Catalytic dehydrocoupling reaction

Up to now only permethylated or arylated polysilanes have been used as HTLs [2, 3]. The effects of other substituents on polysilanes synthesized by catalytic dehydrocoupling reaction on the device performance are investigated. 

With diphosphanes recently Stephan et al. reported an intriguing Al and P based macrocyclic structure [37]. A zirconium based catalyst precursor first was employed in the catalytic dehydrocoupling of the primary bidentate phosphane to give the tetraphosphane 6, (Scheme 4). The function of 6 as a molecular building block has been demonstrated by its reaction with MMe3(M = Al, Ga). Although, the gallium derivative 7 has not been... 

Catalytic dehydrocoupling, as shown in reaction (3), was pioneered by Fink (6-10) and later studied by Andrianov et al (43). Although Fink described the synthesis of the first polysilazanes, (9) reaction (23), this route to oligo- and polysilazanes remained unexplored... 

The Harrod group has investigated dehydrocoupling reactions of silanes with amines, hydrazines, and ammonia. In the presence of catalytic amounts of CuCl, hydrosilanes react with primary amines to give silazanes in high yields.180 For example, the reaction of phenylmethylsilane with benzylamine leads to a mixture of three products, with dependence on initial molar ratio of silane to amine [Eq. (72)]. Equimolar silane to amine ratio leads to formation of 1 as major product, whereas 2 is the main product if a 2 1... 

Polysilazanes can also be synthesized by catalytic dehydrocoupling (equation 4)28,29. The reaction works best with monosubstituted silanes (MeSiH3 is flammable) however, as with the ammonolysis reactions, molecular weights are normally less than 2000 Da. Hence, as-formed oligomers are not useful precursors. However, combinations of ammonolysis followed by catalytic dehydrocouphng provide access to useful precursors as discussed in the SiCN section. 

It is clear that catalytic dehydrocoupling is a versatile technique for the synthesis of E-E and E-E bonds. The scope of the methodology, in terms of the types of reactions that can be carried out and the selectivities that are possible, has been broadly established. There is still much to be done in unequivocally establishing the mechanisms and the types of catalytic intermediates involved. 

Based on these results. Maimers reported original tandem catalytic dehydrocoupling-hydrogenation reactions using Rh colloids and Me2NH-BH3 as a stoichiometric H 2 source (Scheme 11.15) [94]. The reaction was performed with cyclohexene... 

One remarkable application of the Re(I) complexes of type 16-19 is the catalytic dehydrogenation of amine boranes [54], In recent years, the research on amine borane R R NH-BHs (R R = alkyl, H) became an important topic based on their capability of chemical hydrogen storage [55-57], In this respect transition metal-catalyzed dehydrocoupling reactions of amine borane offer great potential for control over both extent and rate of hydrogen release [58, 59]. 

Si20N2 precursors have also been made via catalytic dehydrocoupling . Linear polysiloxazanes prepared via reaction 19 gave materials with M = 5-7 KDa however, the ceramic yields were poor. 

Catalytic reactions of silanes to give polysilanes and hydrogen, so-called dehydrocoupling reactions, are a promising route to functionalized, high molecular weight products. 

Zr -species could simply be by-products [77] and not be involved in the catalytic cycle as they could not be observed in all dehydrocoupling reactions [78]. Furthermore, no evidence for the existence of silyl radicals has been provided. 

Mono- and bis(silyl)platinum(II) complexes are believed to play important catalytic roles in hydrosilylation, dehydrocoupling, and double silylation reactions with disilanes and hydrosilanes. A stable, mono(silyl)platinum(II) complex has been prepared by the oxidative addition reaction of the sterically hindered, primary arylsilane 2,6-Mes2C6H3SiH3 (Mes = 2,4,6-trimethylbenzene) to the platinum(O) species [Pt(PPr3)3] in hexane solution at room temperature.133 The colorless product m-[PLl 1(2,6-Mes2C6II3(11 )2Si)(PPr3)2] (21) was isolated as the OPPr3 adduct, and its... 

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