(Isocyano group)⋯lone pair interactions involving coordinated isocyanides: experimental, theoretical and CSD studies

Both carbon and nitrogen centers in the coordinated isocyano group are capable of acting as a π-hole donor toward lone pairs.

Vibrational Spectra, DFT Calculations, Electronic and Optical Properties of 3-bromo-o-xylene

The vibrational spectra of 3-bromo-o-xylene have been studied by FTIR and FT-Raman spectra in the regions 4000-400 cm-1 and 3500-50 cm-1 , respectively. The geometrical parameters, frequencies and spectral intensities were calculated by density functional theory (DFT/B3LYP) method with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The experimental and theoretical spectra are compared. The UV–Vis spectral analysis and the HOMO-LUMO of the molecule has been calculated which confirms the charge shift of the molecular system. The natural bond orbital investigation has been found for different bonding, antibonding and lone pair interactions and mapped molecular electrostatic potential (MEP) have also been reported

Sulfur(lone-pair)…π interactions with FAD in flavoenzymes

The interactions of π-systems with lone-pairs of electrons are known and have been described in biological systems, involving lone-pairs derived from metals, metalloids, sulfur, oxygen and nitrogen. This study describes a bibliographic survey of the disulfide-bound sulfur(lone-pair) interactions with π-systems residing in the flavin adenine dinucleotide (FAD) cofactor of oxidoreductase enzymes (flavoenzymes). Thus, of the 172 oxidoreductase enzymes evaluated for gamma-S(lone-pair)…π(FAD) interactions, 96 proteins (56%) exhibited these interactions corresponding; 61% of 350 the constituent monomers featured at least one gamma-S(lone-pair)…π(FAD) interaction. Two main points of association between the S(lone-pair) and the isoalloxazine moiety of FAD were identified, namely at the centroid of the bond linking the uracil and pyrazine rings (60%), and the centroid of the uracil ring (37%). Reflecting the nature of the secondary structure in three prominent classes of oxidoreductase enzymes: glutathione disulfide reductases (GR; 21 proteins), trypanothione disulfide reductases (TR, 14) and sulfhydryl oxidases (SOX, 22), the approach of the gamma-S(lone-pair) to the FAD residue was to the si-face of the isoalloxazine ring system, i.e. to the opposite side as the carbonyl residue, for all GR and TR examples, and to the re-face for all SOX examples. Finally, the attractive nature of the gamma-S(lone-pair)…π(FAD) interactions was confirmed qualitatively by an examination of the non-covalent interaction plots.

The influence of intramolecular sulfur–lone pair interactions on small-molecule drug design and receptor binding

Sulfur–lone pair interactions are important conformational control elements in sulfur-containing heterocycles that abound in pharmaceuticals, natural products, agrochemicals, polymers and other important classes of organic molecules.

Band gap engineering of bulk and nanosheet SnO: an insight into the interlayer Sn–Sn lone pair interactions

The effects of interlayer lone-pair interactions on the electronic structure of SnO are explored using density-functional theory.