The reaction of the Pt complexes cis-[Pt(CH3 )2 {R2 P(Ind)}2 ] (Ind=2-(3-methyl)indolyl, R=Ph (1 a), 4-FC6 H4 (1 b), 4-CF3 C6 H4 (1 c)) with HF afforded the fluorido complexes trans-[Pt(F(HF)2 )(CH3 ){R2 P(Ind)}2 ] 2 a-c, which can be converted into trans-[Pt(F)(CH3 ){R2 P(Ind)}2 ] (3 a-c) by treatment with CsF. Addition of 3-hexyne to 2 a-c gave alkyne complexes trans-[Pt(C,C-η2 -C2 H5 C≡CC2 H5 )(CH3 ){R2 P(Ind)}2 {F(HF)2 }] (4 a-c) at which a fluoride is stabilised as polyfluoride in the coordination sphere by hydrogen bonding to the indolyl-substituted phosphine ligands. Subsequent heating of a solution of 4 a in the presence of PVPHF led to fluoroalkene formation. Selective catalytic hydrofluorination of alkynes to yield (Z)-fluoroalkenes were developed. The ability of hydrogen bonding to polyfluoride favours the fluorination step as demonstrated by studies with complexes bearing no indolyl groups at the phosphine ligands.
Keywords: Fluorido Complexes; Hydrofluorination; Hydrogen Bonding; Platinum; Polyfluorides.
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