Crystal structure and quantum chemical calculations of (E)1‐benzyl‐3‐((4‐methoxyphenyl)imino)‐5‐methylindolin‐2‐one

Abstract

The known Schiff base compound, (E)1‐benzyl‐3‐((4‐methoxyphenyl)imino)‐5‐methylindolin‐2‐one, was prepared as before by reacting 1‐benzyl‐5‐methylindoline‐2,3‐dione with 4‐methoxyaniline. The product was unambiguously characterized using elemental analysis, 1H and 13C‐NMR spectroscopy, and its new single‐crystal X‐ray structural analysis. Molecular orbital calculations were conducted in order to investigate the structures and relative stabilities of the (E) and (Z) isomers of 1‐benzyl‐3‐([4 methoxyphenyl]‐imino)‐5‐methylindolin‐2‐one. Specific attention was paid to the (E) isomer. The available crystallographic experimental data for the latter ensured also validation of the model structures computationally derived at the theoretical B3LYP/6‐31G(d,p) level.

A computational quantum chemical study of fluorinated Allopurinol

“…Higher HOMO energy means a stronger ionization potential of the compound (6). The energy gap between the HOMOs and LUMOs is the critical parameter in determining the molecular electrical transport properties which help in the measure of electron conductivity (7). This energy gap is also related to the chemical hardness, stability, and reactivity of a compound (5,8).…”

“…In addition, a larger energy gap means a smaller aromatic system (6) and chemically a harder compound (5). In most of the traditional and feasible nitrogen-based drugs, the range of HOMO-LUMO energy gap is within 3.5-4.5 eV (5,(7)(8)(9)(10)(11)(12). Thus, we can assume that drug compounds with a HOMO-LUMO gap around this range contain proper stability and reactivity.…”