DNA Binding, DFT and Spectroscopic Studies of a Charge Transfer Complex Consisting of a Bioactive Donor 1-(2-Methylbenzyl)piperazine

Abstract

A bioactive donor, 1-(2-methylbenzyl)piperazine is used to synthesize a new charge transfer complex (CTC) with the π-acceptor p-chloranil (p-CHL), which is characterized spectrophotometrically. The quantitative estimation of electronic interaction of the acceptor with the donor has been examined in acetonitrile (AN). The 1:1 composition of the CTC is confirmed by Jobs’ method of continuous variation and spectrophotometric (at $$\lambda$$ max 554 nm) methods at 298 K. The Benesi–Hildebrand method gives the formation constant (KCT) and molar extinction coefficient (e) values of CTC. The spectral analysis was used to characterize CTC and its stability in solution and in the crystalline form. A DNA binding study of the CT-complex was carried out using UV–visible spectroscopy. A density functional theory (DFT) study of the CTC (gas phase/PCM) at using the B3LYP functional and 6-31G(d,p) basis set supports the experimental work. The optimization of the frontier molecular orbital surfaces was carried out by using the DFT-gasphase/PCM correlation methods. Mulliken atomic charges and reactive parameters of acceptor and donor recommend the MBPZ acts as a good electron donor and p-CHL acts as a good electron acceptor to form a highly stable electron transfer complex.