Nickel(II), Copper(I) and Copper(II) Complexes of Bidentate Heterocyclic Thiosemicarbazones

Journal of the Brazilian Chemical Society

Beraldo, Heloisa¹  Carneiro, Tania M. Gomes¹  Teixeira, Letícia Regina de Souza¹  Lima, Rejane Lúcia de¹  Universidade Federal de MinasUniversidade Federal de Minas, Belo Horizonte, Brazil¹ 

关键词: heterocyclic thiosemicarbazones;    bidentate thiosemicarbazones;    nickel(II);    copper(I);    copper(II);   

DOI  :  10.1590/S0103-50531999000300005

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

Thiosemicarbazones and their metal complexes are a broad class of biologically active compounds1. Metal complexes of N-heterocyclic thiosemicarbazones derived from 2-formylpyridine (H2FPT) and 2-acetylpyridine (H2APT) were extensively described in the literature2, but very few works deal with those derived from 3- and 4-formylpyridine (H3FPT, H4FPT, Fig. 1) and 3- and 4-acetylpyridine (H3APT, H4APT, Fig. 1). In some cases, lowering of the thiosemicarbazone’s denticity leads to a decrease of activity2 but the literature reports examples of biologically significant bidentate thiosemicarbazones. The compound p-acetamidobenzaldehyde thiosemicarbazone, for example, known as thioacetazone, is employed in the clinical treatment of tuberculosis3 and functions as a potential N-S bidentate ligand. In previous works we studied the iron(II), iron(III), copper(II) and zinc(II) complexes of H2FPT and H2APT4-7. In the present article we report the syntheses and characterization of complexes of H3FPT, H4FPT, H3APT and H4APT with nickel(II), and copper(I) or copper(II).   Experimental IR spectra were recorded by means of a Perkin Elmer 283B spectrometer using Nujol mulls between CsI plates and NMR spectra with a Brucker DRX-400 Avance (400 MHz) spectrometer. The thermogravimetric data were obtained in dynamic air atmosphere at 10 °C/min in the 25 - 750 °C range, by using a Mettler TA 4000 TG50 analyzer. A YSI model 31 conductivity bridge was employed for molar conductivity measurements. The magnetic susceptibilities of the solids were measured at room temperature with a Johnson Matthey Magnetic Susceptibility balance. Partial elemental analyses were performed using a Perkin Elmer 240 equipment. H3FPT, H4FPT, H3APT and H4APT were obtained by refluxing an ethanolic solution of 3- or 4-formylpyridine and 3- or 4-acetylpyridine with thiosemicarbazide (all purchased from Aldrich Chemical Company and used without purification) as described in the literature8. The complexes were prepared by refluxing ethanolic solutions of the thiosemicarbazone and the metal(II) perchlorate in molar ratio M:L 1:2 during 5-6 h. In the

【 授权许可】

Unknown