Synthesis and crystal structures of the first cobalt complexes of macrocyclic oxamido

One novel macrocyclic oxamido-cobalt (II) complex CoL (H2L = 2,3-dioxo-5,6;13,14-dibenzo-7,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-7,11-diene) (1) has been synthesized solvothermally and characterized by X-ray diffraction analysis. By using the mononuclear cobalt complex as a building block and N3− as auxiliary groups, a trinuclear complex (CoL)2Mn(N3)4·2H2O (2) and two one-dimensional complexes (CoL)2Cd(N3)4·2H2O (3), (CoL)2Co(N3)4·2H2O (4) have been prepared by stepwise synthesis and characterized. The structure of complex 1 consists of a neutral cobalt (II) complex of the [14] N4 macrocyclic oxamido dianion. In complex 2, the center manganese (II) ion is in a slightly distorted octahedral environment and N3− groups only act as terminal ligands. Complex 3 and 4 are similar in structure and both show a one-dimensional chain structure via oxamido and N3− ligands. N3− ligands show two kinds of coordination mode. In complex 2–4, cobalt ion in the ring is trivalence.