Saturday, July 29, 2006

Chemistry - A European Journal, Volume: 12, Issue: 20 , pp. 5282 - 5292

Solid-State NMR and EXAFS Spectroscopic Characterization of Polycrystalline Copper(I) O,O’-Dialkyldithiophosphate Cluster Compounds: Formation of Copper(I) O,O’-Diisobutyldithiophosphate Compounds on the Surface of Synthetic Chalcocite I) Rusanova, Daniela; Pike, Kevin J.; Persson, Ingmar; Hanna, John V.; Dupree, Ray; Forsling,

Abstract: A number of polycrystalline copper(i) O,O’-dialkyldithiophosphate cluster compounds with Cu4, Cu6, and Cu8 cores were synthesized and characterized by using extended X-ray absorption fine-structure (EXAFS) spectroscopy.The structural relationship of these compounds is discussed. The polyACHTUNGTRENUNGcrystalline copper(i) O,O’-diisobutyl ACHTUNG- TRENUNGdithiophosphate cluster compounds,[Cu8ACHTUNGTRENUN {S2PACHTUNG- TRENUNG(OiBu)2}6(S)]and [Cu6ACHTUNGTRENUNG{S2PACHTUNGTRENUNG(OiBu)2}6], were also characterized by using 31P CP/MAS NMR CP = cross polarization, MAS =magic-angle spinning) and static 65Cu NMR spectroscopies (at different magnetic fields) and powder X-ray diffraction (XRD) analysis. Comparative analyses of the 31P chemical-shifttensor, and the 65Cu chemical shift and quadrupolar-splitting parameters, estimated from the experimental NMR
spectra of the polycrystalline copper(i) cluster compounds, are presented. The adsorption mechanism of the potassium O,O’-diACHTUNGTRENUNGisobutyldithiophosphate collector, KACHTUNGTRENUNG[S2PACHTUNGTRENUNG(OiBu)2], at the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy and scanning electron microscopy (SEM). 31P NMR resonance lines from collector-treated chalcocite surfaces were assigned to a mixture of [Cu8ACHTUNGTRENUNG {S2PACHTUNGTRENUNG (OiBu)2}- 6(S)]and [Cu6- ACHTUNGTRENUNG{S2PACHTUNGTRENUNG(OiBu)2}6]compounds .

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