- Organometallic compounds of the lanthanides. 64. Synthesis and X-ray crystal structures of dimethylgermyl bis(tetramethylcyclopentadienyl) halide and alkyl derivatives of the lanthanides
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Metathesis of Me2GeCl2 or Me2SnCl2 with 2 equiv of LiC5Me4H affords Me2Ge(C5Me4H)2 (1) and Me2Sn(C5Me4H)2 (2), respectively. The subsequent deprotonation of 1 with MeLi yields only the desired dilithium salt Me2Ge(C5Me4Li)2 (3) whereas 2 forms Me4Sn and two LiC5Me4H. The trichlorides of neodymium, samarium, holmium, and lutetium react with the dilithium salt 3 with the formation of Me2Ge(C5Me4)2LnCl 2Li(THF)2 (Ln = Nd (4), Sm (5), Ho (6), Lu (7)). The reaction of 4 and 6 with LiCH(SiMe3)2 produces Me2Ge(C5Me4)2LnCH(SiMe 3)2 (Ln = Nd (8), Ho (9)). The new compounds have been characterized by elemental analysis, mass and NMR spectra, as well as X-ray structural analysis of 5, 7, and 9. The halides 5 and 7 crystallize in the monoclinic space group P21/c (No. 14) with a = 9.7284 (9), b = 19.397 (1), c = 16.610 (2) ?, β = 98.963 (9)°; Z = 4 or a = 9.578 (3), b = 19.218 (4), c = 16.525 (4) ?, β = 99.73 (2)°; Z = 4, respectively. Least-squares refinement led to a final R value of 0.020 (Fo > 4σ(Fo)) for 5554 independent reflections for 5 or of 0.028 (Fo > 3σ(Fo)) for 5822 independent reflections for 7. Compound 9 crystallizes in the monoclinic space group P21/m (No. 11) with a = 9.2621 (8), b = 14.216 (2), c = 11.839 (2) ?, β = 107.79 (1)°, Z = 2, and R = 0.023 (Fo > 4σ(Fo)) for 2954 reflections. The structure of 9 shows a short Ho-C (methyl) contact of 2.774 (4) ?.
- Schumann, Herbert,Esser, Lothar,Loebel, J?rg,Dietrich, Andreas,Van Der Helm, Dick,Ji, Xinhua
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- Molecular Oligogermanes and Related Compounds: Structure, Optical and Semiconductor Properties
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The optical (UV/Vis absorbance, fluorescence in the solid state and in solution) and semiconducting properties of a number of di- and trigermanes as well as related silicon- and tin-containing germanes, 1–6 ((p-Tol)3GeGeMe3 (1), Ph3SnGe(SiMe3)3 (2), (C6F5)3GeGePh3 (3), (p-Tol)3GeSiMe2SiMe3 (4), (p-Tol)3GeGeMe2Ge(p-Tol)3 (5), (p-Tol)3GeSiMe2SiMe2Ge(p-Tol)3 (6)) were investigated. Molecular structures of 5 and 6 were studied by X-ray diffraction analysis. All compounds displayed luminescence properties. In addition, a band gap (of about 3.3 eV) was measured for compounds 1–6 showing that those molecules display semiconductor properties.
- Zaitsev, Kirill V.,Tafeenko, Viktor A.,Oprunenko, Yuri F.,Kharcheva, Anastasia V.,Zhanabil, Zhaisan,Suleimen, Yerlan,Lam, Kevin,Zaitsev, Vladimir B.,Zaitseva, Anna V.,Zaitseva, Galina S.,Karlov, Sergey S.
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- Transient and Matrix Ultraviolet Absorption Spectra of Dimethylgermylene (Dimethylgermanediyl)
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Dimethylgermylene (1), generated from a new precursor dimethylbis(phenylseleno)germane (2), has been observed as a transient species by time-resolved laser flash photolysis at room temperature.
- Tomoda, Shuji,Shimoda, Masakatsu,Takeuchi, Yoshito,Kajii, Yoshizumi,Obi, Kinichi,et al.
