- Donor-acceptor molecular oligogermanes: Novel properties and structural aspects
-
The linear oligogermyl amide 2, Ph3GeGeMe2NMe2, was obtained by reacting Ph3GeLi with 1, Me2Ge(Cl)NMe2. The amide 2 was used for the synthesis of molecular oligogermanes 3, Ph3GeGeMe2Ge(C6F5)3, and 4, [Ph3GeGeMe2]2Ge(C6F5)2, containing electron donor (Me, Ph) and acceptor (C6F5) groups, by using a hydrogermolysis reaction in n-hexane. The molecular structures of 3 and 4 were studied by XRD. It was shown that in a crystal 3 forms wide channels, in which the solvated nonpolar n-hexane molecule is present. The NMR (1H, 13C and 19F), optical (UV/vis absorption, luminescence) and electrochemical (cyclic voltammetry) properties of both compounds were also studied. The impact of the substitution type by the electron withdrawing groups (at the terminal position, such as in 3, or within the compound, such as in 5), on the physical properties was also studied.
- Zaitsev, Kirill V.,Kharcheva, Anastasia V.,Lam, Kevin,Zhanabil, Zhaisan,Issabayeva, Guldana,Oprunenko, Yuri F.,Churakov, Andrei V.,Zaitseva, Galina S.,Karlov, Sergey S.
-
-
Read Online
- THE INTERACTION OF NICKELOCENE WITH BIS(TRIPHENYLGERMYL)CADMIUM
-
The reaction of bis(triphenylgermyl)cadmium with nickelocene proceeds through the displacement of a cyclopentadienyl ring and the formation of an organopolymetallic compound containing nine metal atoms: This is a new type of organometallic compound, containing Ni-Cd bonds.
- Titova, S. N.,Bychkov, V. T.,Domrachev, G. A.,Razuvaev, G. A.,Struchkov, Yu. T.,Zakharov, L. N.
-
-
Read Online
- Photodecompostion of the Oligogermanes nBu3GeGePh2GenBu3 and nBu3GeGePh3: Identification of the Photoproducts by Spectroscopic and Spectrometric Methods
-
The oligogermane nBu3GeGePh2GenBu3was photolyzed using UV-C light in the presence of acetic acid as a trapping agent and the photoproducts were identified using1H NMR spectroscopy, gas chromatography/electron-impact mass spectrometry, and high resolution accurate mass mass spectrometry. The products identified were the germanes nBu3GeH, nBu3GeOAc, and Ph2Ge(H)OAc (OAc = C2H3O2) and the digermane nBu6Ge2. This indicates that both germanium–germanium single bonds are cleaved homolytically upon irradiation to generate two nBu3Ge·radicals and the germylene Ph2Ge:. The digermane nBu3GeGePh3was also photolyzed under identical conditions, and in this case the photoproducts were identified as nBu3GeH, nBu3GeOAc, Ph3GeH, Ph3GeOAc and the digermanes nBu6Ge2and Ph6Ge2.
- Komanduri, Sangeetha P.,Schrick, Aaron C.,Feasley, Christa L.,Dufresne, Craig P.,Weinert, Charles S.
-
p. 3196 - 3203
(2016/07/14)
-
- Selective Synthesis and Derivatization of Germasilicon Hydrides
-
Mixed Si/Ge hydrides SixGeyHz are valuable precursors for the deposition of binary Si-Ge alloys. This work describes the synthesis and full characterization of the previously unknown germaisotetrasilane Ph3GeSi(SiH3)3 (2) on a multigram scale from the reaction of the lithium silanide LiSi(SiH3)3 with Ph3GeCl. The stability of the Si-Ge bond in 2 versus electrophiles and nucleophiles has been investigated with the primary aim of developing new approaches to mixed sila-H-germanes (H3Ge)xSi(SiH3)4-x. With 1 equiv of MeLi, 2 reacted cleanly under cleavage of one Si-Si bond to give Ph3GeSi(SiH3)2Li, which is a valuable synthon for further derivatization. In contrast, the dephenylation reaction of 2 with 1 or 2 equiv of CF3SO3H/iBu2AlH proceeded much less selectively and afforded the desired Ph/H-germasilanes Ph2HGeSi(SiH3)3 and PhH2GeSi(SiH3)3 along with considerable amounts of Si-Ge scission products.
