Cleavage of the carbon-silicon bond in [tris(trimethylsilyl)methyl]diphenyl-chlorogermane in the presence of fluoride ion

Zemlyanskii, N. N.; Борисова, И. В.; Bel'skii, V. K.; Kolosova, N. D.; Beletskaya, I. P.

doi:10.1007/bf00953506

Cited by 2 publications

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“…As in the case of 3a , both of the planar, square dimetallacyclic fragments in 3b contain ring atoms possessing distorted tetrahedral geometries. The transannular Ge−Ge distances in both of the independent molecules of 3b ( d av ∼2.78 Å) are similar to those previously reported in the literature for other 1,3-digermacyclobutane derivatives. , …”

Section: Resultssupporting

confidence: 88%

Homo- and Cross-[2+2]-Cycloaddition of 1,1-Diphenylsilene and 1,1-Diphenylgermene. Absolute Rate Constants for Dimerization and the Molecular Structures and Photochemistry of the Resulting 1,3-Dimetallacyclobutanes

et al. 1999

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Absolute rate constants for the head-to-tail [2+2]-dimerization of 1,1-diphenylsilene and 1,1-diphenylgermene have been determined in hexane and isooctane solution at 23 °C by laser flash photolysis, using the corresponding 1,1-diphenylmetallacyclobutanes as precursors. This requires knowledge of the molar extinction coefficients at the UV absorption maxima of the two transient species, which have been determined by a transient actinometric procedure. The rate constants for dimerization of the two compounds are similar and within a factor of about 2 of the diffusional rate constant in both cases. The 1,3-dimetallacyclobutane dimerization products have been prepared by direct photolysis of the corresponding 1,1-diphenylmetallacyclobutanes in dry isooctane. In addition, 1,1,3,3-tetraphenyl-1-germa-3-silacyclobutane has been prepared by photolysis of a 1:1 mixture of the two metallacyclobutanes. The solid-state structures of the three 1,3-dimetallacyclobutanes have been determined by single-crystal X-ray crystallography, and their photochemistry has been studied. Laser flash and/or steady-state photolysis experiments indicate that all three compounds cyclorevert to the corresponding 1,1-diphenylmetallaenes upon photolysis in hydrocarbon solvents, most likely via the same (•M−C−M‘−C•) 1,4-biradical intermediates which link the metallaenes with their corresponding dimers via stepwise dimerization mechanism. The quantum yield for photocycloreversion of the digermacyclobutane is roughly one-fourth that of 1,1-diphenylgermacyclobutane. However, it is about 3 times higher than that for the silagermacyclobutane and roughly 15 times higher than that for the disilacyclobutane. Singlet lifetimes have been determined for the metallacyclobutanes and the disila- and digermacyclobutanes using single photon counting techniques. The implications of these results for the mechanisms of the head-to-tail [2+2]-dimerization of silenes and germenes are discussed.

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Section: Resultssupporting

confidence: 88%

Homo- and Cross-[2+2]-Cycloaddition of 1,1-Diphenylsilene and 1,1-Diphenylgermene. Absolute Rate Constants for Dimerization and the Molecular Structures and Photochemistry of the Resulting 1,3-Dimetallacyclobutanes

et al. 1999

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“…Note that the chemical behaviors of 10 and 19 are completely different, since 19 easily dimerizes, whereas 10, substituted on germanium by two phenyl groups, which are slightly bulkier than the methyl group (as in the case of 19), cannot dimerize and instead loses a trimethylsilyl group. 21 Germene 19 has been thoroughly characterized by its chemical reactivity: both by insertion into the O-H bond of alcohols25® and by ene reactions. 24,25® Various cycloadditions24,25 have also been observed: [2 + 2] cycloadditions are obtained with the C=C bond of CH2=CHOMe25® and the C=0 bond of ketones,25®…”

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confidence: 99%