Formation, structural characterization, and thermal decomposition of the adducts X(3)Ga center dot P(SiMe(3))(3) (X=Cl, Br, I)

The adducts X(3)Ga . P(SiMe(3))(3) [X = Cl (1), Pr (2), I (3)] were prepared in high yields from the combination of the respective gallium trihalides with P(SiMe(3))(3) in hydrocarbon solvents at ambient temperature. The adducts were characterized by NMR, MS, elemental analysis, and single-crystal X-ray structure determinations. Particularly, the H-1 NMR study of 1-3 helped to correct our previously published results regarding monomer-dimer equilibria of the related [X(2)GaP(SiMe(3))(2)](2) in solution. The crystal structure determinations showed that 1 and 2 were solvated, 1 . C6H5Cl and 2 . C7H8, respectively, and that 3 was solvent-free. The thermal decomposition of 1-3 was studied by TGA along with a determination of the volatiles from pyrolysis and analysis of the final solid product. The pyrolyses of 1-3 at 450 degrees C under vacuum resulted mainly in nanocrystalline GaP with 4-5 nm-particle average sizes as determined by X-ray powder diffraction (XRD) and, for pyrolysis of 2, by transmission electron microscopy (TEM); in addition, small quantities of amorphous Si/C/H containing phases were also formed.