SYNTHESIS AND COORDINATING PROPERTIES OF THE FUNCTIONALIZED MACROCYCLIC LIGAND -YLMETHYL)-7-CARBOXYMETHYL-1,4,7-TRIAZACYCLONONANE - CRYSTAL-STRUCTURES OF COBALT(III), NICKEL(II) AND ZINC(II) COMPLEXES

The synthesis of the new unsymmetrically derivatized macrocycle -ylmet hyl)-7-carboxymethyl-1,4,7-triazacyclononane (LH) is reported. The pot entially hexadentate ligand yields cobalt(III), nickel(II) and zinc(II ) complexes of formulae [CoL](PF6)(2) (1), [NiL]PF6 . CH3OH (2) and [Z nL]ClO4 . H2O (3), which have been isolated in the solid state and cha racterized. The nickel complex is remarkably stable towards ligand dis sociation in water solution even in the presence of a large excess of CN-. The structures of the complexes have been determined by single-cr ystal X-ray analyses. Compound 1 crystallizes in the triclinic space g roup P (1) over bar, a =7.397(2), b = 10.960(4), c = 17.420(5) Angstro m, alpha = 101.51(3), beta = 91.85(4), gamma = 98.24(3)degrees, Z = 2. Compound 2 is monoclinic P2(1)/a, a = 14.094(15), b = 11.045(4), c = 16.905(5) Angstrom, beta = 105.54(7)degrees, Z = 4; 3 is triclinic P ( 1) over bar, a = 7.903(4), b = 9.218(5), c = 16.996(10) Angstrom, alph a = 98.51(6), beta = 96.76(8), gamma = 101.98(7)degrees, Z = 2. In eac h complex cation the metal atom is six-coordinated, being surrounded b y the three macrocycle nitrogens, the two imidazole nitrogens and one carboxylate oxygen atom, with a coordination geometry which is approxi mately trigonal antiprismatic in 1 and 2 and trigonal prismatic in 3. (C) 1998 Elsevier Science S.A. All rights reserved.