104164-57-0Relevant academic research and scientific papers
New small-ring cyclogermanes: syntheses and X-ray crystal structures
Mallela, Siva P.,Hill, Sven,Geanangel
, p. 6247 - 6250 (2008/10/09)
Reaction of GeCl2·dioxane with 2 equiv of Li(THF)2.5Ge(SiMe3)3 in hexane afforded moderate yields of two cyclopolygermanes. A cyclotrigermane, (Ge(SiMe3)2)3, was characterized by NMR spectra, elemental analyses, and an X-ray crystal structure determination. It crystallized from pentane in the R3?c space group (rhombohedral) with a = 19.294(3) A?, α = 31.89(1)°, V= 1781 A°3, and Z = 2. The Ge3 core consisted of an equilateral triangle with a Ge-Ge distance of 2.460(1) A°, the shortest so far measured in cyclotrigermanes. The second product was tentatively identified by its NMR spectra as a cyclotetragermane, ((Me3Si)3GeGeCl)4, and this was confirmed by elemental analyses and an X-ray structure determination on the yellow crystals formed from pentane. The product was found to crystallize as a complex with two molecules of Ge(SiMe3)4 in the F23 (cubic) space group with a = 22.7731(3) A?, V = 11 810.5 A?3, and Z = 8. The Ge4 core consisted of a nonplanar four-membered ring (fold angle = 18.7°) disordered over three positions related by 3-fold symmetry. In the assumed ordered structure, ring Ge-Ge distances averaged 2.503 A?. When the reaction was repeated with GeCl2·dioxane and 2 equiv of Li(THF)3Si(SiMe3)3, the known disilagermirane, (Me3Si)2Ge(Si(SiMe3)2)2, was isolated (66% yield) along with a small yield of the known cyclotetragermane, ((Me3Si)3SiGeCl)4. Reaction of GeI2 with Li(THF)2.5Ge(SiMe3)3 gave only traces of the cyclotrigermane.
Anionic Cadmium Complexes Containing the Bulky Tris(trimethylsilyl)germyl and Tris(trimethylsilyl)silyl Ligands
Mallela, Siva P.,Schwan, Frank,Geanangel
, p. 745 - 748 (2008/10/09)
The first triiodo-bridged tris(trimethylsilyl)silyl- and tris(trimethylsilyl)germyldicadmium anionic complexes were prepared from CdI2 and 2 equiv of LiE(SiMe3)3 (E = Si and Ge) in hexane. The crystal structure of the germyl derivative 1 was determined. It crystallizes as a lithium salt from pentane in the Cmcm space group (orthorhombic) with a = 14.494(2), b = 16.334(3), and c = 27.361 ?, V = 6478 ?3, and Z = 4. The complex anion of 1, [(Me3Si)3GeCd(μ-I3)CdGe(SiMe 3)3-], exhibits two approximately tetrahedrally coordinated cadmiums with three iodides in trigonal bridging positions between the cadmiums. Efforts to prepare similar chloride-bridged structures were not fruitful.
New cyclic and acyclic silicon-germanium and silicon-germanium-tin derivatives
Mallela,Geanangel
, p. 1115 - 1120 (2008/10/08)
New Si-Ge and Si-Ge-Sn compounds bearing the bulky groups -E(SiMe3)3 (E = Si, Ge) were obtained by treatment of MCl4 (M = Ge, Sn) with either (THF)3LiSi(SiMe3)3 or (THF)2.5LiGe(SiMe3)3. The cyclic tetragermane [(Me3Si)3SiGeCl]4·C6H 6 crystallizes in the monoclinic space group C2/c with a = 21.835(7) A?, b = 26.342(9) A?, c = 14.464(4) A?, β = 103.45°, V = 8092 A?3, and Z = 4. The Ge4 ring was nonplanar with an average torsion angle of 17.2°. The tetragermane [(Me3Si)3GeGeCl2]2 was characterized by elemental analyses and NMR spectra, which were consistent with a linear tetragermane backbone for the molecule. Dichlorobis(tris(trimethylsilyl)germyl)-tin(IV), ((Me3Si)3Ge)2SnCl2, crystallizes in the monoclinic space group C2/c with a = 16.106(4) A?, b = 10.034(2) A?, c = 47.375(11) A?, β = 90.02°, V = 7656 A?3, and Z = 8. The coordination geometry around tin is extremely distorted with Ge-Sn-Ge = 142.1° and Cl-Sn-Cl = 98.8°. The three compounds were stable in air except ((Me3Si)3Ge)2SnCl2 was mildly hygroscopic. Reactions of the compounds with Li, LiAlH4, and (THF)2.5LiGe(SiMe3)3 were carried out, but no new products were identified. Treatment of LaCl3 with 3 equiv of (THF)3LiSi(SiMe3)3 afforded (THF)La(Si(SiMe3)3)2Cl as a very hygroscopic white solid. All attempts to substitute more than two -Si(SiMe3)3 groups on a central atom were unsuccessful.
