A new dinuclear copper(II) complex of a bis-macrocyclic ligand: Synthesis, characterization, crystal structure and magnetic properties

A new dinuclear Cu(II) complex, [Cu2L(N-3)(2)] (ClO4)(1.5) . (OH)(0.5) . 2H(2)O . 0.5C(2)H(5)OH (1), of a bis-macrocyclic ligand, 2,6-bis(1, 4, 7, 10-tetraazacyclododecan-10-ylmethyl)-methoxybenzene (L), has been synthesized, characterized and structurally determined by X-ray diffraction analysis. Complex 1 crystallizes in orthorhombic crystal system, Pca2(1) space group with a = 1.5371(3), b = 1.6641(3), c = 3.0950 (6) nm, V = 7.917 (3) nm(3), F-w = 904.62, Z = 8, D-c = 1. 529 g/cm(3), and final R = 0. 0568, wR = 0. 1406 for 10410 observed reflections with I greater than or equal to 2 sigma (I). Both Cu(II) centers in the structure are coordinated by four nitrogen atoms of 1, 4, 7, 10-tetraazacyclododecane (cyclen) and a nitrogen donor of the axial azide anion. Each Cu (H) center is in a square-pyramidal coordination environment, and the intra- and nearest inter-molecular Cu . . . Cu nonbonding distances are 0.9855 and 0.7298 run, respectively. Variable temperature magnetic susceptibility measurements in the range of 4.2-300 K indicate that there exists weak intra- and inter-molecular antiferromagnetic coupling between the Cu(H) centers with 2J = -4.2 cm(-1) and Theta = - 0.47 K.