Syntheses and X-ray crystal structures of [Zn(cyclen)–im–Zn(cyclen)](ClO4)3 and [Ni(cyclen)(imH)(ClO4)](ClO4) (cyclen=1,4,7,10-tetraazacyclododecane, im=imidazolate)

The imidazolate-bridged binuclear zinc(II) macrocyclic complex, [Zn(cyclen)–im–Zn(cyclen)](ClO4)3 (1) and the free imidazole coordinated mononuclear nickel(II) complex, [Ni(cyclen)(imH)(ClO4)](ClO4) (2) (cyclen=1,4,7,10-tetraazacyclododecane, im=imidazolate) have been synthesized. Complexes 1 and 2 have been characterized by single crystal structural analyses. In complex 1 both zinc(II) ions are five-coordinated with a distorted square pyramidal geometry composed of four nitrogen atoms from cyclen and one nitrogen atom from the bridging imidazolate ion with N5 chromophore. Complex 2 is mononuclear nickel(II) having six-coordination with distorted octahedral geometry consisting of four nitrogen atoms from cyclen, one nitrogen atom from the imidazole molecule and one oxygen from one of the perchlorate ions to give a N5O chromophore.