Divalent metal complexes of formylhydrazine: Syntheses and crystal structures of M(CH4N2O)2(H2O)2·2NO3 (M = Zn, Co)

The syntheses and crystal structures of Zn(CH4N2O)2(H2O)2·2(NO3) (1) and Co(CH4N2O)2(H2O)2·2(NO3) (2), the first well-characterised metal complexes of formylhydrazine (fh), are described. In both compounds, the fh acts as an N,O-bidentate ligand in a centrosymmetric [M(fh)2(H2O)2]2+ cation, with charge balance supplied by nitrate counter ions. The packing for the two compounds are quite different: in 1, chains of [Zn(fh)2(H2O)2]2+ units are seen in the triclinic unit cell, whereas in the monoclinic structure of 2, sheets of cations occur. This might arise because the conformations of the five-membered chelate rings for the ligands are slightly different, with that for 2 showing a greater degree of puckering.