Examination of Pt2dba3 as a “cocktail”-type catalytic system for alkene and alkyne hydrosilylation reactions

Abstract

Recent developments have underpinned that the creation of a potent catalytic system does not always necessitate the assembly of complex and costly organic ligands with transition metal compounds. Aligned with the principles of dynamic catalysis, a simpler methodology involving the use of regular complexes as catalyst precursors under carefully selected reaction conditions is feasible. The dynamic transformations that these metal compounds undergo can generate a catalyst system with acceptable selectivity and impressive performance characteristics. In our study, we utilized this approach for the hydrosilylation reaction, where we employed a readily available and stable tris(dibenzylideneacetone)diplatinum(0) complex (Pt₂dba₃) as a catalyst. Dynamic transformations of Pt₂dba₃ create a mixture of platinum-bearing compounds within the reaction system, forming a “cocktail”-type catalyst system with performance levels comparable to Karstedt's catalyst (Pt₂dvtms₃), a popular choice for hydrosilylation reactions. This “cocktail”-type catalyst was examined using a suite of methods, such as decomposition tests, monitoring of platinum nanoparticle formation via electron microscopy, and X-ray absorption fine structure analysis. The gathered data suggest that the reaction system contains both platinum molecular complexes and nanoparticles ranging between 1.6 and 2.6 nm in size. Furthermore, a mechanistic study scrutinizing the selectivity of the alkyne hydrosilylation reaction was conducted using DFT calculations. Molecular dynamics modeling of the key intermediate demonstrated the reversibility of the oxidative addition stage in the catalytic cycle and revealed possible mechanistic pathways for the external-ligand-free catalytic system.