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

Abstract Two new 1D chains [(CuL 1R ) 2 Cu 2 (N 3 ) 2 ( μ 1,1,3 -N 3 ) 2 ] n ( 1 ) and [{(CuL 2R ) 2 Cu 2 (N 3 ) 2 ( μ 1,1,3 -N 3 ) 2 }·(CH 3 ) 2 CO] n ( 2 ) based on rare μ 1,1,3 -N 3 bridged tetranuclear Cu(II) complexes, have been synthesized using [CuL 1R ] and [CuL 2R ] as “metalloligands” [where H 2 L 1R  = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine and H 2 L 2R  = 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 μ 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 μ 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.