Ultraviolet properties of compounds containing the silicon-silicon bond

Intuitive Understanding of σ Delocalization in Loose and σ Localization in Tight Helical Conformations of an Oligosilane Chain

“…The left-hands ide of Figure2 compares the low-temperature UV absorption spectra of the linear permethylated oligosilanes Si n Me 2n + 2 (n = 4, 6, 8, and 10), [24,[42][43][44][45][46][47][48] believed to be due to the all-[t]c onformers with ar andomly distributed helicitys ense, [4] with the transition energies and oscillator strengths calculated (TD-DFT/TZ)f or the all-[t]c onformers all-[t]-1 [4] to all-[t]-1 [10]. The only observedi ntensea bsorption maximum gradually shifts from 43 100 cm À1 in Si 4 Me 10 to 34 100 cm À1 in Si 10 Me 22 , and gains af actor of nearly 10 in intensity in the process.…”

Monomeric organosilicon compounds with polyfunctional groups

“…As reported earlier in a study of fully permethylated straight-chain polysilanes, the position of maximum absorp tion arid the molar absorptivity increase regularly with in creasing chain length (82). The conjugated system is also lengthened by replacement of a methyl group with substituents such as a phenyl or vinyl group which increase the and molar absorptivity.…”

“…Comparison of our studies, shown in Tables 20 and 21, with the ultraviolet spectral data of the Me-tSiMegï^-Me series (82) indicates that little or no change is observed in the X . of polydimethylsilanes substituted with a terminal methyl group, chlorine or hydrogen atom.…”

Photoinduced Rearrangement Reaction of 2-(Pentamethyldisilanyloxymethyl) phenylpentamethyldisilane

“…It is well known that disilane molecules having a siliconsilicon σ bond show unique properties in the photochemical [1][2][3][4] and thermal reactions 5 and in the transition metal catalyzed reactions [6][7][8][9][10][11][12][13][14] since the first reports on the unusual electronic spectra of aryldisilanes by Sakurai et al, 15 Gilman et al 16 and Hague et al 17 in 1964. In the context of our interest on the synthesis of silicon containing heterocyclic compounds by the photoreactions of ortho-substituted arylalkynyldisilanes [18][19][20][21][22][23][24][25][26][27][28][29] and aryldisilanes, 30,31 we have very recently reported on the photoreaction of (2-pentamethyldisilanyloxy)phenylpentamethyldisilane 32 in the presence of methanol or acetone affording a novel intramolecular photoproduct via silene intermediate.…”