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-Bu2bipy) and the alkynyl
gold compounds (PPh4)[Au(C⋮Cpy)2] and (PPh4)[Au(C⋮C−C6H4−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.