PNCNP Pincer Platinum Chloride Complex as a Catalyst for the Hydrosilylation of Unsaturated Carbon-Heteroatom Bonds

Abstract

A PNCNP pincer-ligated platinum(II) chloride complex [2,6-( t Bu 2 PNH) 2 C 6 H 3 ]PtCl (1a) was synthesized and fully characterized. Complex 1a was applied to the catalytic hydrosilylation of unsaturated carbon-heteroatom bonds. For comparison, the corresponding hydride complex [2,6-( t Bu 2 PNH) 2 C 6 H 3 ]PtH (1b) and the related POCOP pincer chloride complex [2,6-( t Bu 2 PO) 2 C 6 H 3 ]PtCl (1c) were also used to catalyze the reactions. It was found that 1a is a good catalyst for the hydrosilylation of both C�O and C�N bonds. Wide ranges of aldimines, ketimines, aldehydes, and ketones were hydrosilylated, and the expected amine or alcohol products were obtained in good to excellent yields. The reactions also feature good functional group compatibility. Complex 1a represents the most effective transition metal catalyst for the hydrosilylation of the C�N bond and is among the best transition metal catalysts for the hydrosilylation of the C�O bond. The reactions are likely catalyzed by a cationic platinum(II) species generated from complex 1a during the reactions.

Reactions of PNCNP and POCOP Pincer Platinum Hydride Complexes with Phenylacetylene and Carbon Disulfide: The Influence of the Pincer Backbone on the Structures of Unsaturated Auxiliary Ligands

“…The platinum hydride complexes 1a and 2a were previously prepared and fully characterized by different experimental techniques including multinuclear NMR, FTIR, and X-ray crystallography analysis. , To make comparisons, some selected spectral and structural data related to the hydride auxiliary ligand in complexes 1a and 2a are listed in Table .…”

“…As a result, complex 1a is expected to be more reactive against an electrophilic reagent. This is consistent with our previous observation that benzaldehyde is far easier to react with complex 1a to form the corresponding benzyloxide complex compared to complex 2a . , …”

“…We recently found that both platinum hydride complexes [2,6-( t Bu 2 PNH) 2 C 6 H 3 ]­PtH and [2,6-( t Bu 2 PO) 2 C 6 H 3 ]­PtH ( 1a and 2a , Chart ) are active catalysts for the hydrosilylation of aldehydes and ketones with phenylsilane. , The reaction mechanism is quite straightforward: insertion of the CO bond of the carbonyl complex into the Pt–H bond to form an alkoxide complex, which further reacts with a silane molecule to form silylether and regenerate the platinum hydride species. In the process of mechanistic investigation, we reacted 1a and 2a , respectively, with benzaldehyde in the absence of silanes.…”

Co‐Catalyzed Hydrosilylation of Ketones under Base‐Free Conditions: A Convenient Route to Silyl Ethers or Secondary Alcohols

“…The authors have cited additional references within the Supporting Information. [72][73][74][75][76][77][78][79][80][81][82][83][84][85]…”

Evaluating the Catalytic Activities of PNCNP Pincer Group 10 Metal Hydride Complexes: Pd-Catalyzed Reduction of CO2 to the Formic Acid Level with NH3·BH3 and NaBH4 under Ambient Conditions

“…Compared to other benzene-based PYCYP-type pincer complexes, the catalytic application of the PNCNP-type complexes has far less been explored. We recently investigated the structure, reactivity, and catalytic application of some group 10 metal PNCNP pincer complexes . We found that the palladium hydride complex [2,6-( t Bu 2 PNH) 2 C 6 H 3 ]­PdH ( 1b ) is a good catalyst for both direct hydration of nitriles to primary amides and dehydrogenation of methanol to formaldehyde under mild conditions .…”