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RESEARCH PRODUCT

New Route to Polynuclear Ni(II) and Cu(II) Complexes with Bridging Oxime Groups That Are Inaccessible by Conventional Preparations

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A series of new polynuclear complexes of divalent Ni and Cu with 2-cyano-2-oximino-acetic acid (later AACO2-) were obtained as the result of the ligand modification reaction in the process of complexation, using 2-cyano-2-oximino-acetates such as methyl- (later as MeCO), and ethyl- (as ECO later on). Synthesized compounds were characterized by spectroscopic methods, thermal analysis, magnetochemistry, and X-ray crystallography. Crystal data revealed the formation of the dimeric [Ni(AACO)(H2O)3]2·H2O (1), trimeric K2[Ni3(AACO)4(H2O)4]·4H2O (2), and K2[Cu3(AACO)4(H2O)4]·4H2O (3) complexes, with bridging NO-groups cyanoxime dianions. In the latter two compounds, the AACO2– anions adopt cis-arrangements around metal centers. One mononuclear complex of K2[Cu(AACO)2(H2O)]·2H2O (4) composition was isolated and characterized as well, where the cyanoxime forms the trans-complex 4. There is moderate-to-strong antiferromagnetic coupling between metal centers in polynuclear complexes. Data of thermal analysis studies...