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- Reactivity, absorption and emission of dimethylgermylene photo-generated from dodecamethylcyclohexagermane
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The UV photolysis of dodecamethylcyclohexagermane (1) in cyclohexane at room temperature proceeds readily with loss of dimethylgermylene species to give two of the lower homologs, decamethylcyclopentagermane (2) and octamethylcyclotetragermane (3).The photochemically generated dimethylgermylene species reacts with 2,3-dimethylbuta-1.3-diene or CCl4 to give 1,1,3,4,-tetramethyl-1-germacyclopent-3-ene or trichloromethyldimethylchlorogermane, respectiively.The transient absorption of 1 in cyclohexane at 450 nm obtained by laser flash-photolysis is due to dimethylgermylene.The reaction rates of dimethylgermylene with some substances are examined.In 3-methylpentane glass dimethylgermylene shows an absorption band at 430 nm and a fluorescence peak at 650 nm.The photo-generated germylene appears to be the singlet ground state.
- Mochida, Kunio,Kanno, Naoko,Kato, Ryuji,Kotani, Masahiro,Yamauchi, Seigo,et al.
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- 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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- Fast kinetic studies of the reactivities of transient germylenes in methanol and tetrahydrofuran solution
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Laser flash photolysis techniques have been employed to study the reactivities of dimethylgermylene (GeMe2), diphenylgermylene (GePh2), and a series of ring-substituted diarylgermylenes (GeAr 2) in methanol (MeOH) and tetr
- Lollmahomed, Farahnaz,Huck, Lawrence A.,Harrington, Cameron R.,Chitnis, Saurabh S.,Leigh, William J.
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p. 1484 - 1494
(2009/07/18)
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- Organotrichlorogermane synthesis by the reaction of elemental germanium, tetrachlorogermane and organic chloride via dichlorogermylene intermediate
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Organotrichlorogermanes were synthesized by the reaction of elemental germanium, tetrachlorogermane and organic chlorides, methyl, propyl, isopropyl and allyl chlorides. Dichlorogermylene formed by the reaction of elemental germanium with tetrachlorogermane was the reaction intermediate, which was inserted into the carbon-chlorine bond of the organic chloride to give organotrichlorogermane. When isopropyl or allyl chloride was used as an organic chloride, organotrichlorogermane was formed also in the absence of tetrachlorogermane. These chlorides were converted to hydrogen chloride, which subsequently reacted with elemental germanium to give the dichlorogermylene intermediate. The reaction of elemental germanium, tetrachlorogermane and organic chlorides provides a simple and easy method for synthesizing organotrichlorogermanes, and all the raw materials are easily available.
- Okamoto, Masaki,Asano, Takuya,Suzuki, Eiichi
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p. 2372 - 2376
(2007/10/03)
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- Studies of photochemical reactions of 7,8-digermabicyclo[2.2.2]octadienes by steady-state and laser flash photolysis techniques
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The photochemistry of 1,4-diphenyl-2,3-benzo-7,7,8,8-tetraalkyl-7, 8-digermabicyclo[2.2.2]-octadienes in solution has been studied in detail by steady-state, nanosecond laser flash photolysis, and matrix isolation techniques. Photolysis of 7,8-digermabicy
- Mochida, Kunio,Kayamori, Takanari,Wakasa, Masanobu,Hayashi, Hisaharu,Egorov, Mikhail P.
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p. 3379 - 3386
(2008/10/08)
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- Digermylplatinum(II) organometallic rings L2PtGe(Me2)EGeMe2 [E = N-, O, S, (η-C5H4)2Fe]
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The synthesis, reactivity, and characterization of the digermylplatinum(II) linear complexes (ClMe2Ge)2Pt(PPh3)2 (1) and (ClMe2Ge)2Pt(diphos) (2) and cyclic complexes (diphos)PtGe-(Me2)EGeMe2 [E = S (3), -NPh (4), (η5-C5H4)Fe(η5-C 5H4) (5), O (6)] are reported. The chemistry of 2-6 is illustrated through their reactions with phenylacetylene and N-methyltriazolinedione. Complexes 3 and 6 give double germylation of these unsaturated systems, while 2, by reaction with triazolinedione, gives the monogermylated complex Me2-(Cl)GePt(Cl)diphos and the dimer of the germylated heterocycle Me2GeNC(O)N(Me)C(O)N.
