Abstract
The reaction of the Pt complexes cis-[Pt(CH(3) )(2) {R(2) P(Ind)}(2) ] (Ind=2-(3-methyl)indolyl, R=Ph (1 a), 4-FC(6) H(4) (1 b), 4-CF(3) C(6) H(4) (1 c)) with HF afforded the fluorido complexes trans-[Pt(F(HF)(2) )(CH(3) ){R(2) P(Ind)}(2) ] 2 a-c, which can be converted into trans-[Pt(F)(CH(3) ){R(2) 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-η(2) -C(2) H(5) C≡CC(2) H(5) )(CH(3) ){R(2) 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.