- Oligogermanes containing only electron-withdrawing substituents: Synthesis and properties
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A series of germanes Ar3GeX, containing electron-withdrawing substituents [Ar = p-FC6H4, 1a-d, 1a (X = Cl), 1b (X = Br), 1c (X = H), 1d (X = NMe2); p-F3CC6H4, 2a-d, 2a (X = Cl), 2b (X = Br), 2c (X = H), 2d (X = NMe2)], was synthesized and used to prepare symmetrical digermanes Ar3Ge-GeAr3, (p-FC6H4)3GeGe(C6H4F-p)3 (3), and (p-F3CC6H4)3GeGe(C6H4CF3-p)3 (4) and trigermane [(pF3CC6H4)3Ge]2Ge(C6F5)2 (5) by hydrogermolysis reaction. The properties of all compounds were investigated by multinuclear NMR and for oligogermanes by UV/vis and fluorescence spectroscopy, as well as by electrochemical methods. In addition, the molecular structures of 1a, 1b, 2b, 2c, and 3-5 were studied by X-ray diffraction analysis. Compound 5 showed a significantly shifted UV/visible absorption to the red field in comparison with previously described derivatives.
- Zaitsev, Kirill V.,Lam, Kevin,Zhanabil, Zhaisan,Suleimen, Yerlan,Kharcheva, Anastasia V.,Tafeenko, Viktor A.,Oprunenko, Yuri F.,Poleshchuk, Oleg Kh,Lermontova, Elmira Kh,Churakov, Andrei V.
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p. 298 - 309
(2017/04/01)
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- A computational study of the fluctional behaviour of group 14 substituted ortho -semiquinone radicals
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The dynamics of the 1,4-migration of some O-substituted 3,5-di-tert-butyl-ortho-semiquinone radicals have been calculated by density-functional theory (DFT). There is very good agreement in the rate constant and Arrhenius parameters between these calculations and experimental values for migration of H, D, and the Me3Si group. For the Me 3Sn group, the calculations indicate an incredibly fast migration (k293K = 2.0 × 1012 s-1), a result that is consistent with experimental data (k293K > 109 s-1). Other O-substituents examined by DFT and compared with experimental data were H3C and Me2ClSn.
- Ingold,Dilabio, Gino A.
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p. 235 - 240
(2011/04/23)
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- Reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride
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The effect of substituents at the silicon and germanium atoms in reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride was studied. The only occurring process is the exchange of the chlorine atoms at Ge for the phenyl groups from Si; an increase in the number of methyl groups or chlorine atoms at Si promotes formation of phenyltrichlorogermane, and an increase in the number of phenyl groups or replacement of the chlorine atom at the Si atom by hydrogen leads to the formation of di-and triphenylchlorogermanes. Neither phenyl nor other radicals are transferred back from Ge to Si in the course of reactions of phenylgermanes with methylchlorosilanes in the presence of aluminum chloride; the only occurring processes are the exchange of the phenyl or methyl radicals bonded to Ge for the Cl atom bonded to Al and the disproportionation of phenylchlorogermanes. Nauka/Interperiodica 2006.
- Zhun,Sbitneva,Polivanov,Chernyshev
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p. 1564 - 1570
(2008/02/09)
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- Reaction of germanium tetrachloride with chloro(phenyl)silanes in the presence of aluminum chloride
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The effect of the quantity of aluminum chloride on the direction and depth of reaction of germanium tetrachloride with chloro(phenyl)silanes of the general formula PhnSiCl4-n (n = 1 - 3) was studied to show that radical exchange between germanium and silicon is initiated only if the mixture contains no less than 2.5-5 wt % of aluminum chloride. With trichloro(phenyl)silane, the radical exchange is initiated at 5 wt % of aluminum chloride and results in exclusive formation of trichloro(phenyl)germane. The reactions of GeCl4 with dichlorodiphenylsilane and chlorotriphenylsilane in the presence of 2.5-7.5 wt % of aluminum chloride give dichlorodiphenylgermane as the major product, and at AlCl3 concentrations of above 10 wt % the major product becomes to be trichloro(phenyl)germane.
- Zhun',Sbitneva,Chernyshev
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p. 867 - 869
(2007/10/03)
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- Selective synthesis of chlorohydrogermanes from mono-, di-, and trihydrogermanes
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Treatment of hydrogermanes, R4-nGeHn (R = Hex, Et, Ph, n = 1-3), with 2 equiv of CuCl2 in ether at room temperature or in toluene under reflux led to selective replacement of an H-Ge bond with a Cl-Ge bond, giving the corresponding chlorohydrogermanes, R4-nGeHn-1Cl, selectively.
