Charles H. Lake

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.

Structural studies on ruthenium carbonyl hydrides: XVIII. Synthesis and characterization of (μ-H)Ru3(μ3-η3-XCCRCR′)(CO)9—n(PPh3)n complexes. Crystal structures of (μ-H)Ru3(μ3-η3-Et2NCCHCMe)(CO)8(PPh3) and (μ-H)Ru3(μ3-η3-MeOCCMeCMe)(CO)7(PPh3)2·2CH2Cl2

Substitution products HRu3(μ3-η3-XCCRCR′)(CO)9—n(PPh3)n (X  OMe, R  R′  Me, n = 1–3; X  OMe, R  H, R′  OEt, n = 2, 3; X  NEt2, R  H, R′  Me, n = 1, 2) were prepared by using ONMe3-induced ligand substitution. The products were characterized by spectroscopic methods. In addition, (μ-H)Ru3(μ3-η3-Et2NCCHMe)(CO)8(PPh3) (Mo Kα, 2θ 5.0–50.0°, Rf 5.22% for all 6,374 reflections, 2.62% for those 4,306 reflections with | Fo | ⪢ 6σ( | Fo | )) and (μ-H)Ru3(μ3-η3-MeOCCMeCMe)(CO)7(PPh3)2·2CH2Cl2 (Mo Kα, 2θ 8.0–45.0°, RF 9.52% for all 6,798 reflections, 6.69% for those 3,795 reflections with | Fo | ⪢ 6σ( | Fo |)) were characterized by single-crystal X-ray diffraction. Both compounds crystallize in the triclinic space group P1, with a 11.277(2) A, b 11.899(1)A, c 15.638(2)A, α = 70.56(1)°,β = 85.23(1)°, γ = 66.00(1)°, V = 1802.8(4) A3, and Z = 2 for the former and a = 12.960(2) A, b = 13.040(2) A, c = 17.683(3) A, α = 98.81(1)°, β = 94.50(1)°, γ = 116.50(1)A, V = 2606.2(8) A3, and Z = 2 for the latter. In each case the PPh3 ligands are coordinated cis to the bridging hydride and to the sigma RuC bond.

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, characterization and redox properties of mixed phosphine nitroruthenium(II) complexes. crystal structure of trans-[Ru(NO2)(terpy)-(PMe3)(PPh3)][ClO4]·H2O

The mixed phosphine complexes trans-[Ru(NO2)(terpy)(PMe3)(PR3)][ClO4](terpy = 2,2′ : 6′,2″-terpyridine; R = Et, Pr, Bz or Ph) were synthesized in high yields by a stepwise addition of each phosphine. These syntheses demonstrate the utility of ruthenium(II) in the preparation of mixed phosphine complexes. The stereochemistry of trans-[Ru(NO2)(terpy)(PMe3)(PPh3)][ClO4]·H2O was confirmed by a single-crystal X-ray diffraction study. This species crystallizes in the monoclinic space group P21/c with a= 11.0199(15), b= 18.3888(28), c= 19.3089(25)A, β= 112.845(9)° and Z= 4. The two phosphine ligands are mutually trans, with P–Ru–P 177.5(1)°. The relative redox stabilities of the mixed phosphine complexes and a related series of trans-[Ru(NO2)(terpy)(PR3)2][ClO4](R = Et, Pr, Bz or Ph) complexes were evaluated using cyclic voltammetric peak current ratios (ipc/ipa) for the ruthenium(III)–ruthenium(II) couples. The rate constants for nitroruthenium(III) decomposition were calculated from the ipc/ipa data and the contributions of electronic (E) and steric (S) factors to its rate of decomposition were determined using the relationship ln k=aE+bS+c. The average ratio of steric to electronic ligand effects on ln k is approximately 30 : 70.

Alkyl for hydride exchange between alane-trimethylamine and group IVB metal alkryls

Abstract Reaction of equimolar amounts of AlH 3 ·NMe 3 and M(CH 2 SiMe 3 ) 4 , in benzene (for M=Zr, Hf) led to exchange of all three AlH bonds for AlCH 2 SiMe 3 bonds and isolation of Al(CH 2 SiMe 3 ) 3 ·NMe 3 The latter compound crystallized in the P 1 space group, a =9.535(2), b =10.913(2), c =12.273(2) A, α=88.03(1), β=86.03(1), γ=86.93(1)° U =1271.6(4) A, D c =002 g cm t-3 , Z =2, μ(Mo K α)=0.217 mm t-1 , F (000)=424. Similar reactions between AlH 3 ·NMe 3 and Cp 2 ZrR 2 (R=CH 3 , CH 2 SiMe 3 ) yielded Cp 2 ZrH 2 and AlR 3 ·NMe 3 . Reaction of AlH 3 ·NMe 3 with Zr(CH 2 Ph) 4 produced Al(CH 2 Ph) 3 ·NMe 3 .

Structural studies on ruthenium carbonyl hydrides

The complex (μ-H)Ru3(CO)10(μ-SEt) crystallizes in the centrosymmetric orthorhombic space group Pbca (No. 61) with a 17.361(2), b 12.804(4), c 17.484(3) A, V 3886.5(14) A3 and Z = 8. Diffraction data (Mo-Kα, 2θ = 4.0-45.0°) were collected with a Syntex P21 automated diffractometer and the structure was solved and refined to R 5.9% for 1800 reflections with |Fo| > 3σ(| Fo|) (R4.1% for those 1413 reflections with |F0| > 6σ(|F0|)). The complex contains a triangular cluster of ruthenium atoms in which Ru(2) and Ru(3) are each linked to three terminal carbonyl ligands while Ru(1) is linked to four. Additionally Ru(2) and Ru(3) are bridged by a SEt ligand [Ru(2)S 2.389(4), Ru(3)S 2.391(4) A and Ru(2)SRu(3) 73.0(1)°] and a hydride ligand. The di-bridged RuRu linkage (Ru(2)Ru(3) 2.843(1) A is slightly longer than the non-bridged bonds (Ru(1)-Ru(2) 2.831(2) and Ru(1)Ru(3) 2.825(1) A).