Synthesis, characterization and structures of copper(II), nickel(II), cobalt(II) and cadmium(II) complexes involving N4-donor ligand and cyanate as coligand: Formation of 1D and 2D crystallographic networks by short intermolecular interactions

Abstract The tetradentate N 4 -coordinate ligand N,N -bis(3,5-dimethyl-1 H-pyrazol-1-yl)methyl-N 2 -phenylethane-1,2-diamine (bdpab) has been used to synthesis a series of four mononuclear complexes of the type [M(bdpab)(NCO)]X [M = Cu(II) and Co(II), X = PF 6 − or ClO 4 − ] and four binuclear NCO − bridged complexes of the formula [M′(bdpab)(μ-NCO)] 2 (X) 2 [M′ = Ni(II) and Cd(II)] and these complexes were characterized by IR, UV–vis, microanalyses and magnetic studies. The structures of four complexes [Cu(bdpab)(NCO)]PF 6 , [Co(bdpab)(NCO)]ClO 4 , [Ni(bdpab)(μ 1,3 -NCO)] 2 (ClO 4 ) 2 and [Cd(bdpab)(μ 1,1 -NCO)] 2 (ClO 4 ) 2 have been solved by single crystal X-ray diffraction studies. The structural data reveals that mononuclear [Cu(bdpab)(NCO)]PF 6 and [Co(bdpab)(NCO)]ClO 4 complexes have distorted square pyramidal geometry whereas binuclear double end-to-end NCO bridged nickel(II) complex [Ni(bdpab)(μ 1,3 -NCO)] 2 (ClO 4 ) 2 and binuclear double end-on NCO bridged cadmium(II) complex [Cd(bdpab)(μ 1,1 -NCO)] 2 (ClO 4 ) 2 have distorted octahedral geometry. Hydrogen bonding, CH–π interaction and π–π stacking between phenyl ring and one pyrazole ring have been observed in all the complexes and they are assembled to form 1D and 2D crystallographic networks.