The first example of a structurally characterized gallium thiocarboxylate compound, Ga(SCOMe)zMe(dmpy) 1 (dmpy = 3,5dimethylpyridine), is synthesized and used to deposit high-purity, crystalline gallium sulfide thin films by aerosol-assisted chemical vapour deposition at low temperatures.

Gallium and indium chalcogenide compounds are a family of semiconductors that have attracted attention in recent years due to their interesting optoelectronic properties.['4] Such materials can be classified as mid-bandgap semiconductors, e.g., P-In& (2.07 eV), Ins (2.44 eV) as compared to materials such as GaAs (1.42eV, narrow bandgap) and ZnS (3.68eV, wide bandga~)!~-~] The few reports of the chemical vapor deposition (CVD) of thin films of III/VI materials from single-source precursors in the literature involve the use of the compounds ['BU~I~(S'BU)]~, [MezIn(S'Bu)l2, and R2MS2CNEt2 (M = In, Ga; R = Me, Et or neopentyl), as precursors.l4-"] Indium sulfide films were deposited from these compounds at substrate temperatures between 350°C and 550°C. Here we report the low-temperature deposition of crystalline P-InzS3 thin films, a high temperature, high pressure phase of indium sulfide, from a novel indium thiocarboxylate compound 1, [HL]@[In(SC0CH3)4lQ, (L = 3,5-dimethylpyridine), as single-source precursor. This species was prepared as part of a general design strategy[12] of precursors to metal sulfides in which ligands are incorporated that can undergo quantitative elimination to form the corresponding metal sulfide and thioacetic anhydride with dissociation of L according to Equation 1, thus providing a pathway to produce high purity metal sulfides.InEt3 was reacted with an excess of thioacetic acid in benzene followed by addition of 3,s-dimethylpyridine in an inert atmosphere glove box (see Experimental section).We thank the Office of Naval Research for funding this research, the National Science Foundation Chemical Instrumentation Program for the purchase of a low-field NMR spectrometer and the Dreyfus Foundation and AFOSR for the purchase of a X-ray powder diffractometer. We thank Dr. Paolina Atanasova for obtaining the AES data.0 VCH Verlugsgesellschaft mbH, 0-69469 Weinheim, I996

The reactions of Ga(CH(2)CH(3))(3) with variable amounts of elemental sulfur, 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)CH(2)CH(3)](3) (I) and Ga[(S-S-S)CH(2)CH(3)](3) (II). Compound I was isolated from the reaction at low temperature while at room temperature; compound II was the major product. Compound II exhibited the maximum extent of sulfur insertion even when the reactions were carried out with more than 9.0 equiv of sulfur. The reactions of Ga(CH(3))(3) with various amounts of sulfur in toluene or benzene only result in the formation of compound III, Ga[(S-S)CH(3)](3). In pyridine at -30 degrees C, deinsertion 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-membered Ga-S ring compounds IV, [PyEtGaS](3), and V, [PyMeGaS](3), respectively. Compounds IV and V were characterized by (1)H NMR, (13)C NMR, elemental 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) Å, b = 14.966(2) Å, c = 19.588(3) Å, beta = 90.690(10) degrees, and Z = 4. Compound V crystallized in the monoclinic space group P2(1)/c, with a = 10.385(1) Å, b = 15.300(2) Å, c = 15.949(2) Å, beta = 107.01(1) degrees, Z = 4, unit cell volume = 2423.5(5) Å(3), R = 0.030, and R(w) = 0.026. The sulfur insertion reaction pathway was investigated by time-dependent and variable-temperature (1)H NMR spectroscopy.