Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes of 2-nitrobenzoic acid with methyl carbazate as ancillary ligand. Crystal structure of the copper(II) complex

Divalent metal complexes of general formula M(2-nb)(2)(mc)(2)].2(2-nbH), where M = Co(II), Ni(II), Cu(II) or Zn(II), 2-nbH = 2-nitrobenzoic acid and mc = methyl carbazate (NH2NHCOOCH3), have been prepared and characterized by physicochemical and spectroscopic methods. Single-crystal X-ray study of the Cu(II) complex revealed that the molecule is centrosymmetric, with two N,O-chelating mc ligands in equatorial positions and a pair of monodentate 2-nb anions in the axial positions. The lattice 2-nbH molecules help to establish the packing of monomers through hydrogen-bonding interactions. Thermal stability and reactivity of the complexes were studied by TG-DTA. Emission studies show that these complexes are fluorescent

A family of double-layered coordination polymers containing Cd²⁺, N,O-chelating ligands, and bridging SCN⁻ and Cl⁻

<div><p>The syntheses, structures, and characterization (IR, TGA/DTA) of a family of layered coordination polymers containing Cd²⁺, bridging anions (SCN⁻ and Cl⁻), and chelating C₂H₆N₂O₂ methyl carbazate (mc) and C₃H₈N₂O₂ ethyl carbazate (ec) ligands are described, viz: Cd(SCN)₂(C₂H₆N₂O₂), Cd(SCN)Cl(C₂H₆N₂O₂), Cd(SCN)₂(C₃H₈N₂O₂), and Cd(SCN)Cl(C₃H₈N₂O₂). Single-crystal structures show them to contain distorted CdN₃OS₂ (for the thiocyanate) and CdN₂OCl₂S (for the thiocyanate/chloride) octahedra, in which the mc and ec ligands adopt an N,O-bidentate coordination mode, and the four anions bridge adjacent metal ions, which leads to polymeric sheets built up from double-octahedral layers propagating in the (1 0 0) plane. The topological linkage of the metal ions, which is the same in each structure, can be described as a distorted hexagonal grid. The crystal structures are completed by weak N–H⋯O, N–H⋯N, N–H⋯Cl, and N–H⋯S hydrogen bonds, which all occur within the (1 0 0) polyhedral layers.</p></div