Geometric (HOMA) and magnetic (NICS) indices of aromaticity were estimated for aromatic rings of amino acids and nucleobases. Cartesian coordinates were taken directly either from PDB files deposited in public databases at the finest resolution available (≤ 1.5 Å), or from structures resulting from full gradient geometry optimization in a hybrid QM/MM approach. Significant environmental effects...

The effects of atmospheric nitrogen (N) deposition on organic matter decomposition vary with the biochemical characteristics of plant litter. At the ecosystem-scale, net effects are difficult to predict because various soil organic matter (SOM) fractions may respond differentially. We investigated the relationship between SOM chemistry and microbial activity in three northern deciduous forest e...

The computational insights illustrate the intramolecular hydrogen bonding/stability versus aromaticity analyses of a variety several sets multi-substituted OH/SH benzenes using quantifying approaches (NICS, HOMA, PDI, and AIBIC for aromaticity) (Relative Energy, HOMO-LUMO gap, QTAIM, HBSBIC stability/hydrogen bond strength) in framework density function theory (DFT) approach ab initio calculati...

The ascertainment of magnetic aromaticity is not necessarily straightforward, especially for large and bent systems, such as the cycloporphyrin nanorings recently synthesized by group Anderson. Six these were studied here computationally. Indirect methods, based on nuclear shielding magnetizabilities, direct standard quantum mechanics, both used effectively to determine their magnetically induc...

Carbon nanotubes are composed of cylindrical graphite sheets. Both nanotubes and graphite sheets are benzenoid derivatives composed of sp2 carbon atoms arranged in a hexagonal pattern. Therefore both systems are aromatic. The extent of the aromatic character of a molecule G (here benzenoids) can be explained in terms of the number of possible Kekulé structures in G. In this work the Kekulé stru...

Aromaticity, a very important term in organic chemistry, has never been defined unambiguously. Various ways to describe it come from different phenomena that have experimentally observed. The most examples related some theoretical concepts are presented here.