A new coordination mode of pyrazine-2,3-dicarboxylic acid and its first monodentate complexes: Syntheses, spectral, thermal and structural characterization of [Cu(pzdca)(H2O)(en)2] · H2O and [Cu(pzdca)(H2O)(dmpen)2]

The novel aquabis(ethylenediamine)pyrazine-2,3-dicarboxylatocopper(II) hydrate, [Cu(pzdca)(H2O)(en)2] · H2O (1) and aquabis(2,2-dimethylpropane-1,3-diamine)pyrazine-2,3-dicarboxylatocopper(II) complex, [Cu(pzdca)(H2O)(dmpen)2] (2), (H2pzdca = pyrazine-2,3-dicarboxylic acid, en = ethylenediamine and dmpen = 2,2-dimethylpropane-1,3-diamine), with a new coordination mode of pyrazine-2,3-dicarboxylic acid, have been prepared and characterized by elemental analyses, IR spectroscopy, thermal analyses and single crystal X-ray diffraction. Both complexes crystallize in the triclinic system, space group P1¯ and in which the Cu(II) ions exhibit a distorted octahedral coordination by a monodentate pzdca dianion, two bidentate en or dmpen ligands and one aqua ligand. The thermal decomposition of the complexes has been predicted with the help of thermal analyses (TG, DTG and DTA).

In the [Cu(pzdca)(H2O)(en)2]·H2O and [Cu(pzdc)(H2O)(dmpen)2] complexes, the pyrazine-2,3-dicarboxylate ligand exhibits new coordination mode and these complexes are the first example of the pzdca ligand exhibiting monodentate coordinated to the metal ions.Figure optionsDownload as PowerPoint slide