Synthesis and spectral studies of Ni(Ⅱ) complexes involving functionalized dithiocarbamates and triphenylphosphine: X-ray crystal structure, thermal stability, Hirshfeld surface analysis, DFT and biological evaluation

•Four Ni(II) complexes containing dithiocarbamate and phosphine ligands were prepared.•Complexes were characterized by IR, UV–vis, NMR and TGA.•Single crystal X-ray diffraction and DFT studies on complex 3 were performed.•Optimized bond parameters agree well with the experimental results.•DNA binding, antioxidant and antifungal screening have proven the compounds to be bioactive.