- Stueger, Harald,Christopoulos, Viktor,Temmel, Andrea,Haas, Michael,Fischer, Roland,Torvisco, Ana,Wunnicke, Odo,Traut, Stephan,Martens, Susanne
-
p. 4034 - 4038
(2016/05/19)
-
- Hydrogermolysis reactions involving the α-germylated nitriles R3GeCH2CN (R = Ph, Pri, But) and germanium amides R3GeNMe2 (R = Pri, But) with Ph3GeH: Substituent-dependent reactivity and crystal structures of Pri3GeGePh3 and But3Ge[NHC...
-
Title full: Hydrogermolysis reactions involving the α-germylated nitriles R3GeCH2CN (R = Ph, Pri, But) and germanium amides R3GeNMe2 (R = Pri, But) with Ph3GeH: Substituent-dependent reactivity and crystal structures of Pri3GeGePh3 and But3Ge[NHC(CH3)CHCN]. The α-germylated nitriles R3GeCH2CN (R = Ph, Pri, But) and germanium amides R3GeNMe2 (R = Pri and But) have been prepared and characterized and their reactivity with Ph3GeH in CH3CN has been explored to investigate their utility for the construction of Ge-Ge bonds. In each case the phenyl and iso-propyl derivatives furnish the corresponding digermanes R3GeGePh3 (R = Ph, Pri) where the amide reagents are converted to R3GeCH2CN in situ which subsequently react with Ph3GeH. The rate of the Ge-C bond cleavage reactions was found to depend on the steric and electronic properties of the organic substituents. Attempted synthesis of But3GeGePh3 by these methods did not result in the desired product but rather in isolation of the 3-amidocrotononitrile species But3Ge[NHC(CH3)CHCN]. The crystal structures of Pri3GeGePh3 and But3Ge[NHC(CH3)CHCN] have been determined.
- Amadoruge, Monika L.,DiPasquale, Antonio G.,Rheingold, Arnold L.,Weinert, Charles S.
-
p. 1771 - 1778
(2008/09/18)
-
- Syntheses and characterization of organo-group 14 cobaloxime compounds
-
Reactions of cobaloxime Na[(t-BuPy)Co(DH)2] with Ph 3ECl (E = Si, Ge, Sn, and Pb) were investigated. Metal-metal bonded complexes (t-BuPy)Co(DH)2EPh3 were isolated for E = Sn and Pb. (f-BuPy)Co(DH)2SnPh3·(C2H 5)2O, C39H52CoN5O 5Sn, crystallized in the monoclinic space group P21/c (Z = 4) with unit cell dimensions a = 11.6443-(6) A, b = 15.6085(8) A, c = 22.6354(12) A, β = 96.634(1)°, and V= 4086.4(4) A3 at 295(2) K. The structure resembled those of six-coordinate alkyl cobaloxime complexes and had Co-NPy and Co-Sn distances of 2.056(2) and 2.5568(3) A, respectively. (t-BuPy)Co(DH) 2PbPh3, C35H42CoN5O 4Pb, crystallized in the monoclinic space group P21/n (Z = 4) with unit cell dimensions a = 15.0104(7) A, b = 15.7693(8) A, c = 16.6230(8) A, β = 114.348(1)°, and V = 3584.8(3) A3 at 295(2) K. The complex was nearly isostructural with the Sn analogue and had Co-NPy and Co-Pb distances of 2.049(2) and 2.6191(4) A, respectively. Coupling of the ortho phenyl protons to the spin 1/2 isotopes of Sn and of Pb was a characteristic feature of the 1H NMR spectrum. Additional, longer range couplings were observed for the Pb complex and for both complexes in the 13C NMR. Metal-metal bonded complexes were not obtained for E = Si or Ge. The products isolated in the latter case were the hydride Ph3GeH and the cobalt(II) complex (t-BuPy)Co(DH)2,C17H27CoN5O 4, which crystallized in the orthorhombic space group Pbcn (Z = 8). Unit cell dimensions were a = 17.9821(11) A, b = 9.7449(6) A, c = 22.7374(15) A, and V = 3984.4(4) A3 at 295(2) K. The five-coordinate complex had Co-NPy = 2.096(2) A and was dimeric in the lattice.
