Crystal structure and electrochemical properties of [Ni(bztmpen)(CH3CN)](BF4)2 {bztmpen is N-benzyl-N,N′,N′-tris[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine}

The mononuclear nickel title complex (acetonitrile-κN){N-benzyl-N,N′,N′-tris[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine}nickel(II) bis(tetrafluoridoborate), [Ni(C30H35N5)(CH3CN)](BF4)2, was prepared from the reaction of Ni(BF4)2·6H2O with N-benzyl-N,N′,N′-tris[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine (bztmpen) in acetonitrile at room temperature. With an open site occupied by the acetonitrile molecule, the nickel(II) atom is chelated by five N-atom sites from the ligand and one N atom from the ligand, showing an overall octahedral coordination environment. Compared with analogues where the 6–methyl substituent is absent, the bond length around the Ni2+ cation are evidently longer. Upon reductive dissociation of the acetronitrile molecule, the title complex has an open site for a catalytic reaction. The title complex has two redox couples at −1.50 and −1.80 V (versus Fc+/0) based on nickel. The F atoms of the two BF4− counter-anions are split into two groups and the occupancy ratios refined to 0.611 (18):0.389 (18) and 0.71 (2):0.29 (2).