Abstract Two independent σ ‐ and π substituent effect descriptors, s EDA p EDA, were constructed using the Natural Population Analysis (NPA) approach. The descriptors are based on parameters of 32 monosubstituted benzene molecules calculated at B3LYP/6‐31G** level which is easily applicable to large molecular systems. have a clear physical meaning—they show what extent electrons donated or withdrawn by from substituted system. successfully tested be either theoretical methods (DFT MP2),...

The application of ab initio and DFT computational methods at six different levels theory (MP2/cc-pVDZ, MP2/aug-cc-pVTZ, B3LYP/cc-pVDZ, B3LYP/aug-cc-pVTZ, M06/cc-pVDZ, M06/aug-cc-pVTZ) to meta- para-substituted fluoro- trifluoromethylbenzene derivatives 1-fluoro- 1-trifluoromethyl-2-substituted trans-ethenes allowed the study changes in electronic geometric properties F- CF3-substituted systems under impact other substituents (BeH, BF2, BH2, Br, CFO, CHO, Cl, CN, F, Li, NH2, NMe2, NO, NO2,...

Theoretical studies were carried out on two pairs of americium and europium complexes formed by tetra-N-dentate lipophilic BTBP ligands, neutral [ML(NO3)3] cationic [ML2]3+ where M = AmIII or EuIII, L 6,6′-bis-(5,6-diethyl-1,2,4-triazin-3-yl)-2,2′-bipyridine (C2-BTBP). Molecular structures the have been optimized at B3LYP/6-31G(d) level total energies in various media estimated using single point calculations performed B3LYP/6-311G(d,p) MP2/6-311G(d,p) levels theory. In ions treated...

Eight-membered 10π heterocyclic mesomeric betaines (HMBs) are unusual in that they associated with two 1,3-dipolar fragments mutual conjugation; conjugated HMBs belonging to Class 1A. Apart from the characterization of five derivatives 1,5-dithia-2,4,6,8-tetrazocine ring 1980s, this large family "aromatic" heterocycles has received no attention. The density functional theory (DFT) study reported here investigates structure, aromaticity, and bonding representative examples. parent structures...

Fulvene is a non-aromatic molecule, but variation of the electron-donating/withdrawing power substituents exo to five-membered ring can drive system between extremes aromatic and antiaromatic, as judged by prediction fully developed diatropic paratropic currents through ab initio calculations made at ipsocentric 6-31G**/CTOCD-DZ CHF level.

Palladium(II) complexes attract great attention due to their remarkable catalytic and biological activity. In the present study X-ray characterization, UV-Vis Time-Dependent Density Functional Theory (TD-DFT) calculations for six PdCl2(XPy)2 (where: Py = pyridine; X H, CH3 or Cl) were applied in order investigate substituent effects on crystal structures electronic properties combine results with cytotoxic The of PdCl2(3-MePy)2, PdCl2(4-MePy)2 PdCl2(2-ClPy)2, have been described first time...

An energy-based index of the ease N-heterocyclic carbene (NHC) formation either by deprotonation precursor salts to give neutral NHCs or heterocyclic mesomeric betaines anionic is described. This (CREF; Carbene Relative Energy Formation), which easily calculated using DFT methods, also gives a quantitative measure relative σ-donor strength NHCs. CREF values for wide range known and unknown NHC ring systems are reported their significance discussed.

At the B3LYP/6-311++G(d,p) level, approach of a lithium atom to face fulvene molecule leads formation complex with binding energy 41 kcal/mol and significant ion-pair character. The moiety gains delocalized aromatic cyclic π system, documented by geometry-based aromaticity index HOMA, strong diatropic ring current, visualized ipsocentric calculation current-density, which an "aromatic" NICS value −11 ppm.

The index described previously (carbene relative energy of formation) has been extended to oxygen and sulfur heterocycles. This provides a quantitative overview factors determining ease formation (i) neutral N-heterocyclic carbenes (NHCs) by deprotonation heterocyclic salts (ii) anionic NHCs mesomeric betaines. influence the nature ring position is discussed for range known unknown systems. Attention directed unexplored systems potential interest.

A complete set of azoles undergoing 1,2-proton transfer, consisting pyrazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole and pentazole, was computationally investigated regarding proton transfer mechanism in gas phase water solution. Complexes one azole molecule with 1–4 molecules were employed to facilitate the by lowering activation energy, which for isolated is prohibitively large. The calculations performed at MP2/aug-cc-pVDZ B3LYP/6-311++G(d,p) levels theory showed very good concordance....

The Π-electron delocalization of mono-derivatives benzene as well penta- and heptafulvenes was analyzed based on quantum chemistry approach in the gas phase five polar environments increasing polarity. most representative aromaticity indices were selected by aid Principal Component Analysis, which reduces initial set 32 to orthogonal comprising FLU1/2 index, pEDA Laplacian estimated at ring critical point (RCP(∇2Ρ)). These used for description substituent effect non-polar conditions. A...