- Anionic Cadmium Complexes Containing the Bulky Tris(trimethylsilyl)germyl and Tris(trimethylsilyl)silyl Ligands
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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.
- Mallela, Siva P.,Schwan, Frank,Geanangel
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- Silylgermylpotassium compounds
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By the reactions of potassium tert-butoxide with a number of oligosilylgermanes, oligosilylgermylpotassium compounds were generated. Their chemistry very much resembles that of the analogous oligosilylsilylpotassium compounds. However, the ease of formation is even more pronounced in the case of the germyl anions. Again potassium tert-butoxide proved to be a highly selective metalation reagent, leading to no unwanted cleavage of Si - Ge or Ge - Ge bonds. A number of new and potentially useful oligosilylgermyl mono- and dianions have been prepared in this manner.
- Fischer, Jelena,Baumgartner, Judith,Marschner, Christoph
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- Thermal and photochemical reactions of phenylethynyltris-(trimethylsilyl) germane
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The thermal and photochemical behavior of phenylethynyltris(trimethylsilyl) germane (1) has been reported. The thermolysis of 1 in the absence of a trapping agent in a sealed glass tube at 240 °C for 6 h gave 1,3-bis(trimethylsilyl) -1-tris(trimethylsilyl)germyl-1-germaindene (2) in 18% yield, together with phenyl(trimethylsilyl)acetylene in 60% yield. Similar thermolysis of 1 in the presence of 2,3-dimethylbutadiene afforded 3,4-dimethyl-1,1-bis(trimethylsilyl)- 1-germacyclopent-3-ene (3) in 62% yield, along with phenyl(trimethylsilyl) acetylene. When 1 was irradiated with a low-pressure mercury lamp in the presence of a large excess of 2,3-dimethylbutadiene at room temperature for 10 min, compound 3 was obtained in 11% yield, in addition to 17% of phenyl(trimethylsilyl)acetylene and 31% of the starting compound 1. The photolysis of 1 in the absence of a trapping agent under the same conditions afforded phenyl(trimethylsilyl)acetylene as the sole volatile product. The DFT calculations were carried out to investigate the reaction mechanisms for the thermal reaction of 1 leading to the germaindene 2.
- Naka, Akinobu,Kajihara, Tomohito,Miura, Toshiko,Kobayashi, Hisayoshi,Ishikawa, Mitsuo
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- Preparation and structural characterization of trimethylsilyl-substituted germylzinc halides, (Me3Si)3GeZnX (X = Cl, Br, and I) and silylzinc chloride, R(Me3Si)2SiZnCl (R = SiMe3 and Ph)
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The trimethylsilyl-substituted germylzinc halides, (Me3Si) 3GeZnX (X = Cl, Br, and I), and silylzinc chlorides, R(Me3Si)2SiZnCl (R = SiMe3 and Ph) have been prepared and their molecular structures have been full determined by spectroscopic and single-crystal X-ray diffraction methods. The germylzinc halides and silylzinc chlorides have dimeric structures consisting of two μ-halogen atoms. The reactivity of germylzinc chloride with substrates is also examined.
- Nanjo, Masato,Oda, Takashi,Mochida, Kunio
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p. 100 - 108
(2007/10/03)
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- Preparation and structural characterization of bis[tris(trimethylsilyl)-germyl]zinc, [(Me3Si)3Ge]2Zn
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Bis[tris(trimethylsilyl)germyl]zinc, [(Me3Si)3Ge]2Zn, was prepared by the reaction of [tris(trimethylsilyl)germyl]lithium, (Me3Si)3GeLi(thf), with zinc chloride, ZnCl2, and by the reaction of tris(trimethylsilyl)germane, (Me3Si)3GeH, with diethylzinc, Et2Zn. The molecular structure of [(Me3Si)3Ge]2Zn was determined by spectroscopic and X-ray diffraction methods. In [(Me3Si)3Ge]2Zn, the two tris(trimethylsilyl)germyl ligands, (Me3Si)3Ge, are bonded in a linear fashion to the zinc atom and are staggered with respect to each other. The reactions of bis(germyl)zinc with substrates were also examined.
- Nanjo, Masato,Oda, Takashi,Mochida, Kunio
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p. 1261 - 1264
(2007/10/03)
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- Preparation and characterization of tris(trimethylsilyl)germylzinc chloride and bis[tris(trimethylsilyl)germyl]zinc
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The molecular structure of (Me3Si)3GeZnCl (1) has been determined by single-crystal X-ray diffraction. The germylzinc chloride 1 has a dimeric structure consisting of two μ-Cl atoms. The compound 1 reacted with (Me3Si)3GeLi in diethyl ether to give [(Me3Si)3Ge]2Zn (2), quantitatively. The structure of bis(germyl)zinc 2 has been also elucidated by X-ray diffraction.
- Nanjo, Masato,Oda, Takashi,Mochida, Kunio
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p. 108 - 109
(2007/10/03)
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- New small-ring cyclogermanes: syntheses and X-ray crystal structures
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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.
- Mallela, Siva P.,Hill, Sven,Geanangel
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p. 6247 - 6250
(2008/10/09)
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- New cyclic and acyclic silicon-germanium and silicon-germanium-tin derivatives
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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.
- Mallela,Geanangel
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p. 1115 - 1120
(2008/10/08)
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- SYNTHESIS OF SOME TRIS(TRIMETHYLSILYL)GERMYL COMPOUNDS
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A variety of compounds containing the tris(trimethylsilyl)germyl group were prepared and characterized spectroscopically.Photolysis of adamantoyltris(trimethylsilyl)germane failed to yield the isomeric germene: in CCl4 the photolysis appeared to occur by a Norrish type 1 process.
- Brook, A. G.,Abdesaken, F.,Soellradl, H.
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