Synthesis, crystal structure and magnetic properties of a new dicopper(II)complex with a bis(macrocyclic) ligand

A new binuclear copper(II) complex, [Cu2LBr2]Br . 3H(2)O, where L is a new binucleating macrocyclic ligand 2, 6-bis(1,5,9-triazacyclododecan-9-ylmethy l) benzoate, has been prepared and characterized by X-ray crystallography. Crystal data: monoclinic,space group P2(1)/c, a = 1.1666(2), b = 1.3541(3), c = 2.2750(5)nm, beta = 99.38(3)degrees, Z = 4. The binuclear copper( Il) center ions are bridged by a mu-carboxyl group of L and separated by 0.5884 nm. Both of the copper(II) ion centers are coordinated by three amine nitro gens of [12]aneN(3) subunit and one oxygen of the carboxyl group,as well as one bromide ion. The copper( IT) ion is in the trigonal bipyramid environm ent. Variable temperature magnetic susceptibility studies indicate that the re exists intramolecular antiferro - magnetic coupling (J = - 22.49cm(-1)) between the two copper(II) centers.