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

Magnetic, spectral, and thermal behaviour of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II)

W. Ferenc, B. Cristóvão, B. Mazurek, and J. Sarzyński

Faculty of Chemistry, Maria Curie-Skłodowska University, PL-20-031 Lublin, Poland

E-mail: Wieslawa.Ferenc@umcs.lublin.pl

Received: 10 October 2005  Revised: 2 March 2006  Accepted: 13 March 2006

Abstract: Some physicochemical properties of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono-and dihydrates with a metal ion—ligand mole ratio of 1: 2. All complexes are polycrystalline compounds. Their colours depend on the kind of central ion: pink for Co(II) complex, green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293 K–523 K because it was found that on heating in air above 523 K 2-chloro-4-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step. During dehydration process no transformation of the nitro group to nitrito one took place. Their solubilities in water at 293 K are of the orders of 10⁻³-10⁻² mol dm⁻³. The magnetic moment values of 2-chloro-4-nitrobenzoates determined in the range of 76 K–303 K change from 3.48µ_B to 3.82µ_B for Co(II) complex, from 2.24µ_B to 2.83µ_B for Ni(II) 2-chloro-4-nitrobenzoate, and from 0.31µ_B to 1.41µ_B for Cu(II) complex. 2-Chloro-4-nitrobenzoates of Co(II) and Ni(II) follow the Curie—Weiss law, but the complex of Cu(II) forms dimer.

Keywords: complexes - metals - benzoate derivatives

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-006-0037-5

Chemical Papers 60 (3) 207–213 (2006)