- Stolzenberg, Alan M.,Workman, Sarah R.,Gutshail, Jessica E.,Petersen, Jeffrey L.,Akhmedov, Novruz
-
p. 6744 - 6754
(2008/10/09)
-
- Preparation, structural characterization, and photochemical reactions of silyl- and germylborates
-
Silylborates (Li[PhnMe3-nSiBPh3], n = 1-3) and germylborates (Li[PhnMe3-nGeBPh3], n = 1-3; M[Et3- GeBPh3], M = Li, Na, K) were prepared by the reaction of the corresponding silyl- and germylalkali metals with triphenylborane in a hexane/benzene mixed solvent. The silyl- and germylborates were fully identified by 1H, 13C, 11B, and 7Li NMR spectroscopic methods. The solid-state structure of germylborates Li[Ph3GeBPh3] and M[Et3GeBPh 3] (M = Li and Na) were determined by X-ray diffraction analyses. The polymeric structure of M[Et3GeBPh3] was observed in the solid state and in hydrocarbon solution. The alkali metal atoms were located near the center of the benzene ring of triphenylborane and interacted with the neighboring borate molecules by Li+-π interaction. The polymeric structure was broken by the addition of MeOH. However, M[Et 3GeBPh3] was coordinated by three MeOH molecules to form a dimeric structure without methanolysis reaction. The primary processes in photochemical reactions of silyl- and germylborates were investigated by chemical trapping experiments and the CIDEP (chemical-induced dynamic electron polarization) method. The cleavage of the Ge-B (or Si-B) bonds of germylborates (or silylborates) was considered most probably to occur from their triplet states.
- Nanjo, Masato,Matsudo, Kazuhiko,Kurihara, Mari,Nakamura, Sayaka,Sakaguchi, Yoshio,Hayashi, Hisaharu,Mochida, Kunio
-
p. 832 - 838
(2008/10/09)
-
- Reaction of organoelement hydrides R3EH (E = Si, Ge) with metal tert-butylate (M = Al, Ti)-tert-butyl hydroperoxide oxidative systems
-
Trialkyl(aryl)silanes and -germanes effectively react with metal (Al, Ti) tert-butylate-tert-butyl-hydroperoxide under mild conditions (room temperature, benzene or tetrachloromethane) mainly by the element-hydrogen bond. The character of the products depends on the nature of the element, the structure of the radical bound to it, and the solvent. The process is radical in nature. It includes the stages of formation of element-centered radicals and their reaction with the oxygen generated by the system. The intermediate organometallic peroxides can also acts as oxidants for the element (Si, Ge)-hydrogen bonds. 2005 Pleiades Publishing, Inc.
- Stepovik,Gulenova,Martynova,Skvortsov,Cherkasov
-
p. 1098 - 1107
(2007/10/03)
-
- Reactivity of 2,6-diethyl-4,8-dimethyl-1,5-dioxo-s-hydrindacene towards radical, anionic and cationic germylation
-
The synthesis and diastereoisomeric resolution of 2,6-diethyl-4,8-dimethyl- 1,5-dioxo-s-hydrindacene allowed the determination of the structure of the meso compound by X-ray diffractometry. The diastereoisomers were inactive towards radical germylation but reacted with acidic hydrogermanes or germylithium yielding α-germylated alcohols. By contrast, they were poorly reactive towards germylamines or SET reactions. This diketone acts as an efficient spin trap in radical hydrogermylation of alkenes.
