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The reaction of InBr with CH2Br2 in 1,4-dioxane or acetonitrile yields the corresponding solvate of Br2InCH2Br, which on reaction with E(C6H5)3 (E=P, As, Sb) gives the indium(III)-Group 15 dimetallo-methane derivatives, Br3InCH2E(C6H5)3. The crystal structures of the two related compounds (E=As, Sb) have been determined by X-ray crystallography. For Br3InCH2As(C6H5)3, cell constants a=15.553(7), b=21.646(8), c=12.920 (10) A; space group Pbca, Z=8, R=0.064, Rw=0.054, and for Br3InCH2Sb(C6H5)3, a=15.439(6) A, b=22.016(4) c=13.138(5) A; space group Pbca, Z=8, R=0.062, Rw=0.049. Results are also reported for I3InCH2As(C6H5)3 (cell constants a=12.0122(2), b=15.8526(3), c=13.4180(3) A, β=109.933(1)°; space group P21/n, Z=4, R=0.0481, Rw=0.0431) and Br3InCH2N(C2H5)3 (a=7.362(2), b=14.700(2), c=13.049(1) A, β=98.90(1)°; space group P21/n, Z=4, R=0.0418, Rw=0.0368). The structural results are compared with those for other organoindium ylids with the same general structure Br3InCH2L (L=P(C6H5)3; 1,1,3,3,-tetramethyl-2-thiourea; N,N,N′,N′-tetramethylethanediamine). Semi-empirical quantum mechanical calculations, using the PM3 method, were carried out on the series Br3InCH2E(C6H5)3 (E=P, As, Sb), and the calculated structural parameters are compared with the values determined by X-ray crystallography. The presence of an ylid ligand H2Cδ−δ+E(C6H5)3 in the organoindium compounds is confirmed. Mass spectra and thermogravimetric analysis strongly suggest that the thermal decomposition of the compounds occurs via fission of the indiumcarbon bond, leading to the corresponding ylid, which can be trapped by reacting the X3InCH2E(C6H5)3 compounds with HBr to produce the onium derivative [CH3E(C6H5)3]+ [InX4]− (E=P, As; X=Br, I). |
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