Synthesis, Characterization and Crystal Structures of Four Dinuclear Schiff Base Nickel(II) and Copper(II) Complexes with Versatile Bridging Groups

Abstract

AbstractFour novel Schiff base nickel(II) and copper(II) complexes, derived from the end‐on (μ1,1‐N3) azide, end‐to‐end (μ1,3‐NCS) thiocyanate, or phenolate oxygen bridges, have been synthesized and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Ni2(L1)2(MeCN)2(μ1,1‐N3)2]·MeOH (1), the dinuclear double end‐on azide‐bridged [Ni2(L2)2(MeOH)2(μ1,1‐N3)2][Ni2(L2)2(OH2)2(μ1,1‐N3)2]·MeOH (2), the dinuclear double end‐to‐end thiocyanate‐bridged [Cu2(L3)2(μ1,3‐NCS)2] (3), and the dinuclear double phenolate O‐bridged [Cu2(L4)2(NCS)2] (4), where HL1, HL2, HL3 and HL4 are four tridentate Schiff bases obtained by the condensation of 3,5‐dibromosalicylaldehyde with N‐ethylethane‐1,2‐diamine, of 3,5‐dichlorosalicylaldehyde with N‐methylpropane‐1,3‐diamine, of 3‐bromo‐5‐chlorosalicylaldehyde with 2‐aminomethylpyridine, and of 5‐nitrosalicylaldehyde with 2‐aminomethylpyridine, respectively. Each nickel(II) atom in 1 and 2 is in an octahedral coordination, while each copper(II) atom in 3 and 4 is in a square pyramidal coordination. There exists crystallographic inversion centre symmetry in each of the complexes.