- El Kadib,Castel,Delpech,Rivière,Rivière-Baudet,Gornitzka,Aguirre,Manriquez,Chavez,Abril
-
p. 1256 - 1264
(2008/10/09)
-
- Reactivity of triphenylmethyl and triphenylgermyl derivatives of lanthanides
-
Reactions of bis(triphenylmethyl)ytterbium and bis(triphenylgermyl) ytterbium with mercuric chloride, triphenylbismuth, iodine, tert-butyl alcohol, phenylacetylene, and cyclopentadiene were studied. The higher reactivity of the former compound in these re
- Zhil'tsov,Makarov,Semkina
-
p. 1395 - 1397
(2007/10/03)
-
- Photochemistry of group 14 1,1,1-trimethyl-2,2,2-triphenyldimetallanes (Ph3MM′Me3; M, M′ = Si, Ge). Direct detection and characterization of silene and germene reactive intermediates
-
The photochemistry of trimethylsilyltriphenylgermane (Ph3GeSiMe3), triphenylsilyltrimethylgermane (Ph3SiGeMe3), and 1,1,1-trimethyl-2,2,2-triphenyldigermane (Ph3GeGeMe3) has been studied in hydrocarbon solution by steady state and laser flash photolysis methods and is compared to previously reported data for the homologous disilane Ph3SiSiMe3. A variety of products are formed upon photolysis of the three compounds in the presence of 2,3-dimethyl-1,3-butadiene or chloroform, but in each case the major ones are derived from M-M′ bond homolysis and dimethyl- or diphenylgermylene extrusion. The trapping products of the 1,3,5-(1-metalla)hexatriene derivatives formed by [1,3]-MMe3 migration into the ortho-position of one of the phenyl rings are formed as well, in yields of 9-30%. While these experiments indicate that germylenes are formed in at least twice the yield of the 1,3,5-(1-metalla)hexatrienes, only the latter and triphenylsilyl or triphenylgermyl radicals can be detected by laser flash photolysis techniques. The metallaenes have been identified on the basis of their time-resolved UV absorption spectra and absolute rate constants for reaction with 2,3-dimethylbutadiene, methanol, acetone, acetic acid, oxygen, and carbon tetrachloride and can be distinguished from germylenes by their lack of reactivity toward triethylsilane and chloroform. Radical formation is shown to result from reaction of the triplet states of these compounds, and a triplet lifetime is estimated for Ph3GeSiMe3 and compared to that of the disilane homologue. The results of time-resolved experiments on other, related compounds are discussed in light of these results.
- Leigh, William J.,Toltl, Nicholas P.,Apodaca, Paula,Castruita, Madeli,Pannell, Keith H.
-
p. 3232 - 3241
(2008/10/08)
-
- Etude du transfert monoelectronique entre des germylanions et des piegeurs de spin dia et paramagnetiques
-
Reactions between organogermyllithium R3GeLi and several substrates favoring SET reactions (3,5-di-t-butyl-orthoquinone, fluorenone, tetracyanoquinodimethane, 2,4,6-tri-t-butylnitrosobenzene, etc.) lead mainly to the formation of digermanes and O- or N-germyl adducts.All these reactions seem to proceed principally by single-electron transfer.An ESR study of the reaction shows transient organic radical anion formation and germanium-centred radicals R3Ge.The prepondancy of this mechanism can be demonstrated by the reaction between R3GeLi and a paramagnetic quinonic species, the galvinoxyl radical: the latter is almost completely transformed into a diamagnetic anion.Digermanes mainly produced in these reactions are formed via radicalar duplication as well as lithiogermolysis of reaction adducts.
