20991-88-2Relevant academic research and scientific papers
Inversion barriers of methylsilole and methylgermole monoanions
Pak, Youngshang,Chun Ko, Young,Sohn, Honglae
, p. 4161 - 4164 (2013/08/23)
Density functional MO calculations for the methylsilole anion of [C 4H4SiMe]- and methylgermole anion of [C 4H4GeMe]- at the B3LYP (full)/6-311+G* level (GAUSSIAN 94) were carried out and c
Platinum-catalyzed bis-germylation of alkynes with organodigermanes and cyclic oligogermanes
Mochida, Kunio,Wada, Tohru,Suzuki, Kaoru,Hatanaka, Wakako,Nishiyama, Yuriko,Nanjo, Masato,Sekine, Akiko,Ohashi, Yuji,Sakamoto, Masato,Yamamoto, Akio
, p. 123 - 137 (2007/10/03)
Hexamethyldigermane, Me3GeGeMe3, reacted with various alkynes in the presence of platinum complexes at 120 °C to afford Z-1,2-bis(germyl)ethenes in moderate to good yields. Terminal alkynes exhibit higher reactivities than internal ones. [Pt(acac)2] and [Pt(dba)2] serve as efficient catalysts, while [Pt(PPh3)4], [PtCl2(PPh3)2], and [Pt(dba)2]-phosphite were found to be inactive. Four- and six-membered cyclic oligogermanes, such as dodecamethylcyclohexagermane, (Me2Ge)6, reacted with alkynes in the presence of platinum catalysts to yield 1,4-digermacyclohexa-2,5-dienes in ca. 30% yield. The reactions of phenylacetylene with 1,2-digermacyclohexa-3,5-dienes afforded the corresponding 1,4-digermacycloocta-2,5,7-trienes in 93% yield. Bis(germyl)platinum complexes having various tertiary phosphine ligands have been prepared as models of a key intermediate in the above mentioned catalytic bis-germylation of alkynes, and their structures have been established by spectroscopic methods and X-ray crystallography. Bis(germyl)platinum complexes reacted with phenylacetylene to give the corresponding insertion products, germyl(germylvinyl)platinum species, whose structures have been determined by spectroscopic and X-ray analysis. Germyl(germylvinyl)platinum complexes were found to liberate a bis-germylation product of the alkyne upon heating. The result supports a mechanism involving the oxidative addition of a digermane to a Pt(0) complex, the insertion of an alkyne into one of the two Pt-Ge bonds to give a germyl(germylvinyl)platinum species, and the reductive elimination of the bis-germylation product of the alkyne. Evidence suggesting the extrusion of a germylene unit from the bis-germylplatinum species has been obtained, accounting for the generation courses of other by-products.
Ring contraction of 1,2-digermacyclohexa-3,5-dienes initiated by electron transfer reactions with TCNE
Mochida, Kunio,Shimizu, Hiromi,Nanjo, Masato
, p. 1226 - 1227 (2007/10/03)
The thermal reaction of 1,2-digermacyclohexa-3,5-dienes with tetracyanoethylene (TCNE) gave 1-germacyclopenta-2,4-diene as a germylene extrusion compound through a charge-transfer complex. The 1-germacyclopenta-2,4-diene was trapped with TCNE to give 5,5,6,6-tetracyano-7-germanor-bornene.
Electrochemical and photophysical properties of a series of group-14 metalloles
Ferman, Justin,Kakareka, Joseph P.,Klooster, Wim T.,Mullin, Jerome L.,Quattrucci, Joseph,Ricci, John S.,Tracy, Henry J.,Vining, William J.,Wallace, Scott
, p. 2464 - 2472 (2008/10/08)
A series of six group-14 dimethyl- or diphenyl-tetraphenylmetallacyclopentadienes were synthesized and characterized by their spectroscopic and electrochemical properties. The group-14 elements investigated were silicon, germanium, and tin. (The compounds are designated according to the heteroatom and the substituent on the heteroatom, i.e., SiMe, SiPh, SnPh.) Five of the six compounds luminesce in both the solid state and in solution. The emission maxima of SiPh, GePh, and SnPh are invariant to a change in the heteroatom, while for SiMe, GeMe, and SnMe there is a strong dependence of the emission maxima on the identity of the heteroatom. SiMe emits at a longer wavelength than GeMe, while SnMe is not luminescent. The dramatic luminescence difference between the two tin compounds was investigated. 13C NMR coupling to 119/117Sn, observed in both SnMe and SnPh, was used to make 13C NMR resonance assignments. Qualitative results of semiempirical molecular orbital calculations support the 13C NMR assignments. The crystal structure data for SnPh was obtained at 20 °C: a = 10.353(2) A?, b = 16.679(2) A?, c = 9.482(1) A?, α = 99.91(1)°, β = 106.33(1)°, γ = 77.80(1)° with Z = 2 in space group P1. It is proposed that the increased electron density at tin in SnMe is responsible for the deactivation of the emissive state. The presence of phenyl substituents in SnPh serves to stabilize the emissive state and luminescence is observed.
