss electron (SPLET). We found that activity mechanism through which they react are pH-dependent, because diverse colorful forms in may exist prototropic equilibria (cationic, neutral, anionic) susceptible experience each mechanisms proposed....

When inorganic benzene is confined in the honeycomb structure of nanographenes, it triggers impressive NLO variations powered by local electron delocalization effects.

Within the realm of hybrid materials built from graphene and white (hexagonal boron nitride (h-BN)), this paper attempts to shed light on some unknown aspects concerning essential structure–property relationships one might come across in h-BN/graphene hybrids finite size. To do so, we present analyze outcomes a systematic study focalized electric properties and, more particularly, microscopic dipole polarizabilities first hyperpolarizabilities purposely chosen nanosized molecular comprising...

Activating and deactivating abilities of several substituents (-CH3, -F, -NH2, -NO2) in indole have been theoretically studied using a series electron density based reactivity indices. Calculations performed at the B3LYP/6-311++G(2d,2p) level. An energetic criterion on proton affinities (PAs) has employed to check validity these Relative PAs reflect ortho para orientation ability -CH3, -NH2 groups, whereas large effect -NO2 is mainly observed positions. Also, substitutions carbons 2 6 (IUPAC...

Several measures of aromaticity including energetic, magnetic, and electron density criteria are employed to show how aromatic stabilization can explain the stability sequence hydroporphyrins, ranging from porphin octahydroporphin, their preferred hydrogenation paths. The methods involve topological resonance energies circuit energy effects, bond energies, multicenter delocalization indices, ring current maps, magnetic susceptibilities, nuclear-independent chemical shifts. To compare...

In this work, a general scheme to visualize polarizability density distributions is proposed and implemented in Hirshfeld-based partitioning scheme. This allows us obtain easy-to-interpret pictorial representations of both total intrinsic polarizabilities where each point the formed by contribution any atom or group atoms molecule. addition, procedure used here permits possibility removing size dependence electric-dipole polarizability. Such development opens new horizons exploring...

Hybrid graphene/(hexagonal-boron-nitride) systems start to play a pivotal role in the realm of two-dimensional materials for atomically thin integrated circuits. As result, there is significant interest fabricating BnNn-substituted graphene networks from bottom-to-up be used as precursors flexible one-atom thick electronic and optical devices. In this report, we present piece theoretical work dealing with microscopic dipole–dipole polarizabilities (static dynamic) borazine (B3N3) doped...

The main goal of this study was the design/recognition a series derivatives with exceptionally large hyperpolarizabilities, understanding mechanism through which these properties are derived, and generalization resulting findings. Thus, we have studied structure, involving excitation energies diradical character, but mainly (hyper)polarizabilities some oligomers radiaannulene-tetrathiafulvalene (RA-TTF), radiaannulene-bis(ethylene-1,2-dithiolato)nickel (RA-NiBDT), their lithiated analogues....

Within an attempt to unravel the conundrum of irregular bandgap variations in hybrids white-graphene (hBN) and graphene (G) observed both experiment theory, strong proofs about decisive role aromaticity their electronic properties are brought light. Sound numerical experiments conducted on zero-, one- two-dimensional hBNG demonstrate that upon structural and/or perturbation caused by foreign doping agents, uniformity local cyclic electron delocalization ideal restructures locally creating...

A systematic analysis of the molecular structure, energetics, electronic (hyper)polarizabilities and their interaction-induced counterparts C60 with a series graphene (MG) models, CmHn, where m = 24, 84, 114, 222, 366, 546 n 12, 30, 42, 54, 66, was performed. All reported data were computed by employing density functional theory basis sets. The main goal study is to investigate how alteration size MG model affects strength interaction, charge rearrangement, polarization complex, C60-MG....

The analysis of previously reported shortcomings the condensed Fukui functions obtained making use quantum theory atoms in molecules indicates these drawbacks are due to inadequacy definition employed compute them and not partitioning. A new procedure, which respects mathematical solves problems, is presented for calculation atomic basins defined according molecules. It tested a set 18 molecules, includes most controversial cases.

The stability and electron density topology of catechol complexes (dimers tetramer) were studied using the MPW1B95 functional. QTAIM analysis shows that both dimers (face to face C-H/pi one) display a different electronic origin. formation former is accompanied by significant change in values atomic dipole quadrupole components, flattening most diffuse part distribution toward molecular plane. A small population transfer observed between monomers connected interactions, whose...

A quantum theory of atoms in molecules-based energy partitioning was carried out for Z and E conformers a series O=C-X-R containing compounds. The results obtained the simplest compound (formic acid) indicate that attraction electron density within carbonyl oxygen by nucleus acid hydrogen is most important term preference. This conclusion can be extended (mutatis mutandis) to larger carboxylic acids, esters, sulfur derivatives, secondary amides, isocyanates, even explains sequence relative...

Design of efficient photonic materials with exceptionally large nonlinearities: linear and planar oligomers based on nickel bis(dithiolene) π-electron linkers.

Using coupled-perturbed theory the same excited state/orbital analysis as sum-over-states method may be performed.

Starting from a hypothetical but fundamental charge/discharge sequence, the topic of nonlinear optical switching in atomic clusters built silicon and alkali metals is opened up. The outcomes presented this work, obtained with ab initio methods exceptional predictive capabilities, offer strong evidences that sizable hyperpolarizability contrasts between neutral charged metal doped cluster forms might be simultaneously accomplished. observed procedure involves redox polyatomic formed by Si...

The impact of the solvent environment on stabilization complexes formed by fluorine (T-F) and cyanide (T-CN) substituted tweezers with halide anions has been investigated theoretically. study was carried out using computational methodologies based density functional theory (DFT) symmetry adapted perturbation (SAPT). Interaction energies were obtained at M05-2X/6-31+G* level. results show a large stability in solvents dielectric constant prove suitability these molecular as potential hosts...

A discussion about the negative sign of sizable static second hyperpolarizability a short zigzag graphene ribbon (C60H20) reported in G.-L. Chai, C.-S. Lina and W.-D. Cheng, J. Mater. Chem., 2012, 22, 11303 is presented. As shown, closed-shell singlet configuration specific as described by approximate methods HF DFT causes serious side effects on computations electric response properties such dipole polarizabilities hyperpolarizability.

The synthesis and optoelectronics properties of polyaromatic hydrocarbons (PAHs) doped with boron nitrogen units (BN) monopolize the interest increasing numbers researchers past few years. key concept fueling these attempts lies on prospect engineering novel organic compounds versatile physical chemical using well-known all-carbon systems as scaffolds. Among various BN-doped PAHs synthesized so far, one could distinguish two categories. most common comprises in which BN replace aromatic CC...

Abstract Basic processes for the ionic chemistry of 1,3‐azoles (protonation, nitration, hydride addition, and deprotonation) have been studied by analyzing B3LYP/6‐311++G(2d,2p) 6d electron densities using Quantum Theory Atoms in Molecules (QTAIM) delocalization indices gas phase aqueous solution modeled with Polarizable Continuum Model (PCM) method. The most stable protonation site is N3 all cases, this takes place without a significant change delocalization, whereas C5 preferred...