- Riviere, P.,Castel, A.,Desor, D.,Abdennadher, C.
-
-
- ETUDE DE REACTIONS PAR TRANSFERT MONOELECTRONIQUE ENTRE DIVERS HYDROGERMANES A CARACTERE ACIDE ET DES SYSTEMES QUINONIQUES DIA- ET PARA-MAGNETIQUES
-
The chlorogermanes PhnCl3-nGe-H (n = 0, 1, 2) were treated with diamagnetic (3,5-di-t-butylorthoquinone) 1 and the paramagnetic galvinoxyl 2.These reactions occur mainly by monoelectron transfer giving the corresponding adducts.In the case of 3,5-di-t-butylorthoquinone, the resulting 1-4 adducts decompose by two simultaneous processes (HCl elimination and redistribution) yielding germadioxolanes.The chlorogermadioxolanes prepared in this way easily cause halogenic redistribution leading to chlorogermanes and germylcatecholates having branched or spiranestructure.In the case of the galvinoxyl radical, the same chlorogermanes lead by monoelectron transfer to the corresponding quinophenol and an intermediate germanium-centered radical.The latter by recombination outside the solvent cage, gives digermane.However, its primary reaction, which occurs within the solvent cage, is with quinophenol to form two isomeric O- and C-germylated catechols.The C-isomer is by far predominant as it also formed in the secondary hydrogermylation of quinophenol produced in the initial stage of the reaction.We have been able to confirm these mechanisms by a comparative study of the reaction of germanium hydrides R3Ge?+-H?-, acidic germanes X3Ge?--H?+, and germanates X3Ge(-)N-H(+) with galvinoxyl and the corresponding quinophenol.Key words: SET reactions; germylations; quinones; chlorohydrogermanes; chlorogermanes; chlorogermanates.
- Riviere, P.,Castel, A.,Abdennadher, C.
-
p. 181 - 194
(2007/10/02)
-
- Synthesis, characterization, and reactivity of triphenylsilyl, triphenylgermyl, and triphenylstannyl derivatives of zirconium and hafnium
-
The crystalline lithium silyl compound (THF)3LiSiPh3 (1) was isolated from the reaction of Ph3SiSiPh3 with lithium in tetrahydrofuran. This compound and tetrahydrofuran solutions of LiEPh3 (E = Ge, Sn
- Woo, Hee-Gweon,Freeman, William P.,Don Tilley
-
p. 2198 - 2205
(2008/10/08)
-
- Photochemical Reactions of Aryl-Substituted Digermanes through a Pair of Organogermyl Radicals
-
The photochemical reactions of aryl-substituted digermanes were investigated by trapping experiments and a laser flash photolysis technique.The photolysis of phenylated digermanes resulted in germanium-germanium bond homolysis to give a pair of two germyl radicals.The germyl radicals abstracted a chlorine atom from carbon tetrachloride to give chlorogermanes.The pair of germyl radicals also underwent ipso-substitution, which was a precursor of the germylenes.The mechanism for the photochemistry of phenylated digermenes is discussed.
- Mochida, Kunio,Wakasa, Masanobu,Sakaguchi, Yoshio,Hayashi, Hisaharu
-
p. 1889 - 1895
(2007/10/02)
-
- The Ge-H bond dissociation energies of organogermanes. A laser-induced photoacoustic study
-
The Ge-H bond dissociation energies (BDE's) of several alkyl- and aryl-substituted germanium hydrides have been measured in hydrocarbon solution at room temperature by a photoacoustic technique. The BDE's of these hydrides are unaffected by alkyl substitution when compared to those for GeH4 and are in the range of 81.6-82.6 kcal/mol. Aryl substitution leads to a slightly weakened Ge-H bond (79.2-80.2 kcal/mol) in the cases of phenyl-, diphenyl-, and triphenylgermane. In an effort to further characterize the formation, spectral and decay properties of the germyl radicals some laser flash photolysis studies were carried out. The rate constants for hydrogen abstraction by tert-butoxy radicals were determined by nanosecond laser flash photolysis and fell in the range (0.7-4.4) × 108 M-1 s-1. The aryl-substituted germyl radicals add to the aromatic rings of the germane precursor. Diphenylgermyl radical adds to diphenylgermane with a rate constant of 2.9 × 105 M-1 s-1, while phenylgermyl radical adds to phenylgermane with a rate constant of 1.2 × 106 M-1 s-1.
