Original scientific paper

Synthesis, Characterization and Thermal Decomposition of [Cu(H₂O)₂(nia)₂S0₄], nia = Nicotinamide

Bojan Kozlevčar ; University of Ljubljana, Ljubljana, Slovenia, Faculty of Chemistry and Chemical Technology
Barbara Novosel ; University of Ljubljana, Ljubljana, Slovenia, Faculty of Chemistry and Chemical Technology
Marko Petrić ; University of Ljubljana, Ljubljana, Slovenia, Department of Wood Science and Technology
Marjeta Sentjurc ; University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute
Primož Šegedin ; University of Ljubljana, Ljubljana, Slovenia, Faculty of Chemistry and Chemical Technology

Abstract

[Cu(H20)2(nia)2S04], nia = nicotinamide, was prepared by the reaction between aqueous solutions of CuS04 • 5H20 and nicotinamide, and was characterized by standard chemical and physical methods. Thermal behaviour of the sample in inert atmosphere proceeds in several steps. The dehydration of the sample (330—445 K) with 8.3% of mass loss (theoretical value 8.2%) is followed by a strong exothermal peak in DTA curve at 462 K, which is not accompanied by any significant mass change. Changes in electronic spectra and powder patterns of residues indicate a recrystallization process.
This suggestion was confirmed by the EPR spectra of powder samples recorded in the temperature range from 295 K to 473 K. Changes of g values reflect modifications of the coordination sphere around copper(II) in the temperature range from 295 K to 423 K.
In this temperature range, the symmetry type of the complex should have remained the same. However, above 423 K EPR spectra reflect major structural alternations. Significant changes of IR spectra in 900-1250 cm-1 region, where characteristic bands of S042- are present, indicate changes in the coordination mode of sulfate anion. All the observed results can be interpreted by slightly modified anation reaction in the solid state
[Cu(H20)2(nia)2S04](s)—^->[Cu(nia)2S04](s) + 2 H20(g) 

Keywords

Hrčak ID:

135655

URI

https://hrcak.srce.hr/135655

Publication date:

3.11.1997.

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