Thermal properties of the molybdenum - oxide based {Mo₁₅₄} giant wheel type cluster with methanol ligands bonded to its surface

• Autorzy: Bielański, A. , Małecka-Lubańska, A. , Krickemeyer, E. , Bögge, H. , Schmidtmann, M. , Müller, A.
• Języki publikacji: EN

Abstrakty

EN

The thermal behaviour of the giant molybdenum ring cluster compound formula - containing H2O ligands partly substituted by methanol molecules - was studied using TG, DTG and DTA analyses simultaneously, and mass spectromet-ric analysis of the decomposition products. Methanol is released from the sample quite rapidly even at room temperature (and even before the experiments start) but small traces of methanol are still present which we tried to use for characterising the different stages of giant ring transformation. The initial rapid loss of mass of the sample was accompanied by the DTA and DTG peak at 75°C. A small DTA endothermic peak at 165°C was assigned to an MS maximum indicating the increased emission of methanol and formaldehyde. Double exothermic peaks at 352 and 366° C corresponded to the loss of water formed from the abundant OH groups. Simultaneously, peaks indicating trace emission of formaldehyde, methanol, carbon dioxide as well as traces of hydrocarbons containing 2-4 carbon atoms per molecule were registered mass spectrometrically. The exothermic effect was attributed to a kind of "recrystallisation" process of the completely dehydrated product.

Słowa kluczowe

PL

klaster; stabilność cieplna

EN

nanosized clusters; polyoxometalates; thermal stability; supramolecular chemistry

• Czasopismo: Bulletin of the Polish Academy of Sciences. Chemistry
• Rocznik: 2001
• Tom: Vol. 49, No. 3
• Strony: 245-254
• Opis fizyczny: Bibliogr. 8 poz.

Twórcy

autor

Bielański, A.

autor

Małecka-Lubańska, A.

autor

Krickemeyer, E.

autor

Bögge, H.

autor

Schmidtmann, M.

autor

Müller, A.

• Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 7, 30-239 Kraków, Poland (Instytut Katalizy i Fizykochemii Powierzchni PAN)