Mutual Placement of Isocyanide and Phosphine Ligands in Platinum(II) Complexes [PtHal₂L¹L²] (Hal = Cl, Br, I; L¹,L² = CNCy, PPh₃) Leads to Highly-Efficient Photocatalysts for Hydrosilylation of Alkynes

Abstract

A series of platinum complexes featuring phosphine and isocyanide ligands [PtX2(PPh3)(CNCy)] (X = Cl, Br, and I) as well as their parent phosphine [PtX2(PPh3)2] and isocyanide [PtX2(CNCy)2] analogues have been prepared and evaluated as catalysts for the photocatalytic hydrosilylation of alkynes. Under violet light irradiation (λmax = 400 nm), phosphine–isocyanides complexes [PtX2(PPh3)(CNCy)] gave high yields of silylated products (product yield up to 99%, TONs up to 1.98 × 103). The blue light irradiation (λmax = 450 nm) was more suitable for the parent phosphine complexes [PtX2(PPh3)2], which showed comparable efficiency (product yield up to 99%, TON up to 1.98 × 103), while isocyanide complexes [PtX2(CNCy)2] were not active.

Keywords

• isocyanide ligands
• platinum(II) complexes
• catalytic activity
• hydrosilylation
• photocatalysis