Synthesis, experimental characterization and theoretical calculation of novel charge transfer complex between (S, S)-bis-N,N-sulfonyl bis -L-phenylalanine dimethylester and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)

Charge transfer complex (CTC) formed between (S, S)-bis-N, N-sulfonyl bis-L-phenylalanine dimethy-lester as donor and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as acceptor, has been studied spectrophotometrically. Benesi-Hildebrand and molar ratio methods were applied in order to determine association constant (K-CT), molar extinction coefficient (epsilon(CT)) and stoichiometric ratio, respectively. The solid CT complex has been synthesized and its structure was characterized via spectroscopic techniques (UV-vis and FT-IR). In order to determine the equilibrium geometries, DFT/CAM-B3LYP has been employed. Moreover, TD-DFT method was used to investigate the electronic structures of donor, acceptor and their complex. Natural bond orbital (NBO) analysis has been used to study the atomic charges and molecular bonding interactions of the interesting complex. These studies show that non-bonding interactions are important in charge transfer complex. (C) 2019 Elsevier B.V. All rights reserved.