The polyphenyl chains with $n$ hexagons are the special graphs of unbranched polycyclic aromatic hydrocarbons. The objective of this study is to find the expected values of the multiplicative version of the atomic-bond connectivity index and geometric-arithmetic index of this class of special hydrocarbons. The average values of these two indices with respect to the set of all polyphenyl chains have been determined. Finally, the comparisons between the expected values of the aforementioned indices in the random polyphenyl and spiro chains, have been outlined.

In the current research chor, we are reporting the synthesis of 2-amino-6-methylpyrimidin-4-yl benzenesulfonate (AMPBS) and 2,6-diaminopyrimidin-4-yl benzenesulfonate (DAPBS) via O-benzenesulfonylation of 2-amino-6-methylpyrimidin-4-ol 1 and 2,6-diaminopyrimidin-4-ol 2 respectively. The structures of the synthesized compounds were characterized unambiguously by single crystal analysis (SC-XRD).Hirshfeld surface study showed that C-H…O, C-H…N and especially C-H…C hydrogen bond interactions are the key contributors to the intermolecular stabilisation in the crystal. The quantum chemical understanding about optimized geometry, natural bond orbitals (NBOs), frontier molecular orbitals (FMOs) and nonlinear optical (NLO) analysis for AMPBS and DAPBS were obtained by applying density functional theory (DFT) at B3LYP level and 6-311G(d,p) basis set. Time dependent density functional theory (TD-DFT)/ B3LYP/ 6-311G(d,p) level were employed to determine the photo physical properties of compounds. As a whole, the simulated results were found to have an excellent concurrence to the experimental results. The charge transfer phenomenon entitled compounds was determined by FMOs. Global reactivity parameters were obtained by using HOMO–LUMO energies of compounds. Overall, the computational results of AMPBS and DAPBS have outstanding agreement to experimental data. The computational study also showed that the title compounds have remarkable NLO properties.

L-lysine amino acid is cocrystallized with L-mandelic acid by the slow evaporation method. Single crystal X-ray analysis reveals that lysine-mandelic acid crystallized as a dihydrate form. In the crystalline state, the lysine molecule exists in the cationic form in which the backbone and side chain amino groups are protonated and the carboxylic acid is deprotonated. The carboxylic acid proton of the mandelic acid is transferred to the lysine side chain and thus carries a negatively charged ion. The lattice water molecules are located near the amino groups of the lysine. Intermolecular interactions formed between lysinium, mandelate and lattice water molecules are qualitatively analyzed using Hirshfeld surfaces and 2D-fingerprint plots. The energetics of different dimeric complexes is quantitatively analyzed using PIXEL energy analysis. Topological parameters derived from QTAIM framework are used to delineate the nature of different intermolecular interactions formed in the title complex.

This DFT study treats thermal metal-catalyzed alkene aziridination by azides, where the catalysts are copper(II) triflate, cobalt(II) porphin and ruthenium(II) porphin. Three azides RN3 (R = H, Me, Ac) react with alkene substrates in the presence of these catalysts leading to aziridine formation by a two-step catalysed mechanism. In Step I, the azide reacts with the catalyst to first form a metal nitrenoid via transition state TS1. The Ru(porph) catalyst is particularly effective for Step I. In Step II, the metal nitrenoid adds to the alkene via TS2 giving the aziridine product. Cu(trfl)2 is most effective as a catalyst for Step II. The facility order H > Me > Ac (with respect to the azide R group) holds for Step I, and the reverse order for Step II. Transition states TS1 and TS2 are described as “early” and “late”, respectively, in good accord with Hammond’s postulate.

A combined experimental work and molecular electron density theory (MEDT) analysis was performed to reveal the strict click of 1,2,3-triazole derivatives by Ag(I)-catalyzed azide-alkyne cycloaddition (AgAAC) reaction and its corresponding mechanistic pathway. Such straightforward protocol for the click formation of 1,4-disubstituted-1,2,3-triazoles makes use of AgCl as catalyst in water as solvent under ambient conditions., with excellent yields and simple experimental work-up. MEDT study was performed by using DFT calculations at the B3LYP/6-31G(d,p) (LANL2DZ for Ag) level in order to understand the observed regioselectivity in AgAAC reactions, and to delineate the number of silver(I) species and their roles in this clickable 1,2,3-triazole formation. The comparison of the mononuclear Ag(I)-acetylide and binuclear Ag(I)-acetylide in the AgAAC reaction paths concerning the AgAAC reactions, shows that the values of the energy barriers for the binuclear processes are smaller than that of the mononuclear one. The intramolecular nature of these AgAAC reactions accounts for the regioselective formation of the 1,4-regiosisomeric triazole derivatives. The ionic nature of the starting metallated species is revealed for the first time, ruling out any covalent interaction involving the silver(I) complexes throughout the reaction as supported by the ELF topological analysis of the electronic structure of the stationary points, reaffirming the zw-type mechanism of the AgAAC reactions.