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

New anthracene-based Ni(II) thiosemicarbazones with novel intramolecular π–π stackings have been prepared. The interactions are manifested via the unsual 1HNMR signal pattern and the broadening of absorption and emission bands of the complexes. [Display omitted] •Anthacene-based Ni(II) thiosemicarbazones show novel intramolecular π–π stackings.•Some of 1H NMR signals are not found and largely shifted due to diatropic effect.•Severe broadening of absorption and emission bands reveals electronic perturbation. 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.