- Clark, K. Brady,Griller, David
-
p. 746 - 750
(2008/10/08)
-
- Reactivity of dianionic hexacoordinate germanium complexes toward organometallic reagents. A new route to organogermanes
-
Lithium and potassium tris(benzene-1,2-diolato)germanates (2a and 2b, respectively) and potassium tris(butane-2,3-diolato)germanate (3) are easily prepared from GeO2 in quantitative yields. They are very reactive toward organometallic reagents, the reactivity depending on the ligands on the germanium. Complexes 2 react with an excess of Grignard reagent to give the corresponding tetraorganogermanes R4Ge while the less reactive complex 3 leads to the functional triorganogermanes R3GeX. Tetraorganogermanes can also be prepared from complex 2b by reaction with organic bromides in the presence of Mg (Barbier reaction). The influence of Cp2TiCl2 and MgBr2 on the reactivity of Grignard reagents with these complexes was also investigated: in both cases formation of triorganogermanes was favored.
- Cerveau,Chuit,Corriu,Reyé
-
p. 1510 - 1515
(2008/10/08)
-
- Etude de la reaction de germyllithiums sur la di-t-butyl-3,5 orthoquinone: mise en evidence d'un mecanisme par transfert monoelectronique
-
Reactions between organogermyllithiums R3GeLi and 3,5-di-t-butylorthoquinone mainly give digermanes but also O-germylcatechol and germadioxolanes.It appears that these reactions start after an initial single electron transfer (SET) which is supported by a
- Riviere, P.,Castel, A.,Ko, Y. H.,Desor, D.
-
p. 147 - 156
(2007/10/02)
-
- Tri(η-cyclopentadienyl)uranium(IV) Silyl and Siloxide Compounds. Crystal Structure of 5-C5H5)3(OSiPh3)>. Insertion of Isocyanide into a Uranium-Silicon Bond
-
The complex 5-C5H5)3(SiPh3)> (1) has been synthesized from 5-C5H5)Cl> and Li(SiPh3) and fully characterized.The direct U-Si bond in (1) is quite reactive towards proton acidic molecules, moreover it reacts with 2,6-dimethylphenyl iscyanide to give the insertion product 5-C5H5)3(C(NC6H3Me2-2,6)SiPh3)> (3), the (1)H n.m.r. and i.r. data for which show that the isocyanide ligand is η2-co-ordinated to the uranium atom.The synthesis of 5-C5H5)3(OSiPh3)> (2) by reaction of 5-C5H5)3(NEt2)> with SiPh3(OH) and its X-ray structural determination are also reported.Compound (2) crystallizes from diethyl ether in the monoclinic space group P21/n with a=15.368(5), b=17.333(5), c=10.778(5) Angstroem, and β=106.27(3) deg for Z=4.The main features are the almost linear U-O-Si bond angle of 172.6(6) deg and the short U-O distance of 2.135(8) Angstroem.
- Porchia, Maria,Brianese, Nicola,Casellato, Umberto,Ossola, Franco,Rossetto, Gilberto,at al.
-
p. 677 - 682
(2007/10/02)
-
- Untersuchungen von Diiodogermylen und Triphenylphosphindiiodogermylen und die Kristallstruktur von Triphenylphosphindiiodogermylen
-
Reaktivitaeten und chemische Eigenschaften von Diiodogermylen und Triphenylphosphindiiodogermylen wurden durch ihre Reaktionen mit Organolithium-Verbindungen oder Butadienen untersucht.Die Kristallstruktur von Triphenylphosphindiiodogermylen wurde roentgenographisch aufgeklaert.
