Dinuclear nickel complexes of phenolbased dinucleating macrocycles: Synthesis, structure, and properties

Abstract

Abstract Dinuclear Ni2(II,II) complexes with the formula [Ni2(Rm,n)](ClO4)2 ((m,n)= (2,2) (1), (2,3) (2), (2,4) (3)) have been obtained where (Rm,n)2- denotes the macrocycles containing two 2,6-bis(iminomethyl)-4-methylphenolate entities combined through two lateral chains, -(CH2)m- and -(CH2)n-, at the imino nitrogens. [Ni2(R2,2)](ClO4)2 (1) crystallizes in the triclinic crystal system, space group P 1, with Z=1, a=8.396(2) A, b= 10.021(2) A, c=8.104(2) A, α=109.56(2)°, β=99.40(2)°, γ=79.89(2)°, V=628.5(3) A3 and Z=1. The refinement converges with R=0.0384 and Rw=0.0415 for 2075 reflections with | Fo | > 3[sgrave](| Fo |). In the centrosymmetric [Ni2(R2,2)]2+, a pair of Ni(II) ions are bridged by two phenolic oxygens with the Ni···Ni separation of 2.801(1) A. Each Ni assumes a planar configuration with Ni-O bond distances of 1.842(3) and 1.838(3) A and Ni-N bond distances of 1.814(3) and 1.823(3) A. In the solid state, 1 is diamagnetic (S1=S2=0) whereas [Ni2(R2,3)]-(ClO4)2 (2) and [Ni2(R2,4)](ClO4)2 (3) ...