SYNTHESIS AND COORDINATION CHEMISTRY OF 1,5,9-TRIAZACYCLODODECANE MONOSUBSTITUTED WITH IMIDAZOLE AND PYRAZOLE

The potentially tetradentate ligands 1-(imidazol-4-ylmethyl)- (L(1)), 1-(1-methylimidazol-2-ylmethyl)- (L(2)) and 1-(pyrazol-3-ylmethyl)-1,5 ,9-triazacyclododecane (L(3)) have been synthesized; L(1) was isolated as the tetrahydrochloride, L(1) . 4HCl. The basicity constants of L(1 ) and L(3) have been determined by potentiometry at 25 degrees C in Na Cl. The co-ordination chemistry of L(1) and L(3) toward some 3d metal ions has been investigated and the complexes [ML(3)(Cl)]Y (M = Mn or F e, Y = BPh(4); M = Ni, Y = BF4) and [ML(ClO4)]BPh(4) (M = Co, L = L(3) ; M = Cu or Zn, L = L(1) or L(3)) have been isolated and-characterized . The structures:of the iron(II) and nickel(II) complexes of L(3) have been determined by single-crystal X-ray analyses. Both contain dimeri c [{ML(3)(Cl)}(2)](2+) complex cations in which each metal ion is six- co-cordinated by four nitrogen donors of one L(3) ligand and by two br idging Cl- ions in an approximately octahedral environment.