Tetraphenylzirkonacyclopentadien-Derivate als Synthone fuer Tetraphenylthiophenmonoxid und substituierte Germanole
Meier-Brocks, Frank,Weiss, Erwin
, p. 33 - 45 (2007/10/02)
Improved syntheses for the five-membered heterocycles 2,3,4,5-tetraphenylthiophene-1-monoxide (1), 1,1-dichloro-2,3,4,5-tetraphenylgermole (3) and 1,1-dimethyl-2,3,4,5-tetraphenylgermole (4) are reported.They make use of bis(η5-cyclopentadienyl)-2,3,4,5-tetraphenyl-1-zirconacyclopentadiene (2), easily prepared in a one-step reaction from Cp2ZrCl2, n-BuLi and diphenylethyne.Further reaction of 2 with SOCl2, GeCl4 or Me2GeCl2 yields the desired products and allows recovery of Cp2ZrCl2.Crystal structure analyses of 1 and 4 demonstrate folded five-membered rings with a diene system.Starting from 3 the following derivatives have been synthesized: Ph4C4Ge(CCR)2 (R = H, t-Bu, Ph), Ph4C4GeCl (10) and Ph4C4GeCl.Moreover spectral data (IR, 1H NMR, 13C NMR) of all compounds and the crystal structure of 10 are reported.
Chemistry of heavy carbene analogues R2M (M = Si, Ge, Sn). 16. Reactions of free dimethylgermylene with alkynes and their palladium catalysis
Billeb, Gilbert,Brauer, Hartmut,Neumann, Wilhelm P.,Weisbeck, Markus
, p. 2069 - 2074 (2008/10/08)
Free dimethylgermylene, Me2Ge (1), reacts with alkynes RC≡CR′ (3) to give a multitude of four-, five-, and six-membered germaheterocycles 4-6,8, containing one, two, or even three Ge atoms, or the acyclic 3-germapent-1-en-4-yne 7. The nature of R and R′ (H, alkyl, or aryl) determines whether 1,4-digermacyclohexa-2,5-dienes 4, 1-germacyclopenta-2,4-dienes 6, or 1,2,3-trigermacyclopent-4-ene8 5 are formed. Hexafluoro-2-butyne gives the corresponding 1,2-digermacyclobut-3-ene 8. The mechanisms of product formation are discussed. Germirenes 11 or, in special cases, the digermene Me2Ge=GeMe2 (10) and the cyclotrigermane (Me2Ge)3 (12) are proposed as intermediates. A number of alkynes 3 which do not form isolable products with 1 give compounds 4 or 6 when catalytic amounts of (Ph3P)4Pd are present.
Synthese de germoles par reaction de transmetallation (Groupe 4 (groupe 14))
Dufour, Pascal,Dartiguenave, Michele,Dartiguenave, Yves,Dubac, Jacques
, p. 61 - 69 (2007/10/02)
The transmetallation reaction of group 14 metallacyclopentadienes, Cp2EC4R'4 (E = Ti, Zr, Hf; R' = Ph, Me) with various halogermanes has been studied.The tetrahalides GeCl4 and GeBr4 undergo the E/Ge exchange reaction at room temperature, but the trihalides RGeCl3 and dihalides R2GeCl2 (R = Me, Ph) are less reactive.Some germoles were found to be unstable.A phenyl group on the germanium atom stabilizes the 2,3,4,5-tetramethylgermoles with a Ge-H (HPhGeC4Me4) or Ge-Cl bond (ClPhGeC4Me4).
SYNTHESE, REAKTIONEN UND STRUKTUR VON TRICARBONYL(1R,1R',2,3,4,5-TETRAPHENYL-1-GERMACYCLOPENTADIEN)EISEN-KOMPLEXEN
Jutzi, Peter,Karl, Alfons,Burschka, Christian
, p. 27 - 39 (2007/10/02)
The tricarbonyl(germacyclopentadiene)iron complexes VI-X are synthesized by the reaction of the germacyclopentadienes I-V with Fe(CO)5.In 1,1-dialkyl- and -diaryl-1-germacyclopentadiene complexes the Ge-C(exo) bond can be split by different element halide