- Inoguchi, Yoshio,Okui, Shuko,Mochida, Kunio,Itai, Akiko
-
p. 974 - 977
(2007/10/02)
-
- OXIDATIVE-REDUCTIVE TRANSMETALLATION REACTIONS OF GERMYLMERCURY COMPOUNDS WITH BIS(ETHYLBENZENE)VANADIUM AND VANADOCENE
-
The ionic complexHg>-+ has been obtained in the reaction of 2Hg with bis(ethylbenzene)vanadium.Dicyclopentadienylvanadium displaces mercury in 2Hg to give the covalent product Cp2VGe(C
- Bochkarev, M. N.,Pankratov, L. V.,Cherkasov, V. K.,Razuvaev, G. A.,Latyaeva, V. N.,Lineva, A. N.
-
-
- Stereochemistry of the insertion of manganese into Si-H and Ge-H bonds. Complexes containing a two-electron, three-center Mn?H?Si (or Ge) interaction
-
A crystallographic study of the complex (-)-(η5-CH3C5H4)(CO) 2(1-NpPhMeSi)(H)Mn (1,1-Np = 1-C10H7, Ph = C6H5, Me = CH3) reveals that the oxidative addition of (+)-1-NpPhMeSiH on methylcymantrene takes place with retention of configuration at silicon. The gennyl complexes (η5CH3C5H4)(CO) 2(R3Ge)(H)Mn are prepared either by oxidative addition of R3GeH (R = Ph) on (η5-CH3C5H4)(CO)3Mn or by protonation of the related anions [(η5-CH3C5H4)(CO) 2(R3Ge)Mn]- (R3 = Ph3, 1-NpPhMe, Cl3). Only the cis isomers are obtained. Complex 2 (R = Ph) exhibits a higher acidity than the silyl analogue. This acidity is close to that of HCl. However both 1 and 2 undergo easy elimination of R3SiH or R3GeH when treated with PPh3. The Mn-Ge bond is cleaved by H2O, CH3OH, Cl2, and CCl4; this behavior contrasts with that of 1 since Cl2 or CCl4 lead to elimination. These observations are in agreement with a two-electron, three-center bond between manganese, silicon (or germanium), and hydrogen.
- Carré, Francis,Colomer, Ernesto,Corriu, Robert J. P.,Vioux, André
-
p. 1272 - 1278
(2008/10/08)
-
- POLYGERMANES PRECURSEURS D'ESPECES DU GERMANIUM A COORDINNANCE NON USUELLE
-
Several thermal or photochemical α-elimination reactions of functional polygermanes lead to germylenes, R2Ge.Photolysis of polygermanes, cyclopolygermanes and polygermylmercury compounds and also hydrogen abstraction from various organohydropolygermanes using t-BuO., lead to the formation of polymetallated chains containing one or two germanium-centered radicals.These polygermyl radicals give germylenes, R2Ge, germanium centered radicals Ge., α-digermyl diradicals (or digermenes) Ge.-Ge. or Ge=Ge> and β- or γ-polygermyl diradicals via ahomolytic monoelectronic α-elimination process.In some cases the formation of α-digermyl diradicals or digermenes can also be seen as occuring through dimerization of germylenes but with lower yields.All these intermediates have been characterized by several trapping reactions with dimethyl disulfide, 2,3-dimethylbutadiene or biacetyl.
- Riviere, P.,Castel, A.,Satge, J.,Guyot, D.
-
p. 193 - 206
(2007/10/02)
-
- METHYLPHENYLTRIPHENYLGERMYLSILANES FONCTIONNELS OPTIQUEMENT ACTIFS. II. REACTIONS DE CLIVAGE DE LA LIAISON Si-Ge
-
The cleavage of a silicon-germanium bond in the presence of organometallics has been studied on the optically active compounds MePh(X)SiGePh3 (X=H, OMe).Depending on the nature of the nucleophile, we obtained mixed products, corresponding to the formation of Ph3Ge-, transient radical-anions, or catalytic reactions.
