Silylene water

Finally, atomic and molecular proton affinities (PAs) have also been evaluated for various functionals for ammonia, water, acetylene, silane, phosphine, silylene, hydrochloric acid, and molecular hydrogen. For G2 and G3 theories, the mean unsigned error in PAs is 1.1 and... 

Not surprising, the insertion of silylene into the S-H bond of hydrogen sulfide shows qualitatively the same features as the reaction with water. However, the complexation energy (36.0 kJ mol-1) and the activation energy (56.1 kJ moL1) of the rearrangement are lower at the MP4SDTQ/6-31G // 3-21G level.14 A compi increases to 55.3 kj mol-1 when calculated at the MP2/CEP-31g(2d,p)//MP2/CEP-31g(2d,p) level.83... 

The stable silylenes react, however, with water and alcohols, by straightforward insertion into O—H bonds. Silylenes 59, 61 and 62 all react with methyl iodide, inserting into the C—I bond. Examples of these reactions are shown for 59 in Scheme 18. Compounds 59 and 61 also react with elemental chalcogens. For 61 with Ss, Ses or Te 37°, and for 59 with... 

An early inorganic example of a silylene complex is HSiOH—OH2, obtained by the reaction of silicon atoms with water. See Z. K. Ismail, R. M. Hauge, L. Fredin, J. W. Kauffman and J. L. Margrave, J. Chem. Phys., 77, 1617 (1982). 

Silylene transfer to a, j3-unsaturated esters produces oxasilacyclopentenes, which undergo reaction with water to give /S-silyl ester (38) with high diastereoselectivity. 

In 2001, a possibility of detectable differences in chiroptical and achiral physicochemical experiments between an enantiomeric pair of poly[bis (S)-3,7-dimethyloctyl silylene] (33-SS) and poly[bis (R)-3,7-dimethyloctyl silyl-ene] (33-RR) (Scheme 10) was reported [119]. The polymers bearing two identical chiral side groups with 96% ee have nearly degenerate doublewell energy potentials, leading to PM-transition at - 65 °C in isooctane. Recently, Shinitzky et al. reported positive experimental results that show distinct differences in helix-coil transition behavior between synthetic d-and L-oligopeptides with 24 identical residues dissolved in water by CD and isothermal titration calorimetry experiments [120]. They assumed that ortho-water in the triplet state (75% of bulk water) is responsible for the LD-differences [121]. 

Silver-catalyzed silylene transfer was reported as a general method for the synthesis of silaziridines <07OL3773>. Despite the sensitivity of silaziridines to water and air, these intriguing compounds could be isolated in good yield. 

Silylene 5 is remarkably stable, in sharp contrast to previous silylenes. It was purified by vacuum distillation at 85 °C (1 Torr) and survives heating in toluene solution to 150 °C for many months. The pure compound decomposes only at its melting point, 220 °C. Compound 5 is also less reactive than usual silylenes. It is inert to triethylsilane, diphenylacetylene, or 2,3-dimethylbutadiene, all of which react rapidly with conventional silylenes. Moreover, it does not form acid-base complexes with Lewis bases such as THF and pyridine, although normal silylenes do [19]. However, 5 does react with methanol, water, and dioxygen. 

Silylene complexes show high reactivities toward nucleophiles such as water, alcohols, ketones, and isocyanates [3, 4]. Some typical reactions of (OC)4Fe=SiR2(HMPA) are summarized in Scheme 1 [2]. The dimerization forming the diferradisilacyclobutane is the only known [2+2]-cycloaddition starting from 1. The photochemical reaction of 1 with 2,3-dimetylbutadiene... 

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