Disilene system (R2Si:SiR2). The tetra-tert-butyl derivative

Abstract

W ( T~-C~M~~-~-B U ) C~~]~, 83511-04-0; ZnMe2, 544-97-8; ZII(CH~CM~~)~, 54173-23-8.(16) The theoretical distribution is (1a4W)3 = 63.6%, (1MW)2(183W) = 31.0%, (184W)(183W)2 = 5.170, and (1s3W)3 = 0.3%. Half of the triplet pattern for (''W)(183w)2 is found under the main peak due to the hydride in (17) Bau, R.; Carroll, W. E.; Teller, R. G.; Koetzle, T. F. Summary: Low-temperature photolysis of 2,3-benzo- 7,7,8,8-tetra-tert-butyl-7,8disilabicyclo [2.2.2]octa-2,5diene provides, in addition to naphthalene, tetra-tert-butyldisilene, which exhibits UV absorption maxima at 305 ( E 5200) and 433 nm (2800). This disilene is thermally unstable and has a half-life of only several hours at room temerature (ca.

Silylene oxonium ylides: di-tert-butylsilylene insertion into C–O bonds

“…Because large amounts of by-product 12 were observed with several protecting groups and different substitution patterns at the α-position of the allylic ether, formation of the disilane by-product 12 appeared to be independent of electronic and steric factors. A mechanism for generation of disilane 12 , illustrated in Scheme 3, could be envisioned from tetra- t -butyldisilene 19 forming by way of dimerization of free silylene 17, 18. Coordination of the disilene to the oxygen atom of 18 to form disilyl ylide intermediate 20 and subsequent elimination of diene 21 would provide disilane 12 .…”

STABLE METALLA-ALKENES >M=C< AND DIMETALLA-ALKENES >M=M< (M : Si, Ge, Sn)

“…(4) this route (retro Diels-Alder reaction by photolysis) was only used for the synthesis of metastable tBu2Si=SitBu2, which was characterized by UV [55], (5) cis-trans isomerisation. (by photolysis or not) or rearrangement of a disilene involving an exchange of substituents between two silicon atoms.…”

Photochemical Generation and Characterization of Di-tert-butylsilylene (SitBu2) in Solution

“…Similarly, photolysis of hexa- tert -butylcyclotrisilane ( 7 ) in the presence of various trapping agents generates compounds consistent with the formation of both Si t Bu 2 and the marginally stable tetra- tert -butyldisilene ( 8 ) as photoproducts (eq ), and has been used extensively by Weidenbruch and co-workers for the preparation of a wide range of novel organosilicon compounds . An early laser flash photolysis study of 7 reported the observation of a transient product exhibiting λ max ≈ 440 nm and lifetime τ ≈ 12 ms in degassed cyclohexane, which was assigned to Si t Bu 2 on the basis of its lifetime in spite of the spectroscopic similarities to 8 . The silylene was subsequently characterized by UV–vis and IR spectroscopy in low temperature matrixes after generation by two-photon photolysis of diazidodi- tert -butylsilane ( 9 ; eq 3), and found to exhibit a broad visible absorption band over the ca.…”