Activation of the SiH bond of silanes in photochemical reactions with W(CO)6: Hydrosilylation of ketones and dehydrosilylation of alcohol by H2SiPh2

Activation of the Si–H bond of Et2SiH2 in photochemical reaction with W(CO)6: Spectroscopic characterization of intermediate W–Si compounds and the revisited crystal structure of the bis{(μ-η2-hydridodiethylsilyl)tetracarbonyltungsten(I)} complex [{W(μ-η2-H–SiEt2)(CO)4}2]

“…The 29 Si satellites on the latter hydride signal provided the 1 J Si-H value of 93 Hz, which is in a similar range as has recently been observed for similar g 2 -silane compounds ( 1 J Si-H = 98 Hz for [W(CO) 5 (g 2 -H-SiHPh 2 )]) [11], proving the correct assignment of this signal to the g 2 -H-SiHEt 2 moiety of the g 2 -silane complex. The 183 W satellites on the hydride signal allowed us to calculate the 1 J W-H = 38 Hz, which is very close to those observed for other a-agostic hydrides [10,11,20,21,38]. Based on these data, the signal can be assigned without a doubt to the intermediate compound [W(CO) 5 (g 2 -H-SiHEt 2 )] (A) (Scheme 1).…”

“…Careful analysis of the doublet signal at À8.25 ppm allowed us to detect 29 Si satellites that gave rise to the 1 J Si-H = 37 Hz. This coupling constant suggests a r (Si-H) interaction with the tungsten center [1,2,[10][11][12][13][14][15][16][16][17][18][19][20][21][22][23]. Compound B decays in toluene-d 8 solution in a few days and can be characterized in a freshly prepared sample obtained in a low temperature reaction (À10°C).…”

“…Recently, in photochemical reaction of group 6 metal hexacarbonyls with secondary and tertiary organosilanes, intermediate g 2 -silane complexes have been generated and characterized by IR and 1 H NMR spectroscopy and by photoacoustic calorimetry [10][11][12][13][14]. The activation of the Si-H bond of diphenylsilane in the photochemical reaction of W(CO) 6 has been applied in the hydrosilylation of ketones, RR 0 C@O (R = Me, R 0 ¼ Me, i Pr, n Pr, Ph) and in dehydrogenative silylation of 2-propanol [10].…”

“…The activation of the Si-H bond of diphenylsilane in the photochemical reaction of W(CO) 6 has been applied in the hydrosilylation of ketones, RR 0 C@O (R = Me, R 0 ¼ Me, i Pr, n Pr, Ph) and in dehydrogenative silylation of 2-propanol [10]. However, in our earlier studies we have found that the major product in photochemical reaction of W(CO) 6 with Ph 2 SiH 2 is the complex [(l-SiPh 2 ){W(CO) 5 } 2 ], which contains two W(CO) 5 moieties linked by a bridging diphenylsilylene ligand and a W-W bond [9].…”

Ruthenium carbonyl-catalysed Si–heteroatom X coupling (X = S, O, N)

“…Hydrosilylation of unsaturated bonds such as alkenes [1], alkynes [2] and carbonyls [3] is one of the more important processes involving organosilanes. Transition metal complexes containing iron [4,5], tungsten [6], molybdenum [7], manganese [8,9]], rhenium [10,11], rhodium [12], silver [13], nickel [14], and most recently ruthenium [2,15,16] have been used to catalyse such processes.…”