- Corriu, R. J. P.,Ould-Kada, S.,Lanneau, G. F.
-
-
- METHYLPHENYLTRIPHENYLGERMYLSILANES FONCTIONNELS OPTIQUEMENT ACTIFS
-
The structure of the unsymmetric compound MePh(X)SiGePh3 (X=H, F, Cl, OR) has been resolved.The stereochemistry of nucleophilic substitutions at silicon is not changed with Ph3Ge as substituent.Stereochemical correlations allow the determination of absolute configurations.
- Corriu, R. J. P.,Ould-Kada, S.,Lanneau, G.
-
-
- CLEAVAGE OF SILICON- AND GERMANIUM-TRANSITION METAL BONDS. DEPENDENCE OF THE STEREOCHEMISTRY ON THE NATURE OF THE LIGANDS AND THE GEOMETRY OF COMPLEXES
-
The cleavages of some new optically active complexes containing Co-Si (or -Ge), Mn-Si (or -Ge), Re-Ge and W-Ge bonds are described.Electrophiles cleave the Co-Si bond with good retention of configuration at silicon, while the Mn-Si bond is not cleaved und
- Cerveau, Genevieve,Colomer, Ernesto,Corriu, Robert J. P.
-
-
- THE MECHANISM OF CLEAVAGE OF Si-Ge BONDS BY BASE
-
The compounds R3SiGePh3 with R = Me or Et have been shown to undergo cleavage in NaOMe-MeOH to give Ph3GeH.From rate measurements and solvent isotope effect studies it is concluded that the Ph3Ge- anion separates in the rate-determining transit
- Eaborn, Colin,Mahmoud, Foad M.S.
-
-
- THE CHEMICAL BEHAVIOUR OF COBALT-STABILIZED-CARBENES HAVING A TRISUBSTITUTED SILYL OR GERMYL LIGAND. STEREOSPECIFIC FORMATION OF BENZOYLSILANES FROM THE REACTION OF ORGANOSILYL-COBALT TETRACARBONYL DERIVATIVES WITH PHENYLLITHIUM
-
We report the chemical behaviour of cobalt-stabilized carbenes, R3M(CO)3CoC(OEt)R', and their parent anions, R3M(CO)3CoC(O-)R', where M = Si or Ge.The anions where M = Si, R' = Ph decompose thermally into the corresponding benzoylsilanes; when the silicon atom is chiral (R3 = MePh-1-Np) optically active R3SiCOPh is obtained with complete retention of configuration.
- Cerveau, Genevieve,Colomer, Ernesto,Corriu, Robert J.P.,Young, J. Colin
-
-
- ELECTROCHEMICAL REDUCTION OF TRIORGANOHALO-SILANES AND -GERMANES
-
The electrochemical reduction of triorganohalo-silanes and -germanes in 1,2-dimethoxyethane has been investigated by polarography, cyclic voltammetry, controlled potential coulometry, and macroscale electrolysis.The reduction of the silicon compounds exhibits a single irreversible wave.The polarograms for the germanium compounds exhibit two irreversible waves.The second wave shifts to more anodic potentials with addition of phenol or acetic acid.Dimer (i.e. disilanes or digermanes) are the main product of macroscale electrolysis in aprotic solvent but the hydrides are the principal products in protic solution.The results are interpreted in terms of the coexistence of two separate processes.The first involves a one electron reduction followed by dimerization of the radical.At higher cathodic potential a two electron charge transfer step occurs to form an anion, which in aprotic solvents reacts with the starting halogeno compound to form dimer, and in protic solutions gives the hydride.
- Corriu, R. J. P.,Dabosi, G.,Martineau, M.
-
-
