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New Pnictinogallanes H2GaE(SiMe3)23 (E = P, As) - Formation, Structural Characterization, and Thermal Decomposition to Afford Nanocrystalline GaP and GaAs
DUKE UNIV DURHAM NC DEPT OF CHEMISTRY
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The new compounds, H2GaESiMe323, E P 1, As 2, the first authenticated examples of a phosphinogallane and an arsinogallane, containing the GaH2 moiety, are prepared via efficient dehydrosilylation from the respective combinations of H3Ga.NMe3 and ESiMe33 in diethyl ether or toluene. Compounds 1 and 2 are characterized by elemental analysis, NMR, IR, and mass spectrometry. Single-crystal X-ray structural studies show that the molecular structures of 1 and 2 feature a flattened six-member ring of alternating Ga and E centers. Both compounds are reasonably stable at -30 deg C but spontaneously decompose at ambient temperatures, 2 noticeably faster than 1, with the evolution of HSiMe3, H2, and ESiMe33. The pyrolysis of 1 yields nanocrystalline GaP while the pyrolysis of solids from decayed 2 results in nanocrystalline GaAs as determined from XRD studies. Under applied pyrolysis conditions, the thermally accelerated dehydrosilylation of the precursors is accompanied by a side-evolution of CH4 and retention of small quantities of amorphous SiC phases.
APPROVED FOR PUBLIC RELEASE