Reaction of the Biheteroaromatic Ligand 2-(2'-Pyridyl)Quinoxaline (L) with Zinc(Ii) and Cadmium(Ii) Halides - Preparation and Characterization of the 1/1 Complexes

 
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1995 (EN)
Reaction of the Biheteroaromatic Ligand 2-(2'-Pyridyl)Quinoxaline (L) with Zinc(Ii) and Cadmium(Ii) Halides - Preparation and Characterization of the 1/1 Complexes (EN)

Perlepes, S. P. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Perlepes, S. P. (EN)

The reactions of ZnX(2) and CdX(2) (X = Cl, Br, I) with the biheteroaromatic ligand 2-(2'-pyridyl)quinoxaline (L) were studied in ethanolic solutions. The new complexes [ZnX(2)L] (X = Cl, Br, I), [CdI(2)L] and [Cd(2)X(4)L(2)] were isolated and characterized by elemental analyses, conductivity measurements, X-ray powder patterns, thermal methods (TG/DTG, DTA) and spectroscopic (IR, far-IR, Raman, H-1 NMR) studies. The X-ray crystal structure of [ZnCl(2)L] . 0.5MeOH shows a distorted tetrahedral geometry around the zinc(II) atom. The ligand L acts as a bidentate chelate with the ligated atoms being the pyridine nitrogen and one of the quinoxaline nitrogens. A monomeric pseudo-tetrahedral structure is also assigned for [ZnBr2] and [MI(2)L] (M = Zn, Cd). Dimeric structures are proposed for the chloro and bromo cadmium(II) compounds, in which the two metal centres are bridged by two halo ligands, with a terminal halide and a chelating molecule of L completing five-coordination at each metal. All data are discussed in terms of the nature of bonding and known and assigned structures. A complex with the empirical formula Cd(2)Cl(4)L was isolated during the thermal decomposition of [Cd(2)Cl(4)L(2)]; the vibrational study of this thermally stable intermediate shows that L acts as a tridentate bridging ligand. The crystal structure of [Hg(2)Br(4)L(2)], which was not available when the results of the HgX(2)/L chemistry had been published, is also described. (EN)

crystal-structure (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Polyhedron (EN)

English

1995

<Go to ISI>://A1995RB57400009

Elsevier (EN)



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