Syntheses and Crystal Structures of Two Novel Linear Trinuclear Schiff Base Nickel(II) and Cadmium(II) Complexes

Two novel linear trinuclear Schiff base complexes, [Ni{Ni(C 17 H 14 Br 2 N 2 O 2 )(NO 3 )(H 2 O)} 2 ] · 2MeOH · 2H 2 O ( 1 ), and [Cd{Ni(C 25 H 20 N 2 O 2 )(CH 3 COO)} 2 ] ( 2 ), were synthesized and characterized by elemental analyses, infrared spectroscopy, and X‐ray single crystal determinations. There are three bridges across the Ni‐M atom pairs (M is Ni for 1 , and Cd for 2 ) in each complex, involving two phenolate O atoms of a Schiff base ligand ( N , N′ ‐bis(5‐bromosalicylidene)‐1,3‐propanediaminate (BSPD) for 1 and N , N′ ‐bis(2‐hydroxynaphthylmethenylimino)‐1,3‐propanediaminate (HNPD) for 2 ), and an O‐N‐O moiety of a μ ‐nitrato group for 1 or an O‐C‐O moiety of a μ ‐acetato group for 2 . In each of the complexes, the central M 2+ is located on an inversion center and has an octahedral coordination involving four bridging O atoms from two Schiff base ligands in the equatorial plane and one O atom from each bridging nitrate or acetate group in the axial positions. The coordination around the terminal Ni 2+ ions is also octahedral for 1 , but square pyramidal for 2 . The nitrate or acetate bridges linking the central and terminal metal ions are mutually trans . The Ni···M distances are 3.006(2) Å in 1 , and 3.175(2) Å in 2 .