ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Preparation, Spectral and Thermal Properties of Two Tetracyanopalladates(II) of Nickel(II) and the Crystal Structure of [Ni(en)₃][Pd(CN)₄] ] H₂O

J. Bubanec, J. Černák, I. Potočňák, M. Drábik, and J. Lipkowski

Institute of Chemistry, P. J. Šafárik University, SK-041 54 Košice

E-mail: cernakju@kosice.upjs.sk

Received: 17 December 2002  Accepted: 3 March 2004

Abstract: From the aqueous system Ni²⁺-en-[Pd(CN)₄]²⁻ (en is 1,2-diaminoethane) the complexes [Ni(en)₃][Pd(CN)₄] ·H₂O and Ni(en)₂Pd(CN)₄ · 2H₂O were prepared and characterized. The structure of the first one was solved using single crystal X-ray analysis; it is ionic and is formed of [Ni(en)₃]²⁺cations, [Pd(CN)₄]²⁻ anions, and water molecules of crystallization. The hydrogen bonds of the O—H· · ·N, N—H· · ·O, and N—H· · ·N type contribute to the stabilization of the structure. The thermal decomposition reactions of both compounds were studied in the air atmosphere under dynamic conditions. The decompositions of both compounds begin with dehydration and are followed by stepwise formation of intermediate(s) with lower en contents. In the case of the second complex a phase transition concerning Ni(en)₂Pd(CN)₄ is observed at 140°C. The final products are oxides PdO and NiO.

Chemical Papers 58 (4) 224–231 (2004)