O. T. Beachley

Synthesis and Characterization of Amphoteric Ligands Including the Crystal and Molecular Structure of ((Me3SiCH2)2InPPh2)2.

Abstract The new amphoteric ligands (Me3SiCH2)2GaPPh2, (Me3SiCH2)2InPPh2, and (Me3CCH2)2InPPh2 have been prepared and characterized by elemental analyses, cryoscopic molecular weight measurements and 1H NMR, 31P NMR and IR spectroscopic data. An X-ray structural study was carried out to define the nature of [(Me3SiCH2)2InPPh2]2 in the solid state. The compounds were prepared either by a thermolysis reaction between the group 13 metal trialkyl and PPh2H or by a metathetical reaction between the dialkylmetal halide and KPPh2. Cryoscopic molecular weight measurements and 31P NMR spectroscopic data demonstrate that the new compounds exist as monomer-dimer equilibrium mixtures in benzene solution. The colorless crystal of [(Me3SiCH2)2InPPh2]2 contains two discrete molecules of the dimer in each unit cell. The compound crystallizes in the triclinic space group P 1 , with unit cell dimensions of a 10.323(4), b 11.113(5), c 21.509(8) A, α 83.85(5), β 86.66(6), γ 83.27(5)° and πcalcd 1.29 g cm-3. Full matrix least-squares refinement led to a final R value of 0.035 for 3787 observed reflections. The molecule contains four-membered indium-phosphorus rings.

Silicone grease as a precursor to a pseudo crown ether ligand: crystal structure of [K+]3[K(Me2SiO)7+][InH(CH2CMe3)3–]4

The crystallization of K[InH(CH2CMe3)3] from heptane in the presence of silicone grease led to the formation of the title compound, in which one potassium cation is surrounded by a planar cyclo-(Me2SiO)7 ligand; K+⋯ O distances range from 2.86(3) to 2.99(4)A.

(Tert-butyl)cyclopentadienylindium(I), In(C5H4CMe3): synthesis, characterization and X-ray structural study

Abstract The indium(I) compound, In(C 5 H 4 CMe 3 ), has been prepared from the corresponding lithium cyclopentadienyl reagent Li(C 5 H 4 CMe 3 ) and InCl in OEt 2 . Characterization data have included partial elemental analyses (C, H), physical properties, IR, 1 H NMR and mass spectroscopic data, oxidation reactions with dilute aqueous HCl and a single-crystal X-ray structural study. The colorless crystal of In(C 5 H 4 CMe 3 ) consists of infinite zigzag chains. There are no interstrand In⋯In interactions. The compound crystallizes in the monoclinic space group P 2 1 / n with four formula units in the unit cell with dimensions of a 6.139(1), b 9.765(6), c 15.543(3) A, β 92.87(1) and ϱ calcd 1.68 g/cm 3 .

Transition-metal complexes of organoaluminum phosphides. Synthesis, characterization, and crystal and molecular structure of Cr(CO)5(PPh2Al)(CH2SiMe3)2.NMe3

Abstract : The reactions of organoaluminum phosphides with a variety of transition metal carbonyl complexes containing labile ligands have been investigated. The reaction of Cr(CO)5NMe3 with (Me3SiCH2)(2AlPh2) in benzene solution leads to the formation of Cr(CO)5(PPh2Al(CH2SiMe3)2. NMe3), a fully characterized new compound. An x-ray structural study has identified discrete isolated molecules. Diffraction data were collected with a Syntex P2 sub 1 diffractometer and the structure was refined to R sub F = 6.4% for all 4948 reflections. There are no abnormally short intermolecular contacts. The unusual features identified in the investigation are the long bond distances for Al-P of 2.485(1)A and Cr-P of 2.482(1)A. The Al-N bond seems to be normal. The geometry about the tetrahedrally coordinated phosphorus atom is decidely irregular. Similarily, the aluminum atom has a rather distorted tetrahedral environment.

