Thermolysis of a siladigermirane: evidence for the formation of a germasilene

Baines, Kim M.; Cooke, Jeffrey A.

doi:10.1021/om00056a004

Cited by 73 publications

(62 citation statements)

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“…Baines et al have observed that tetramesitylgermasilene 1 reacts with methanol at −78°C giving the corresponding methanol adduct 21, while the reaction of 1 with triethylsilane at higher temperatures gives interestingly 22, an addition product to trimesitylsilyl(mesityl)germylene 1' formed via the rearrangement of 1 (Scheme 2). [29][30][31] The results indicate that though germasilene 1 is generated in a high yield at −78°C, 1 is equilibrated with silylgermylene 1' at higher temperatures.…”

Section: Reactions Of Germasilene 8bmentioning

confidence: 91%

“…Observation of two distinct signals with reasonable chemical shifts due to t-BuMe 2 Si silicon nuclei in the 29 Si NMR of germasilene 8b indicates that facile exchange among four t-BuMe 2 Si groups in 8b does not occur at room temperature. The 29 Si NMR chemical shift for unsaturated Si nucleus in 8b is very close to that in 8a, in contrast to that in germasilene 4 [34,35], which is highly shielded with the chemical shift of +25.1 ppm. It is suggested that the polarity of Ge=Si bond is very small intrinsically but significantly affected by the electronic substituent effects.…”

Section: Comparison Of Nmr and Uv-vis Spectramentioning

confidence: 99%

“…Dibrominatedgermylsilane 15 obtained by the reaction of germylsilane 14 with bromine is reduced by sodium in toluene at room temperature giving 8b in 32% isolated yield as yellow orange crystals. The structure of 8b was determined by 1 H, 13 C, and 29 Si NMR spectroscopies and X-ray crystallography.…”

Section: Synthesis Of Tetra(t-butyldimethylsilyl)germasilene (8b)mentioning

confidence: 99%

“…Among 8a-8c 29 Si NMR and UV-vis absorption spectra of 8a-8c are listed in Table 2. Observation of two distinct signals with reasonable chemical shifts due to t-BuMe 2 Si silicon nuclei in the 29 Si NMR of germasilene 8b indicates that facile exchange among four t-BuMe 2 Si groups in 8b does not occur at room temperature.…”

Section: Comparison Of Nmr and Uv-vis Spectramentioning

confidence: 99%

“…Although seven stable germasilenes (R 2 Ge=SiR' 2 ) have been synthesized so far (Chart 1) as a typical class of unsymmetrical dimetallenes, our knowledge of Ge=Si double bonds is still very limited. Tetramesitylgermasilene 1 was first prepared by the photolysis of hexamesitylcyclogermadisilane by Baines et al in 1991, while not isolated [29][30][31]. Two cyclic germasilenes 2 [32] and 3 [33] and two acyclic germasilenes 4 [34,35] and 5 [36] have been isolated and characterized by Sekiguchi et al We have reported on the synthesis and properties of two germasilaallenes 6 [37] and 7 [38] having cumulated Ge=Si double bonds.…”

Section: Introductionmentioning

confidence: 99%

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Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Iwamoto

Okita

Yoshida

et al. 2010

Silicon

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Tetra(t-butyldimethylsilyl)germasilene (8b) was synthesized using di(t-butyldimethylsilyl)hydridogermyllithium prepared by the germa-metallation of the corresponding dihydridogermane. Tetrasilylgermasilene 8b was obtained as single crystals by recrystallization from hexane at room temperature. The molecular structure of 8b is similar to those of the corresponding disilene 8a and digermene 8c but with an intermediate unsaturated bond length and twist angle between those of 8a and 8c. The reactions of 8b with methanol and 2,3-dimethylbutadiene gave the corresponding adducts. Equilibrium between 8b and the corresponding (trisilylsilyl)(silyl)germylene is suggested by the reaction of 8b with triethylsilane giving the germylene insertion product into the Si-H bond.

