Unexpected Alkyne Transfer between Gold and Rhenium Atoms and Its Application to the Synthesis of Alkynyl Rhenium(I) Compounds

The reaction between the rhenium complexes [Re(OTf)(L)(CO) 3 ] (L = bipy, t -Bu 2 bipy) and the alkynyl gold compounds (PPh 4 )[Au(C⋮Cpy) 2 ] and (PPh 4 )[Au(C⋮C−C 6 H 4 −C⋮Cpy) 2 ] in a 2:1 molar ratio affords binuclear cationic rhenium(I) derivatives through a previously unreported alkyne transmetalation process involving the two metals. This reaction can be used for the synthesis of mononuclear rhenium alkynyls by changing the molar ratio between the reagents to 1:1. These new luminescent complexes were characterized spectroscopically. The X-ray structure of the binuclear compound [{Re(bipy)(CO) 3 } 2 (μ-C⋮Cpy)](OTf) ( 2 ) was also determined.