Gallium and indium compounds containing three different substituents. Crystal and molecular structure of [(Me3CCH2)ClGaPPh2]3

Abstract Three new heavier group 13 element compounds containing three different substituents, (Me 3 CCH 2 )ClGaPPh 2 , (Me 3 CCH 2 )BrGaPPh 2 and (Me 3 CCH 2 )ClInPPh 2 , have been prepared and characterized. All compounds were characterized by partial elemental analysis, cryoscopic molecular weight studies in benzene solution, and NMR and IR spectroscopic data. All three compounds exist as trimeric molecules in solution. NMR spectral data were consistent with the presence of multiple isomers of the trimers. The compound [(MC 3 CCH 2 )ClGaPPh 2 ] 3 crystallizes in the acentric space group Pn 2 1 a with a = 17.741(9) A, b = 13.942(6) A and c = 21.574(8) A. Diffraction data were collected on an Enraf-Nonius CAD-4 diffractometer, and the structure was refined to R = 4.6% and R w = 6.0% for those 2971 reflections with [ F o >s- 5σ( F o )]. The GaP six-membered ring has a typical chair conformation with the bulky neopentyl groups occupying the E,A,A, positions. Distances of interest include GaCl = 2.209(4), 2.219(4) and 2.220(4) A and GaP(bridging) which range from 2.414(3) A to 2.433(4) A.

The chemistry of diphenylphosphine adducts of tris(neopentyl) and tris(trimethylsilyl-methyl)gallium and -indium including the crystal and molecular structure of (Me3CCH2)3Ga·P(H)Ph2

Abstract The adducts (Me3CCH2)3Ga·P(H)Ph2 and (Me3SiCH2)3Ga·P(H)Ph2 have been prepared as crystalline solids at room temperature and characterized by cryoscopic molecular weight measurements in benzene solution and 1H NMR, 31P NMR and IR spectroscopic data. The molecular weight studies demonstrate that both adducts are extensively dissociated in solution and that Ga(CH2CMe3)3 is a stronger Lewis acid than Ga(CH2SiMe3)3. An X-ray structural study defined the nature of (Me3CCH2)3Ga·P(H)Ph2 in the solid state. The colourless crystal contains two discrete molecules in each unit cell. The compound crystallizes in the triclinic space group P 1 with unit cell dimensions of a = 9.564(8), b = 12.208(5), c = 12.946(9) A, α = 100.00(5), β = 100.41(8), γ = 102.97(7)° and Dcalc = 1.10 g cm−3. The adduct has a relatively long GaP distance of 2.683(5) A and the α-carbon atoms of the substituents on gallium and phosphorus are essentially but not perfectly eclipsed. The syntheses of (Me3CCH2)3In·P(H)Ph2 and (Me3SiCH2)3In·P(H)Ph2 were attempted but room temperature elimination reactions, which produced CMe4 and SiMe4, respectively, and the appropriate organoindium phosphides, precluded the isolation of adducts. Simple kinetic studies revealed that In(CH2CMe3)3-P(H)Ph2 eliminated CMe4 at 17°C significantly faster than In(CH2SiMe3)3-P(H)Ph2 produced SiMe4.

Ligand redistribution reactions of Me2Ga(C5H5) and MeGa(C5H5)2

Abstract The compounds Me2Ga(C5H5) and MeGa(C5H5)2 have been prepared by ligand redistribution reactions between appropriate stoichiometric quantities of Ga(C5H5) and GaMe3. Both compounds have been demonstrated by 1H NMR spectral studies to be unstable in solution and to form symmetrized products by ligand redistribution reactions. Thus, Me2Ga(C5H5) forms GaMe3 and MeGa(C5H5)2 as primary products whereas MeGa(C5H5)2 decomposes to Ga(C5H5)3 and Me2Ga(C5H5). The compound Me2Ga(C5H5) has also been shown to serve as a cyclopentadienyl transfer reagent as it reacts with FeCl2 to form Fe(C5H5)2 and Me2GaCl.

