Photochemistry of aryl-substituted trigermanes

Wakasa, Masanobu; Yoneda, Isao; Mochida, Kunio

doi:10.1016/0022-328x(89)87334-6

Cited by 32 publications

(19 citation statements)

References 8 publications

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“…This shift, in our opinion, could be connected with interaction of the p-system of TPN and the free p-orbital of germanium of dimethylgermylene. An identical effect was observed previously in the photocleavage of Me[Me 2 Ge] 6 Me and [Me 2 Ge] 6 in glasses (3-MP-isopentane, 4:1) containing benzene or naphthalene [9].…”

Section: Low-temperature Studysupporting

confidence: 80%

Re-examination of 7,7′-dimethyl-7-germanorbornadiene photocleavage in solution and in organic glasses

Kaletina

Korolev

2010

Res Chem Intermed

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Dimethylgermylene and its Ge=Ge doubly bonded dimer, tetramethyldigermene, have been characterized directly in solution by 308-nm laser flash photolysis in n-hexane solution, as well as 254-nm photolysis in hydrocarbon glasses at t = 77 K. An absorption band maximum of k max & 430 nm and molar absorption coefficient of e & 2,700 M -1 cm -1 have been shown to be attributable to low-temperature glasses, while the absorption band maximum of k max & 480 nm and molar absorption coefficient of e & 2,400 M -1 cm -1 have been shown to be related to dimethylgermylene in n-hexane solution. The molar absorption coefficient of tetramethyldigermene (k max & 380 nm) was determined to be e & 84,000 M -1 cm -1 . The germylene is formed via (formal) cheletropic photocycloreversion of 7,7 0 -dimethylgerma-1,4,5,6-tetraphenyl-2,3-benzo-norbornadiene. Tetramethyldigermene and 1,2,3,4-tetraphenylnaphthalene in the triplet state were formed, together with dimethylgermylene. We attempted to explain the various contradictory interpretations of experimental data existing in the literature on this reaction.

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Section: Low-temperature Studysupporting

confidence: 80%

Re-examination of 7,7′-dimethyl-7-germanorbornadiene photocleavage in solution and in organic glasses

Kaletina

Korolev

2010

Res Chem Intermed

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“…The UV-vis spectrum of GeMePh in a 3-methylpentane (3-MP) matrix at 77 K was reported in the late 1980s by two different groups; Ando et al (15) generated the species by photolysis of the 1,4-germanonaphthalene derivative 12 and reported a UV spectrum exhibiting λ max = 440 nm, while Mochida and co-workers (16) employed the photolysis of trigermane 13 and reported λ max = 456 nm in 3-MP at 77 K and λ max = 440 nm in cyclohexane solution at room temperature. The latter group also reported rate constants for reaction of the species in cyclohexane solution with DMB (k = 2.2 × 10 6 (mol/L) -1 s -1 ), Et 3 SiH (k = 4.1 × 10 6 (mol/L) -1 s -1 ), and CCl 4 (k = 6.5 × 10 7 (mol/L) -1 s -1 ) (16). A transient exhibiting a similar UV absorption spectrum but much different reactivity toward DMB and CCl 4 , from flash photolysis of poly(methylphenylgermylene) (14), was later assigned to GeMePh by the same group (17).…”

Section: Discussionmentioning

confidence: 96%

Direct detection of methylphenylgermylene and 1,2-dimethyl-1,2-diphenyldigermene — Kinetic studies of their reactivities in solution

Leigh¹,

Dumbrava²,

Lollmahomed³

2006

Can. J. Chem.

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Photolysis of 1,3,4-trimethyl-1-phenylgermacyclopent-3-ene (5) in hydrocarbon solvents containing isoprene, methanol, or acetic acid affords 2,3-dimethyl-1,3-butadiene (DMB) and the expected trapping products of methyl phenylgermylene (GeMePh) in chemical yields exceeding 90%. The germylene has been detected in hexane solution by laser flash photolysis as a short-lived species (τ ~ 2 µs) exhibiting a UV-vis absorption spectrum centered at λmax = 490 nm. It decays with second-order kinetics and a rate constant close to the diffusion-controlled limit, with the concomitant growth of a second longer-lived transient (λmax = 420 nm) that is assigned to a mixture of (E)- and (Z)-1,2-dimethyl-1,2-diphenyldigermene (4). Absolute rate constants have been determined for the reactions of the germylene with primary and tertiary amines (n-BuNH2 and Et3N, respectively), acetic acid (AcOH), a terminal alkyne and alkene, isoprene, DMB, CCl4, and the group 14 hydrides Et3SiH and Bu3SnH. GeMePh is slightly more reactive than GePh2 towards all the reagents studied in this work; both are significantly less reactive than GeMe2 toward the same substrates. Absolute rate constants for the reactions of 4 have also been measured or assigned upper limits in every case and are compared to previously reported values for tetraphenyl- and tetramethyl-digermene with the same reagents.Key words: germylene, digermene, kinetics, laser flash photolysis, germirane, germirene, vinylgermirane, complex, UV–vis spectrum, insertion, addition.

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“…(14) Extrapolation of the observed rate constants with the aid of RRKM calculations gave the high pressure limiting rate constants at each temperature, which follow the Arrhenius equation with the parameters listed in Table 8. The reaction of GeH 2 with ethylene slows down with an increase in temperature and the activation energy ob tained for this reaction is negative ( Table 8).…”

Section: Methodsmentioning

confidence: 99%

Gas phase kinetic and theoretical studies of reactions of germylenes and dimethylstannylene

et al. 2005

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The results of time resolved gas phase studies of labile germylenes (GeH 2 and GeMe 2 ) and dimethylstannylene (SnMe 2 ) reactions reported to date are considered together with data of quantum chemical investigations of the potential energy surfaces of these systems. Reaction mechanisms are discussed. A comparison of reactivity in the series of carbene analogs, ER 2 (E = Si, Ge, Sn, R = H, Me), is made.

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Photochemistry of aryl-substituted trigermanes

Cited by 32 publications

References 8 publications

Re-examination of 7,7′-dimethyl-7-germanorbornadiene photocleavage in solution and in organic glasses

Re-examination of 7,7′-dimethyl-7-germanorbornadiene photocleavage in solution and in organic glasses

Direct detection of methylphenylgermylene and 1,2-dimethyl-1,2-diphenyldigermene — Kinetic studies of their reactivities in solution

Gas phase kinetic and theoretical studies of reactions of germylenes and dimethylstannylene

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