REACTION OF SULFUR WITH GA-C BONDS - SYNTHESIS AND CHARACTERIZATION OF [PYRGAS](3) FORMED FROM GA(S(2)R)(3) (R=ET, ME)

The reactions of Ga(CH2CH3)(3) With variable amounts of elemental sulf ur, S-8, in toluene or benzene at different temperatures result in the insertion of sulfur into the Ga-C bonds to form the compounds Ga[(S-S )CH2CH3](3) (I) and Ga[(S-S-S)CH2CH3](3) (II). Compound I was isolated from the reaction at low temperature while at room temperature; compo und II was the major product. Compound II exhibited the maximum extent of sulfur insertion even when the reactions were carried out with mor e than 9.0 equiv of sulfur. The reactions of Ga(CH3)(3) with various a mounts of sulfur in toluene or benzene only result in the formation of compound III, Ga[(S-S)CH3](3). In pyridine at -30 degrees C, deinsert ion of the sulfur atoms from Ga-S-S-C bonds was observed for the first time from compounds I and III resulting in formation of the six-membe red Ga-S ring compounds IV, [PyEtGaS](3), and V, [PyMeGaS](3), respect ively. Compounds IV and V were characterized by H-1 NMR, C-13 NMR, ele mental analyses, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound IV crystallized in the monoclinic space group P2 (1)/n, with a = 9.288(2) Angstrom, b = 14.966(2) Angstrom, c = 19.588( 3) Angstrom, beta = 90.690(10)degrees, and Z = 4. Compound V crystalli zed in the monoclinic space group P2(1)/c, with a = 10.385(1) Angstrom , b = 15.300(2) Angstrom, c = 15.949(2) Angstrom, beta = 107.01(1)degr ees, Z = 4, unit cell volume = 2423.5(5) Angstrom(3), R = 0.030, and R (w) = 0.026. The sulfur insertion reaction pathway was investigated by time-dependent and variable-temperature H-1 NMR spectroscopy.