- Ohshita, Joji,Toyoshima, Yutaka,Iwata, Arihiro,Tang, Heqing,Kunai, Atsutaka
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p. 886 - 887
(2007/10/03)
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- Phenyltrichlorogermane synthesis by the reaction of chlorobenzene and the dichlorogermylene intermediate formed from elemental germanium and tetrachlorogermane
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Phenyltrichlorogermane was synthesized with high selectivity, 96%, from elemental germanium, tetrachlorogermane, and chlorobenzene using no catalyst, almost all germanium and tetrachlorogermane being converted. Dichlorogermylene was formed as a reaction intermediate by the reaction of germanium with tetrachlorogermane and inserted into the C-Cl bond of chlorobenzene to yield phenyltrichlorogermane.
- Okamoto, Masaki,Asano, Takuya,Suzuki, Eiichi
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p. 5583 - 5585
(2008/10/08)
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- Microwave-assisted Lewis acid catalysis: Application to the synthesis of alkyl- or arylhalogermanes
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Under microwave irradiation, alkyl- or arylhalogermanes RnGeX4-n (R = Et, Bu, Ph; X = Cl, Br) are obtained by redistribution reactions of R4Ge with GeX4. These experimental conditions permit the synthesis of such compounds in good yield in a few minutes at atmospheric pressure. The direct Friedel-Crafts germylation of benzene and toluene by germanium tetrachloride also has been performed, but yields were low.
- Laurent, Régis,Laporterie, André,Dubac, Jacques,Berlan, Jacques
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p. 2493 - 2495
(2008/10/08)
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- BIS-ORGANOMETAL-AMINES-α-HALOGENOGERMANIEES
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Polychlorogermanes RCl2Ge-N(SiMe3)2, where R = Cl or N(SiMe3)2, have been synthesized by the reaction of germanium tetrachloride with bis(trimethylsilyl)amine or the corresponding N-lithium derivative.Similarly, diaryldihalogermanes gave in high yield diarylhalogenogermanes Ar2(X)Ge-N(MMe3)2, where X = Cl or F; Ar = Ph or Mes; M = Si, Ge.From these compounds elimination of Me3GeCl is easier than elimination of Me3SiCl.However, halogermane or silane eliminations occur only at high temperature (150-200 deg C) in competition with redistribution reactions by Ge-Cl/Ge-N exchange.Under these conditions, only the formation of germazanes or silagermazanes, i.e., germa-imine oligomers, could be observed.The polyhalogenated compounds may be used as precursors for ceramics. Key words: Bis(trimethylsilyl)aminodiorganohalogermanes; bis(trimethylgermanylamino)diorganochlorogermane; N-polyhalogenogermyl-N,N-bis(trimethylsilyl)amines, precursors for ceramics.
- Riviere-Baudet, Monique,Khallaayoun, Abdelhay,Ahra, Mohamed
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- ETUDE DE REACTIONS PAR TRANSFERT MONOELECTRONIQUE ENTRE DIVERS HYDROGERMANES A CARACTERE ACIDE ET DES SYSTEMES QUINONIQUES DIA- ET PARA-MAGNETIQUES
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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.
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p. 181 - 194
(2007/10/02)
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- Photochemistry of aryl-substituted trigermanes. Generation and mechanism of formation of germylenes
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Photochemical reactions of aryl-substituted trigermanes have studied by trapping experiments, matrix isolation, and laser flash-photolysis techniques.Photolysis of the phenylated trigermanes involved both the simple extrusion of germylenes and the formati
- Mochida, Kunio,Yoneda, Isao,Wakasa, Masanobu
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- Addition 1,4 de divers organo- et organohalogeno-hydrogermanes sur la di-t-butyl-3,5 orthoquinone
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The thermal 1,4-addition of triorganohydrogermanes R3GeH(R=Et, Ph) with 3,5-di-t-butylorthoquinone leads to their corresponding mono-O-germylated catechols in good yields.Similarly, the organohalohydrogermanes give the 2,2-di-organo- (or 2,2-organohalo)(6,8-di-t-butyl)-4,5-benzo-2-germa-1,3-dioxolanes after dehydrochlorination of transient mono-O-chlorogermylated catechols.Since these reactions are only slightly dependent on solvent and radical initiators, the mechanism probably involves monoelectronic transfer with the formation of a radical anion pair in the first step.The ESR measurements show the transient formation of a paramagnetico-semiquinonic species which supports the proposed mechanism.
