Identification of some intermediates in the titanocene-catalyzed dehydrogenative coupling of primary organosilanes

Redistribution reactions of alkoxy- and siloxysilanes, catalyzed by dimethyltitanocene

“…As long as the amount of 1 was less than sufficient to remove all active chlorine the strategy worked and it was rapidly converted to insoluble dichlorotitanocene (identified by comparison of its IR spectrum with that of an authentic sample). If the amount of 1 exceeded the amount necessary to remove all of the active chlorine, reduction of the excess 1 to the previously reported blue-black titanocene(II1) complexes occurred (1,3). These reduced titanocene species proved to be a potent catalyst for the disproportionation reaction and the trimethoxysilane was rapidly and completely converted to methylsilicate and silane.…”

“…The crystals were slightly soluble in toluene-d8 and the dark blue solution gave an 'H-NMR spectrum corresponding to a mixture of the cis-and transisomers of the dimer 2. The assignment was made by comparison of the spectrum with that of a sample of 2, made by reaction of methylsilane with 1, and by comparison with the spectrum of the previously characterized phenylsilyl analogue (1).…”

“…Reaction of 1,3,5,7-tetramethylcyclotetrasiloxane (D4') with 1 A reaction of 1 with a several molar excess of D4' in hydrocarbon solvent resulted in the rapid transformation of the orange 1 into dark blue reduced titanium species and subsequently to the formation of dark blue needles. Attempts to separate the crystals revealed that they were coated with a gelatinous material which rendered their purification impossible.…”

“…We have recently described the use of dimethyltitanocene, 1, as a catalyst for the oligomerization of organosilanes (1). In the course of a wider study of the reactions of silicon hydrides with group 4 metallocenes and their derivatives, we have now found that 1 is also a very effective catalyst for the redistribution of alkoxy-and siloxysilanes.…”

Preparation and X-ray Structure of Cp2Ti(Ph2SiH2)(PMe3)

“…6 Several of these complexes have been prepared and studied in detail. 3 Harrod and coworkers have isolated and characterized several dinuclear 4 and mononuclear 6 titanocene complexes from the reaction of dimethyttitanocene and phenylsilane (Figure 1). The compound Cp 2 Ti(pSi(H) 2 Ph)(Pi-H)TiCp 2 2t is of particular interest and can be viewed as being composed of a tlanocene(hydrido)sily1 complew jomnocene.…”