No abstract

The structural, electronic, and thermochemical properties of indium compounds which are of interest in halide transport and organometallic chemical vapor deposition processes have been studied by ab initio and statistical thermodynamic methods. The compounds reported include:  indium halides and hydrides (InF, InCl, InCl3, InH, InH2, InH3); indium clusters (In2, In3); methylindium, dimethylindium, and their hydrogen derivatives [In(CH3), In(CH3)H, In(CH3)H2, In(CH3)2, In(CH3)2H]; dimethylindium dimer [In2(CH3)4] and trimethylindium [In(CH3)3]; dehydrogenated methyl-, dimethyl-, and trimethylindium [In(CH3)2CH2, In(CH3)CH2, In(CH2)]; trimethylindium adducts with ammonia, trimethylamine and hydrazine [(CH3)3In:NH3, (CH3)3In:N(CH3)3, (CH3)3In:N(H2)N(H2)]; dimethylamino-indium and methylimino-indium [In(CH3)2(NH2), In(CH3)(NH)]; indium nitride and indium nitride dimer (InN, In2N2); indium phosphide, -arsenide, and -antimonide (InP, InAs, InSb). The predicted electronic properties are based on density functional theory calculations; the calculated thermodynamic properties are reported following the format of the JANAF (Joint Army, Navy, NASA, Air Force) Tables. Equilibrium compositions at two temperatures (298 and 1000K) have been analyzed for groups of competing simultaneous reactions.

Crystallization of 1,1-dicyano-2-(4-hydroxyphenyl)-ethene (I) and 1,1-dicyano-2-(4-hydroxy-3-methoxyphenyl)-ethene (II) with L-proline (III) and L-tartaric acid (IV) was carried out. Compound I formed cocrystals with L-proline I‚III. However, cocrystallization of II was unsuccessful; instead in the presence of III or IV formation of two conformational polymorphs IIa and IIb was observed. In cocrystals I‚III, hydrogen bonded chains of proline molecules with molecules of I attached to them were found. Similar synthons were found in the literature in other proline-containing crystals, and we believe that it is possible to use these acentric supramolecular associates in crystal engineering of nonlinear optical materials. Possible reasons for the formation of two conformational polymorphs of compound II are discussed based on the results of X-ray analysis, molecular and crystal structure energy calculations, and thermal behavior of compound II.