Supramolecular charge-transfer complex generated by the interaction between tin(II) 2,3-naphtalocyanine as a donor with DDQ as an acceptor: Spectroscopic studies in solution state and theoretical calculations

Abstract

The charge-transfer (CT) phenomenon has attracted the attention of many researchers since it was discovered by Robert Mulliken in 1969. Complexes generated through CT interactions have contributed to industrial processing, technological development, and clinical pharmacology. Here, tin(II) 2,3-naphtalocyanine molecule (termed as SnNc) as a donor was reacted with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as an acceptor in acetonitrile solvent. This yielded a dark brown CT complex formulated as [(SnNc)(DDQ)2]. The resulting CT complex was compositionally (elemental analysis, spectrophotometric titration method, and Job’s continuous variation method), structurally (UV–visible, IR and 1H NMR spectroscopies, and thermal measurements), and theoretically (DFT/TD-DFT calculations) characterized. Electronic charges were transferred from SnNc to DDQ via n → π* transitions in the [(SnNc)(DDQ)2] complex. The experimental data were corroborated with DFT/TD-DFT calculations using B3LYP/LanL2DZ theory level. The energy of the CT reaction and other important parameters were also calculated.