| Autor: |
Psaroudakis, Nikos, Terzis, Aris, P. Raptopoulou, Catherine, Mertis, Constantinos |
| Zdroj: |
Journal of the Chemical Society, Dalton Transactions; January 1997, Vol. 1997 Issue: 18 p3299-3304, 6p |
| Abstrakt: |
The triangulo Re39+ cluster [Re3(-Cl)3X9]3- (X = Cl 1a or Br 1b) in concentrated aqueous hydrohalogenic acid solutions underwent a facile one-electron reduction by various reducing agents (VCl2·4H2O, Sn–SnCl2 or Hg) to give the air-sensitive Re38+ anion [Re3(-Cl)3X9-n (H2O)n](4-n) - (X = Cl 2a or Br 2b), where n may be 1; the diamagnetism and EPR silence of this compound indicate that it may exist as a dimer with a direct or indirect rhenium–rhenium bond linking two Re38+ trimetal cores. Oxidation of 2 by molecular oxygen in 6 mol dm-3 HX (X = Cl or Br) solutions yielded 1 quantitatively, whereas in the absence of acid and in aprotic solvents oxo-derivatives are formed; from 2b the hexanuclear anion [{Re3(-Cl)3Br6(H 2O)(-O)}2]2- 3b was obtained whose structural characterization, as its [PPh4]+ salt 3c, shows that two -O ligands bridge two oxidized Re310+ units. The structure of the Re39+ cluster [Co(en)3][Re3(-Cl)3Br 8(H2O)]Br has been also determined by X-ray diffraction. The redox couple xRe39+–(Re38 )x, where x = 1 or 2, derived upon mixing 6 mol dm-3 HX (X = Cl or Br) solutions of 1 with an excess of mercury, catalyses efficiently the reduction of molecular oxygen to water. |
| Databáze: |
Supplemental Index |
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