Crystal structure and thermal properties of bis-[μ-2-(meth-oxy-carbonyl-hydrazinyl-idene)acetato-κ ,:]bis-[di-aqua-(thio-cyanato-κ)manganese(II)] tetra-hydrate.

The title compound, [Mn(CHNO)(NCS)(HO)]·4HO (I), exists as a centrosymmetric dimer. Each dimeric unit consists of tridentate (,,)-chelating Schiff bases with symmetry-maintained μ--bridged carboxyl-ate anions, terminally bound thio-cyanate anions, and ligated and solvated water mol-ecules. The complex exhibits a distorted octa-hedron geometry and the centrosymmetric μ--bridged carboxyl-ate anions connect the two manganese atoms to form an O ring.

Cationic, neutral and anionic metal(II) complexes derived from 4-oxo-4H-pyran-2,6-dicarboxylic acid (chelidonic acid).

The structures of five metal complexes containing the 4-oxo-4H-pyran-2,6-dicarboxylate dianion illustrate the remarkable coordinating versatility of this ligand and the great structural diversity of its complexes. In tetraaquaberyllium 4-oxo-4H-pyran-2,6-dicarboxylate, [Be(H(2)O)(4)](C(7)H(2)O(6)), (I), the ions are linked by eight independent O-H..

Tris(ethyl carbazate-κN,O)nickel(II) dinitrate.

The asymmetric unit of the title compound, [Ni(C(3)H(8)N(2)O(2))(3)](NO(3))(2), contains two independent cations, each built up around a fac-NiN(3)O(3) octa-hedron, and four nitrate anions. Numerous cation-to-anion N-H⋯O hydrogen bonds, some of which are bifurcated, help to establish the packing.