- Barrau,Rima,Cassano,Satgé
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p. 5700 - 5703
(2008/10/09)
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- Study of Photochemical Reactions of Decamethylcyclopentagermane
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The photolysis of decamethylcyclopentagermane (1) in cyclohexane at room temperature proceeds readily along with the generation of dimethylgermylene to give octamethylcyclotetragermane.Photochemically generated dimethylgermylene reacts with 2,3-dimethylbu
- Mochida, Kunio,Tokura, Satoshi
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p. 1642 - 1647
(2007/10/02)
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- Photochemical reactions of aryl-substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge). Formation of a radical pair
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Photochemical reactions of phenyl substituted catenates of group 4B elements, PhMe2E-E'Me3 (E, E' = Si and Ge) have been investigated by chemical trapping experiments and laser flash-photolysis.On irradiation, the phenylated group 4B catenate undergoes E-E' bond homolysis to give a pair of radicals (PhMe2E. and Me3E'.).In CCl4, these radicals are converted to the corresponding chlorides by abstraction of a chlorine atom.In a nonhalogenated solvent, the radical pair couples at the ipso-position of the phenyl group of the pairing radical (PhMe2E.) to yield the cor responding diradical.This undergoes either elimination of a divalent species (Me2E:) with concomitant formation of trimethylphenyl group 4B element PhMe3E') or intramolecular 1,2-group 4B element migration to yield group 4B metal-carbon double bonded species.The radical escapes from the solvent cage coupled to the metal atom of the radical to yield the dimetallic product.The reaction path observed is highly dependent on the nature of the group 4B element comprising the phenyl substituted catenate.
- Mochida, Kunio,Kikkawa, Haruhiko,Nakadaira, Yasuhiro
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- Palladium-Catalyzed Germylation of Organic Halides with a Digermane. Unexpected Formation of Germylene-Insertion Type Products
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Organic halides (RX) underwent dehalogenative germylation and germylene insertion type reactions with ClMe2GeGeMe2Cl in the presence of Pd(PPh3)4 as catalyst to give RGeMe2Cl and RGeMe2X respectively.
- Reddy, Prabhakar N.,Hayashi, Teruyuki,Tanaka, Masato
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p. 677 - 680
(2007/10/02)
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- Formation of Halide Complexes of Methyl- and Inorganic Germanium(IV) in Aqueous Hydrohalogenic Acid Solutions
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The reaction of methyl- and inorganic germanium(IV) hydroxides ((CH3)nGe(OH)4-n; n = 1, 2, or 3) with halide ions (X = Cl-, Br-, or I-) to form halide complexes ((CH3)nGeX4-n) in aqueous acidic solution has been investigated by liquid-liquid extraction, solid-liquid distribution (ion exchange), and 1H NMR spectrometry.It has been found that methylgermanium moieties are hard Lewis acids similarly to inorganic germanium(IV), because the stability constant of the halide complexes decreases in the order Cl- > Br- > I-.The stability constant for an X- ion increases as the number of methyl groups attached to the germanium atom increases.The species of inorganic-, monomethyl-, and dimethylgermanium are nonionic and have a tetrahedral structure in HX solution, and OJ- ions attached to the germanium atom are stepwise substituted by X- ions with an increase in HX activity.Trimethylgermanium alone forms a cation, when the activity of HX is not sufficiently high.These facts suggest that the transfer of a negative charge from methyl groups to the central germanium atom lowers the stability of the bond between the germanium atom (hard acid) and an OH- ion (hard base).
