DINUCLEAR ZINC(II) COMPLEXES OF A ROBSON MACROCYCLE

Dinuclear zinc(II) complexes of the Robson macrocycle H(2)L, derived f rom the cyclocondensation of 2,6-diformyl-4-methylphenol and propane-1 ,3-diamine have been synthesised and their crystal structures determin ed. The compound Zn-2(L)(ClO4)(2).2H(2)O crystallises in the monoclini c space group P2(1)/a (C-2h(5) no. 14) with a = 14.755(15), b = 12.348 (12), c = 16.825(17) Angstrom, beta = 105.80(3)degrees and Z = 4. The crystal structure consists of two independent pairs of dinuclear zinc complexes (molecules 1 and 2). Molecule 1 contains two six-co-ordinate zinc(II) with an intermetallic distance of 3.166 Angstrom, and molecu le 2 has two five-co-ordinate zinc(II) with a Zn...Zn distance of 3.17 7 Angstrom. The compound [Zn-2(L)(N-3)(2)] crystallises in the monocli nic space group P2(1)/c (C-2h(5), no 14) with a = 7.733(5), b = 11.865 (6), c = 14.466(4) Angstrom, beta = 90.86(4)degrees and Z = 2. The two zinc atoms are five-co-ordinate and are separated by 3.333 Angstrom.