H-bond assisted coordination bond formation in the 1D chains based on azido and phenoxido bridged tetranuclear Cu(II) complexes with reduced Schiff base ligands

摘要

Two new 1D chains [(CuL1R)(2)Cu-2(N-3)(2)(mu(1,1,3)-N-3)(2)](n) (1) and [{(CuL2R)(2)Cu-2(N-3)(2)(mu(1,1,3)-N-3)(2)}center dot(CH3)(2)CO](n) (2) based on rare mu(1,1,3)-N-3 bridged tetranuclear Cu(II) complexes, have been synthesized using [CuL1R] and [CuL2R] as metalloligands [where H2L1R=N,N'-bis(2-hydroxybenzyl)-1,3-propanediamine and H2L2R=N,N'-bis(2-hydroxybenzyl)-1,2-ethylenediamine]. Both complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD, and magnetic study. In case of chain 1, the basic building block is a centrosymmetric tetranuclear unit whereas for 2, it is an asymmetric tetranuclear unit containing two types of square pyramidal Cu(II) centers (terminal and central). The mu(1,1)-N-3 bridged central copper atoms of one tetranuclear unit are connected weakly to the axial position of the terminal copper atoms of neibouring units via the azide ions forming a rare mu(1,1,3)-N-3 bridged novel 1D polymeric chain structure. Variable temperature magnetic susceptibility measurements show the presence of an overall strong antiferromagnetic exchange interactions mediated through the double phenoxido bridges with J values of -123.8 and -144.6 cm(-1) for 1 and 2, respectively. (C) 2017 Elsevier Ltd. All rights reserved.