New copper(II) complexes with hydroxypyridines: Synthesis, structural, thermal, and magnetic properties

We have synthesized and characterized four new copper(II) complexes with 2-hydroxypyridine in its lactam tautomeric form (2-pydo) and 4-hydroxypyridine in both lactim (4-hpy) and lactam (2-pydo) tautomeric forms: [Cu-2(mu-Ac)(4)(4-pydo)(2)]center dot 2CH(3)CH (1), [Cu(Ac)(2)(4-hpy)(2)(H2O)] (2), [Cu(2-pydo)(4)(NO3)(2)] (3), and [Cu(4-pydo)(2)(NO3)(H2O)(2)]NO3 (4). The products were characterized structurally by single-crystal X-ray analysis and FT-IR spectroscopy. The complexes consist of five or six coordinated central Cu2+ ion with 4-pydo, 4-hpy, 2-pydo, acetate, nitrate, and water ligands. Magnetic measurements carried out between 2 and 300 K give the results of mu(eff) approximate to 1.7 BM at room temperature, as expected for Cu2+. The thermal analysis showed that the final product, obtained by heating the title compounds to 600 degrees C in nitrogen, is nanosized elemental copper. The results are comparable to those reported in literature for analogous compounds.