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Section: Reactions Of Germasilene 8bmentioning

confidence: 91%

Section: Comparison Of Nmr and Uv-vis Spectramentioning

confidence: 99%

Section: Synthesis Of Tetra(t-butyldimethylsilyl)germasilene (8b)mentioning

confidence: 99%

Section: Comparison Of Nmr and Uv-vis Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Iwamoto

Okita

Yoshida

et al. 2010

Silicon

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Heavy Analogs of Alkenes, 1,3‐Dienes, Allenes and Alkynes: Multiply Bonded Derivatives of Si, Ge, Sn and Pb

Lee

Sekiguchi

2010

Organometallic Compounds of Low‐Coordinate Si, Ge, Sn and Pb

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Unsaturated hydrocarbons, alkenes, alkynes and dienes are among the most fundamental classes of organic compounds. The great variety and richness of organic chemistry are to a large extent caused by the disposition of carbon to form highly reactive carbon-carbon and carbon-heteroatom multiple bonds. Standard textbooks on organic chemistry describe the C=C double bond as one made of a σ -bond, formed by the linear end-on overlap of sp 2 -hybrid orbitals of each carbon partner (sp 2 -sp 2 interaction), and a π -bond, formed by the side-on overlap of unhybridized 2p-orbitals (2p π -2p π interaction). Analogously, the carbon-carbon triple bond consists of a σ -bond, formed by the linear end-on overlap of the two sp-hybrids (sp-sp interaction), and two mutually orthogonal π -bonds, each formed by the side-on overlap of unhybridized 2p-orbitals (2p π -2p π interaction). Because the s-character of the hybrid orbitals used for the formation of carbon-carbon bonds progressively increases from the single (sp 3 -sp 3 ) to the double (sp 2 -sp 2 ) and triple (sp-sp) bonds, C=C double bonds are shorter (and stronger) than C-C single bonds, and C≡C triple bonds are shorter (and stronger) than C=C double bonds. In accord with their hybridization types, the geometry of the carbon-carbon double bond in alkenes R 2 C=CR 2 is planar with an idealized R-C=C bond angle of 120 • , and the geometry of the carbon-carbon triple bond in alkynes R-C≡C-R is linear with an idealized R-C≡C bond angle of 180 • .The structures and bonding of the alkene analogs of heavy group 14 elements, both in the crystalline form and in solution, are sharply distinctive from those of their organic counterparts (alkenes); therefore, before proceeding to the discussion on each class of heavy alkenes we will briefly comment on the specific structural features of the title compounds. Structure and bondingIn contrast to organic alkenes, which are typically planar and feature diagnostically short double bonds (av. 1.34Å for >C=C< vs av. 1.54Å for >C-C<), their analogs of the heavy group 14 elements >E=E< (E = Si-Pb) revealed diverse types of structural modes sharply distinctive from those of their organic counterparts. Thus, apart from the stretching of the E=E bond descending group 14, there are two fundamental structural deformations characteristic of heavy alkenes >E=E< and leading to their departure from planarity: trans-bending at E centers and twisting about the E=E bond. The peculiar trans-bending geometry, resulting in the overall pyramidalization at the heavy group 14 elements, was rationalized in the framework of two different MO models providing alternative explanations for this phenomenon. 5 The first qualitative model considered formation of the double bond as a result of the interaction of two monomeric carbene units, taking into account the different groundstate multiplicities of carbenes and their heavy analogs. Thus, interaction of the two monomeric carbenes, which typically have triplet ground states (or alternatively, singlet ground states with ...

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Recent Advances in Acidity, Complexing, Basicity andH‐Bonding of Organo Germanium, Tin and Lead Compounds*In this chapter, full lines are used both for covalent chemical bonds as well as for partial bonds and for coordination.

Rienäcker

Klapötke

2009

Patai's Chemistry of Functional Groups

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Thermolysis of a siladigermirane: evidence for the formation of a germasilene

Cited by 73 publications

References 1 publication

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Heavy Analogs of Alkenes, 1,3‐Dienes, Allenes and Alkynes: Multiply Bonded Derivatives of Si, Ge, Sn and Pb

Recent Advances in Acidity, Complexing, Basicity andH‐Bonding of Organo Germanium, Tin and Lead Compounds*In this chapter, full lines are used both for covalent chemical bonds as well as for partial bonds and for coordination.

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