Germylene and Stannylene Anion-Radicals: Generation and Electronic Structure

Egorov, M. P.; Нефедов, О. М.; Lin, Tien‐Sung; Gaspar, Peter P.

doi:10.1021/om00003a070

Cited by 61 publications

(21 citation statements)

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“…[31] These anion radicals were prepared by the reduction of Lappert's germylene [(Me 3 Si) 2 CH] 2 Ge: and stannylene [(Me 3 Si) 2 CH] 2 Sn: with sodium mirror in THF (Scheme 10). Although both germylene anion radical 13 and stannylene anion radical 14 were not indefinitely stable in solution at room temperature (the lifetime for 13 was about 1.5 h, whereas for 14 it was several minutes), it was possible to characterize them by EPR spectroscopy.…”

Section: Anion Radicals Of Heavy Carbene Analoguesmentioning

confidence: 99%

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Si‐, Ge‐, and Sn‐Centered Free Radicals: From Phantom Species toGrams‐Order‐Scale Materials

Lee

Sekiguchi

2005

Eur J Inorg Chem

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Recent developments in the field of the stable free radicals of heavier group 14 elements are reviewed, covering both neutral and charged radical species. The electronic and crystal‐structural features of these radicals, both in the solid state and in solution, are compared with each other. The most important parameters affecting the stability, geometry and electronic configuration of the radicals are discussed on the basis of the latest experimental and computational data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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Section: Anion Radicals Of Heavy Carbene Analoguesmentioning

confidence: 99%

“…[31] The small values of the hfcc's [a( 73 Ge) = 1.25 mT and a( 119,117 Sn) = 11.6 mT] make possible a reliable assignment of both anion radicals 13 and 14 to a class of π radicals with the 2 B 1 ground electronic state.…”

Section: Anion Radicals Of Heavy Carbene Analoguesmentioning

confidence: 99%

Si‐, Ge‐, and Sn‐Centered Free Radicals: From Phantom Species toGrams‐Order‐Scale Materials

Lee

Sekiguchi

2005

Eur J Inorg Chem

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“…54 Prior to our study, an ESR study of related radical anions of stable germylene and stannylene was reported. 55 West et al reported that the reduction of a stable diaminosilylene with potassium graphite in THF gave the corresponding 1,2-dilithiodisilane, which would be formed via fast dimerization of the silylene radical anion. 53 A closely related lithiosilyl radical was observed by ESR by Apeloig et al 56 One-electron reduction of dialkylsilylene 1 using alkali metals generated the corresponding radical anion as a relatively persistent species at low temperatures in solution (Eq.…”

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confidence: 99%

A Helmeted Dialkylsilylene

Kira¹,

Iwamoto²,

Ishida³

2007

Bulletin of the Chemical Society of Japan

102

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Structural characteristics, spectroscopic properties, and unique reactions of a helmeted dialkylsilylene, 2,2,5,5-tetrakis(trimethylsilyl)silacyclopentane-1,1-diyl, that was synthesized as the first isolable dialkylsilylene and its application to the synthesis of novel silicon unsaturated compounds are surveyed. The silylene was found to be the least electronically perturbed among known stable silylenes by 29 Si NMR and UV-vis spectroscopies. The silylene reacts not only with well-known trapping reagents for transient silylenes, such as alcohols, triethylsilane, and 2,3-dimethylbutadiene, but also with less reactive haloalkanes and halosilanes to give the corresponding adducts. One-electron reduction of the silylene using alkali metals affords the corresponding radical anion as a relatively persistent species at low temperatures in solution. Irradiation of the silylene using visible light generates a singlet excited state with a lifetime of 80.5 ns, which reacts with various aromatic compounds and alkenes to give the corresponding silepins and siliranes in a highly regio-and stereoselective manner. The silylene is utilized for the synthesis of unique silicon unsaturated compounds, such as Si=X doubly bonded compounds (X ¼ S, Se, Te, C=NR, etc.), a trisilaallene, a 1,3-disilagermaallene, and silylene transition-metal complexes.

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“…Because dialkylmetallylenes have low‐lying LUMO ( n p z ) and high‐lying nonbonding HOMO(n), the corresponding radical anions and radical cations may be generated by one‐electron reduction and oxidation, respectively. In fact, the anion radicals of germylene 6b and stannylene 6c were generated and investigated by ESR by Egorov et al30 West et al have reported that the reduction of diaminosilylene 5a with potassium graphite gave the corresponding 1,2‐dipotassiodisilane via fast dimerization of the corresponding silylene anion radical 31…”

Section: Reactionsmentioning

confidence: 99%

Comparative chemistry of isolable divalent compounds of silicon, germanium, and tin

Kira

Ishida

Iwamoto

2004

The Chemical Record

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Recent studies of the synthesis, structures, spectroscopic properties, and reactions of a series of isolable metallylenes (R2E:, E = Si (1), Ge (2), and Sn (3); R2 = 1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl) are summarized. Because these group-14 metallylenes bear the same helmet-like ligand, a straightforward discussion of the element-dependence of the intrinsic properties of the group-14 element divalent compounds is possible. All these metallylenes were monomeric both in solution and in the solid state, indicating the effective steric protection by the ligand against dimerization. A small sigma-pi conjugation between C-Si(substituent) sigma orbitals and the vacant npz orbitals of divalent atoms in R2E: exists and the extent decreases in the order E = Si > Ge > Sn, as evidenced by UV-vis and NMR spectroscopies and X-ray crystallography. However, the extent of the sigma-pi conjugation in metallylenes 1-3 was much smaller than the electron-donating effects of neighboring nitrogen atoms in known stable cyclic diamino-substituted metallylenes, and hence metallylenes 1-3 are regarded as the least electronically perturbed. Comparative studies of the unique reactions among these metallylenes are also discussed.

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Germylene and Stannylene Anion-Radicals: Generation and Electronic Structure

Cited by 61 publications

References 0 publications

Si‐, Ge‐, and Sn‐Centered Free Radicals: From Phantom Species toGrams‐Order‐Scale Materials

Si‐, Ge‐, and Sn‐Centered Free Radicals: From Phantom Species toGrams‐Order‐Scale Materials

A Helmeted Dialkylsilylene

Comparative chemistry of isolable divalent compounds of silicon, germanium, and tin

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