The bimetallic cluster Cp'2Mo2Co&(CO)d (1) reacts with organic sulfur compounds, e.g. 'BUSH, Mez-CHCH~CHZSH, PhSH, tBuNCS, cis-2,3-dimethylthiirane, and thiophene, to give the cubane cluster Cpt2M02C02S4-(C0)2 (2) in high yield. With the thiols, theorganic productsare the parent hydrocarbons. The thiophenedesulfurization products are saturated and unsaturated C I -C~ hydrocarbons, and the thiocyanates produce RNC that reacts with 1 and 2 to form the carbonyl substitution products C~'~M O~C O~S~( C O )~( R N C ) and C~'~M O Z C O~S~( C O ) ( R N C ) , respectively. The cis-2,3-dimethylthiirane produces cis-Zbutene stereospecifically. The mechanistic implications are discussed, and the desulfurization reactions are compared to the hydrodesulfurization (HDS) reactions catalyzed by an alumina-supported Mo/Co/S composition.

The atmospheric pressure chemical vapor deposition of tin nitride thin films from tetrakis(dimethylamido)tin(IV) and ammonia precursors is reported. The films were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, and forward recoil spectrometry. The films were deposited on soda lime, borosilicate, and quartz glass and silicon substrates at substrate temperatures of 200-400 °C with growth rates up to 1000 A/min. The films were smooth, adherent, and chemically inert Rutherford backscattering analysis showed that the N/Sn ratio was 1.45-1.50. The ratio was independent of deposition temperature. The hydrogen concentration, measured by forward recoil spectrometry, ranged from 18 atom % at 200 °C to 15 atom % at 400 °C. Transmission electron microscopy revealed that the films deposited at 200 °C were amorphous whereas films deposited at 300 and 400 °C were polycrystalline. The films were conductive with resistivities in the range of (2-9) X 10'3 ft cm. A bandgap of 1.94-2.25 eV was estimated from transmission spectra.

Fire-induced pressures have not been considered dangerous in building fires, but the situation may be changing as building envelopes become increasingly air-tight. In this study, we investigate whether this can change the fire development and pose new risks for structural and evacuation safety. We used experiments to validate the numerical models, and models for simulating the fire development in buildings with different airtightness levels. The simulations considered air permeability values typical for traditional, modern and Near-Zero buildings. Three different smoke damper configurations were studied, and the fire growth rates were varied from medium to ultra-fast. The results showed that transitioning from traditional and modern buildings to Near-Zero buildings can sufficiently increase the peak overpressures from fast-growing fires to cause structural damage. Conditions were identified for avoiding excessively high overpressures, while preventing smoke from spreading through the ventilation system.

The preparation and molecular structures of the clusters Cp'3Mo3CoS4(CO), Cp'3M03-FeS4(SH), and Cp'zMozCozS3(PPh)(CO) are reported along with the structure of the previously known cluster Cp'zMozCozS4(CO)~. All these compounds have a tetrahedron of metal atoms at distances corresponding to metal-metal single bonds with p3-S ligands capping the triangular metal faces of the tetrahedron to give a n overall cubanelike geometry to the clusters. In Cp'zMo&ozS3(PPh)(CO), there is one p3-PPh ligand in addition to three pa-S ligands.

for Ph2Hg. K 2 is large for all three at -105 "C.ISWe have carried out a quantitative measurement of K2 for PhI. all species [(PhLi),, (PhLi),, PhI, Ph21-Li+] are in rapid equilibrium (above coalescence). We have measured values for AH" and ASo for the phenyllithium monomer-dimer equilibrium,I6 so the population of the other species (Phl, Ph21-Li+) can be calculated from the average chemical shift of the ortho carbon in the I3C NMR spectrum. We obtained AH" = -9.9 f 0.6 kcal/mol and AS" = -44 f 9 eu for eq 2." Thus K2 is 0.02 M-' at 0 "C (a solution 0.1 M in PhLi and Phl is 0.1% associated), 30 M-' at -78 "C (44% associated), and 1780 M-' at -105 "C (92% associated). The corresponding association constant K2 for Ph2Te is almost the same as for Phl, as shown by an experiment in which 1 equiv of PhI was added to a solution of Ph3Te-Li+ in T H F at -105 0C.20 Half of the Ph3Te-Li+ was converted to Ph21-Li+. Summary. Iodine, tellurium, and mercury ate complexes have been characterized as intermediates in the PhLi/Ph,M (M = I, Te, Hg) exchange reaction in T H F solution at low temperatures. Monomeric phenyllithium is the reactive species in the Li/I and Li/Te exchanges. The formation constant for Ph21-Li+ is strongly temperature dependent, consistent with the powerful solvent-ordering capacity of a solvent-separated ion pair.'* (20) Kinetic experiments such as depicted in Figure 1 of ref la show that K2-s for Te and I are also identical within experimental error at -78 OC.