- Sohrin, Yoshiki
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p. 3363 - 3371
(2007/10/02)
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- Chemistry of heavy carbene analogues R2M (M = Si, Ge, Sn). 12. Concerted and nonconcerted insertion reactions of the germylene Me2Ge into the carbon-halogen bond
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During the reaction of Me2Ge with CCl3X (X = Cl, Br), PhCH2X (X = Br, I), and Ph2CHCl, 1H CIDNP is observed in the products of net insertion of Me2Ge into the carbon-halogen bond and in Me2GeX2 (X = Cl, Br). It is concluded that a two-step radical reaction takes place by an abstraction-recombination mechanism. No reaction takes place with alkyl halides that have a C-X bond dissociation energy of more than about 70 kcal/mol. Me2Ge is generated thermally at 70-95°C or photochemically from the 7-germabenzonorbornadiene 1 and reacts in both cases in the singlet state. The activation energy for forming Me2Ge from 1 is 19 kcal/mol for the reaction with CCl4. Insertion products are also formed with the alkenyl halides CH2=CHCH2X, PhCH=CHX (X = Cl, Br), and 2-bromobut-2-ene, but without showing CIDNP effects. Since Me2GeX2 was not found either, Me2Ge reacts in these cases in a nonradical manner. It does not react with 1-chlorocyclohexene, but it does react with Me2GeX2 under formation of digermanes and/or oligogermanes without CIDNP.
- K?cher, Jürgen,Lehnig, Manfred,Neumann, Wilhelm P.
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p. 1201 - 1207
(2008/10/08)
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- Tetramethylsilane in synthesis: Selective mono- and polymethylations of germanium tetrachloride
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In the presence of catalytic amounts of aluminum bromide (or chloride), selective mono-, di-, tri-, or tetramethylation of germanium tetrachloride was effected in high yield with tetramethylsilane (Me4Si) as the methylating reagent. According to the Me4Si/GeCl4 ratio, MeGeCl3, Me2GeCl2, Me3GeCl, and Me4Ge were prepared in 66, 86, 100, and 91% maximum yields, respectively. In these reactions, Me4Si was converted into Me3SiCl and subsequently Me2SiCl2. A mechanism for methylation is proposed, involving the initial formation of Me4Ge (observed regardless of the proportions of starting reagents) followed by disproportionation reactions, with methylchlorosilanes or -germanes present when the initial molecular ratio Me4Si/GeCl4 was lower than 4/1.
- Bordeau, Michel,Djamei, S. Mohammad,Dunoguès, Jacques
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p. 1087 - 1089
(2008/10/08)
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- Chemistry of Heavy Carbene Analogues R2M (M = Si, Ge, Sn). 8. Germylenes: Singlets or Triplets? Cheletropic Cycloadditions of Me2Ge and GeI2 to Conjugated Dienes
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Thermally generated germylenes Me2Ge undergo in solution under mild conditions (70-150 deg C) concerted 1,4-additions of the linear cheletropic type to certain 1,3-dienes.Thus, the highly reactive meso diallene 10a gives, in a about 1:1 ratio, only the two isomeric 1-germacyclopentenes 11a and 11b expected from front- and back-side attack of Me2Ge, whereas the D,L-diallene 10b produces only the third isomer, 11c, in accordance with this mechanism.The yields are about 70percent; the isomer purity is >/= 98percent.Likewise, two other E,E-1,4-disubstituted 1,3-butadienes give only the corresponding cis-2,5-disubstituted 1-germacyclopentenes 7a or 9a in 80percent or 30percent yields with an isomer purity of >/= 98percent (limit of the NMR analysis).Similarly, with GeI2 and 10a, only 14a and 14b are found, and 14c with 10b, as expected for a cheletropic reaction.Methylation of 14a-c yields the corresponding compounds 11a-c.Other mechanisms for these 1,4-additions are discussed but are highly unlikely: thermal germylenes Me2Ge and Ge2I behave as singlets.
- Schriewer, Michael,Neumann, Wilhelm P.
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p. 897 - 901
(2007/10/02)
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- 7-GERMANORBORNADIENES AND THEIR THERMAL CYCLOELIMINATIONS
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7 new 7-germanorbornadienes, crystalline and stable at 25 deg C, have been prepared by Diels-Alder reaction.They decompose thermally via a two step mechanism with an intermediate biradical, forming the benzene derivative and germylenes, R2Ge.
- Neumann, Wilhelm P.,Schriewer, Michael
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p. 3273 - 3276
(2007/10/02)
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