CHARACTERIZATION OF GALLIUM-NITROGEN ADDUCTS BY X-RAY STRUCTURAL AND NMR SPECTRAL STUDIES. CRYSTAL STRUCTURE OF [(PhMe2CCH2)2GaCI]2 AND OF ITS MONOMERIC t-BUTYLAMINE ADDUCT, (PhMe2CCH2)2GaCI[NH2(t-Bu)]

Abstract The nature of [(PhMe2CCH2)2GaCl]2 and its adducts with NH2(t-Bu) and NH2(n-Pr) have been investigated. [(PhMe2CCH2)2GaCl]2 crystallizes in the monoclinic space group P21/c with a=11.2495(16)Å, b = 21.4977(32)A, c = 7.8337(15)Å, β = 93.489(14)°, V= 1891.0(5)Å3 and D(calcd.)= 1.305 Mg/m3 for Z = 2. The structure was refined to R(F) = 4.2% for 1672 reflections above 6[sgrave](F). The molecule has perfect Ci symmetry, a planar Ga(μ-Cl)2Ga core and an expanded C(α)-Ga-C(α) angle of 137.9(3)° between the neophyl ligands. (PhMe2CCH2)2-GaCl[NH2(t-Bu)] crystallizes in the monoclinic space group P21/n with a = 6.4023(10) A, b= 17.4274(25) A, c = 22.2389(38) Å, β = 94.939(13)°, V= 2472.2(7)Å3 and D(calcd.) = 1.225 Mg/m3 for Z = 4. This structure was refined to R(F) = 3.9% for 1700 reflections above 6[sgrave](F). The crystal structure is stabilized by intermolecular Cl … H-N hydrogen bonds and the central Ga(III) atom has a distorted tetrahedral geometry. A benzene solution of (PhMe2-CCH2)2GaCl[NH2(t-Bu)] is in equilibrium with [(PhMe2CCH2)2GaCl]2[NH2(t-Bu)] and free amine according to 1HNMR studies. In contrast to this, a solution of (PhMe2CCH2)-GaCl2[NH2(t-Bu)] is in equilibrium with [(PhMe2CCH2)GaCl2]2[NH2(t-Bu)], free [(PhMe2-CCH2)-GaCl2]2 and free amine. Solutions of (PhMe2CCH2)2GaCI[NH2(n-Pr)] and (PhMe2CCH2)GaCl2[NH2(n-Pr)] show no evidence for similar equilibria.

Synthesis of an organogallium(I) compound [Ga(CH2CMe2Ph)]n with EPR spectral evidence for gallium clusters

Abstract The organogallium(I) compound [Ga(CH 2 CMe 2 Ph)] n has been prepared by the reduction of Ga(CH 2 CMe 2 Ph) 2 Cl by using either sodium or lithium with naphthalene in THF. The yellow dihydronaphthalene gallium(III) intermediate M 2 {C 10 H 8 [Ga(CH 2 CMe 2 Ph) 2 Cl] 2 } initially formed at −78°C but then decomposed at higher temperatures to form [Ga(CH 2 CMe 2 Ph)] n , Ga(CH 2 CMe 2 Ph) 3 and MCl. EPR spectra, which were recorded as the two yellow intermediates Na 2 {C 10 H 8 [Ga(CH 2 CMe 2 R) 2 Cl] 2 } (R=Ph, Me) decomposed, indicated the presence of radicals. The first and second derivatives of the EPR signals, line-widths, g -values and hyperfine coupling constants are consistent with the radicals being clusters of organogallium species. The experimental spectra were simulated by the superposition of two spectra, a single Gaussian shaped line with a peak-to-peak width of 14 mT (92%) with the spectrum of five equivalent gallium nuclei, A =2.1 mT (8%). The even number of lines observed in the experimental spectra indicate an odd number of gallium nuclei with at least five being required to give the number of observed lines.