Anthracene-based Ni(II) thiosemicarbazones with novel intramolecular π–π stackings

Abstract

Four new Ni(II) complexes were obtained from the reaction between anthracene-based thiosemicarbazones and inorganic metal salt. Structural investigation of the complexes using X-ray crystallography reveals unusual cis geometries driven by intramolecular π–π stackings between anthracenyl rings. Due to the novel interactions, the anthracenyl protons H1,8,2,7 are not observed and the imine proton is largely shifted in 1H NMR spectra. The UV–Vis and photoluminescent data clearly indicate strong perturbation of intramolecular π–π stackings on electronic structure of anthracenyl cores, namely broadening of absorption and emission bands.