Abstract

SOUZA, Elizeu J. de et al. Novel zwitterionic oxorhenium(V) complexes: synthesis, characterization and crystal structure of [ReOX₂(Hdhp)(PPh₃)] (X = Cl, Br; H₂dhp = 2,3-dihydroxypyridine). J. Braz. Chem. Soc. [online]. 2006, vol.17, n.8, pp. 1578-1583. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532006000800014.

Two novel zwitterionic oxorhenium(V) complexes, [ReOCl₂(Hdhp)(PPh₃)] (1) and [ReOBr₂(Hdhp)(PPh₃)] (2) (H₂dhp = 2,3-dihydroxypyridine), were synthesized and characterized by infrared spectroscopy, ¹H and ³¹P nuclear magnetic resonance, elemental analysis and crystal and molecular structure determination by X-ray diffraction on single crystals. Both complexes show distorted octahedral coordination geometry, with the halide ligands arranged in equatorial cis positions, the triphenylphosphine ligand in a trans position to one of the halides and the Hdhp^- ligand coordinated in a bidentate form through its oxygen atoms, one in trans position to the oxo-ligand and the other in trans position to the second halide. The nitrogen atom of this ligand is protonated. Compounds 1 and 2 show quite different crystal packing, both influenced by hydrogen bonds of the types N-H...X (X = Cl, Br) and N-H...O.

Keywords : oxorhenium(V); zwitterionic complexes; 2,3-dihydroxypyridine.