- Riviere, P.,Castel, A.,Satge, J.,Guyot, D.,Ko, Y. H.
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- Preliminary communication. Kinetic spectroscopy of diphenylgermylene Ph2Ge following laser flash photolysis of bis(trimethylsilyl)diphenylgermane (Me3Si)2GePh2
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A transient, λmax 445 nm, was observed in the 266 nm laser flash photolysis of cyclohexane solutions of (Me3Si)2GePh2, and rate constants were recorded for its disappearance in the presence of various trapping agents.The reactivity profile is in accord with the identification of the carrier as diphenylgermylene Ph2Ge, that dimerizes to tetraphenyldigermene Ph2Ge=GePh2, λ7max3 320 nm.
- Konieczny, Stanislaw,Jacobs, S. Joshua,Wilking, Janet K. Braddock,Gaspar, Peter Paul
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p. C17 - C22
(2007/10/02)
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- On Polygermanes, XVIII. Synthesis of the Multifunctional Digermanes Ph6-nGe2Cln (n = 2, 3, 4) and of Ph2GeCl2 under Pressure
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Reaction of Ph6Ge2 with liquid HCl under pressure leads to di-, tri- and tetrachloro phenyldigermanes.The yield of higher chlorinated products increases with increasing pressure.The analogous reaction of Ph4Ge yields Ph2GeCl2 quantitatively.The Ge-Ge bond is most unstable in the case of Ph3Ge2Cl3 both chemically and thermally.The crystal structure of Ph2Ge2Cl4 has been determined (R = 0.057), Ge-Ge 241.3(1) pm. - Keywords: Functional Digermanes, Synthesis, Structure
- Haeberle, Karl,Draeger, Martin
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p. 323 - 329
(2007/10/02)
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- Cycloaddition of Germylenes to 3,5-Di-t-butylorthoquinone
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The germylenes X2Ge, RGeX and R2Ge (X= halogen, OR; R= alkyl or aryl) react at room temperature with 3,5-di-t-butyl orthoquinone by regioselective cycloaddition.The corresponding substituted 2-germa-1,3-dioxolans are formed similarly in good yields, but t
- Riviere, Pierre,Castel, Annie,Satge, Jacques,Guyot, Daniel
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p. 157 - 164
(2007/10/02)
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- DIOXA- ET DITHIAGERMOLES: SYNTHESE ET QUELQUES ASPECTS DE LEUR REACTIVITE
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Synthetic methods to obtain new dioxagermoles and dithiagermoles are described.Dioxagermoles decompose to germylenes and α-diketone on thermolysis, and formation of cyclotrigermathianes (R2GeS)3 from dithiagermoles is observed at about 200 deg C via a R2Ge=S intermediate.Exchange reactions between dioxagermoles or dithiagermoles and thiophosgene give a dioxolethione and a dithiolethione, respectively.In the exchange reaction between dithia- and dioxa-germoles with GeCl2*dioxane, formation of new stable unsaturated germylenes is observed.
- Lavayssiere, Helene,Dousse, Gabriel
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p. C17 - C22
(2007/10/02)
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- POLYGERMANES PRECURSEURS D'ESPECES DU GERMANIUM A COORDINNANCE NON USUELLE
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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.
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p. 193 - 206
(2007/10/02)
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- 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
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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
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- SYNTHESE DE COMPOSES A LIAISON MIVB-MERCURE. PRECURSEURS D'ESPECES MONOVALENTES (GERMYNES), ET BIVALENTES (GERMYLENES), DE RADICAUX CENTROMETALLES ET D'INTERMEDIAIRES
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Polynuclear germyl-mercury compounds are obtained from the reaction of organohydrogermanes PhnGeH4-n or digermanes Ph2nGe2H4-n (n = 1, 2) with dialkylmercury R2Hg.Di- or tri-mercurated geminal polygermates thus synthesized generally present a low stability and undergo thermal- or photodecompositions leading to the corresponding monovalent (germynes), divalent (germylenes) or, trivalent (germanium centered radicals) species and also to intermediate biradicals which could be considered as limit forms of germanium doubly-bonded compounds .Such intermediates have been chemically and spectroscopically characterized.Extension of these reactions to the silicon analogs met with difficulties, and thus previously observed differences between silicon and germanium chemistry were confirmed.
- Riviere, P.,Castel, A.,Satge, J.
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p. 351 - 367
(2007/10/02)
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