Naslov
Alkoxides of the Hexanuclear Cluster Units [M_6X_12]^n+ (M = Nb or Ta, X = Cl or Br, n = 2, 3 or 4) and [Mo_6X_8]^4+

Autori
Brničević, Nevenka ; Muštović, Faiza ; Hoxa, Besnik

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts, XXIV International Conference on Coordination Chemistry / Konstantatos, A. ; Mertis, K. ; Panayotou, M. ; Papavissiliou, G. ; Pnevmatikakis, G. ; Tsatsas, A. Vrachou-Astra, E. - Atena : Association of Greek Chemists, 1986, A2-134

Skup
XXIV International Conference on Coordination Chemistry

Mjesto i datum
Atena, Grčka, 24.08.1986. - 29.08.1986

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
hexanuclear cluster units; alkoxides; diamagnetic

Sažetak
The hexanuclear cluster units [M_6X^i_12]X^a_2x8H_2O with M=Nb, or Ta, X=Cl or Br, i=inside, a=outside, react with alkali metal alkoxides in methanol as solvent by the exchange of the two terminal (X^a) halogens with methoxide groups. The crystalline, diamagnetic cluster methoxides [M_6X_12](OCH_3)_2x4CH_3OH are formed, which according to the X-ray diffraction patterns could not be clasified in any of the five structural groups found within [M_6X_12]^2+ cluster units. In an alkaline medium (OCH_3^-/[M_6X_12]^2+ greater-than or equal to 6) the air-oxygen oxidation of [Ta_6Cl_12]^2+ is found and series of 4+ cluster methoxides M'_2[Ta_6Cl_12](OCH_3)_6x6CH_3OH, M'=Li, Na, K, Rb, is isolated. Due to the thermal and chemical stability of the [Ta_6Cl_12]^n+ in alcohol and aqeous solutions this units could serve as a powerful oxidizing-reducing agents for the reversible multielectron photochemical recations through the vide range of pH values. an irreversible deprotonation of methanol molecules is found as a result of the reaction with [Mo_6X^i_12]X^a_4, X=Cl or Br. The reaction involves two alkoxide groups for the two of the four outside(X^a) halogen atoms exchange with a formation of the solid cluster alkoxides [Mo_6X_8]X_2(OCH_3)_2x2CH_3OH and halogen acids. The spectral evidences indicate the bridging intermolecular methoxide groups. Deprotonation of alyphatic alcohol molecules in the presence of the hexanuclear (M_6) cluster units and the exothermal exchange of the OCH^-_3 groups for the inside (X^i) halogen atoms are considered.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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