SYNTHESIS AND CHARACTERIZATION OF NOVEL ORGANOGALLIUM PHOSPHORUS-COMPOUNDS - X-RAY CRYSTAL-STRUCTURES OF PH2GAP(SIME3)2GA(PH)2CL, PH2(CL)GA.P(SIME3)3, AND PH3GA.P(SIME3)3

A Ga-P-Ga-Cl ring containing compound, Ph2GaP(SiMe3)2Ga(Ph)2Cl (1), is reported. Compound 1 is an example of a four-membered ring system with mixed bridging of the two gallium centers and was prepared via the reaction of Ph2GaCl with P(SiMe3)3 in a 2:1 mole ratio in either toluene or pentane. Curiously, 1 was originally isolated as a minor product (ca. 5% yield) from the reaction of LiP(SiMe3)2 with Ph2GaCl in a 1:1 mole ratio. X-ray crystallographic analyses shows the Ga-P-Ga-Cl ring of 1 to be nonplanar. The reaction of Ph2GaCl and P(SiMe3)3 in a 1:1 mole ratio in either toluene or pentane yields Ph2(Cl)Ga.P(SiMe3)3 (2). Compound 3, Ph3Ga.P(SiMe3)3, was also originally isolated as a minor product (ca. 10%) from the reaction of LiP(SiMe3)2 with Ph2GaCl in a 1:1 mole ratio and is an additional reported example of an adduct formed through ligand redistribution involving LaE(SiMe3)2 (E = P or As) as a reactant. The straightforward synthesis of 3 can be accomplished by the 1:1 mole reaction of Ph3Ga and P(SiMe3)3 in pentane. Both 2 and 3 are structural examples of adducts containing a Ga-P bond with aryl ligands on the gallium center. Compound 1 belongs to the monoclinic system, space group P2(1)/c, with z = 4, a = 10.579 (2) angstrom, b = 15.653 (5) angstrom, c = 20.428 (4) angstrom, and beta = 91.80 (2)-degrees. Compound 2 crystallizes in an orthorhombic system, space group P2(1)2(1)2(1), with z = 4, a = 9.3320 (10) angstrom, b = 9.768 (2) angstrom, and c = 30.581 (6) angstrom. Compound 3 belongs to the monoclinic system, space group P2(1)/n, with z = 4, a = 18.81 (3) angstrom, b = 19.25 (2) angstrom, c = 18.93 (2) angstrom, and beta = 112.8 (1)-degrees.