Tuning Activity and Selectivity during Alkyne Activation by Gold(I)/Platinum(0) Frustrated Lewis Pairs

Introducing
transition metals into frustrated Lewis pair systems
has attracted considerable attention in recent years. Here we report
a selection of three metal-only frustrated systems based on Au­(I)/Pt(0)
combinations and their reactivity toward alkynes. We have inspected
the activation of acetylene and phenylacetylene. The gold­(I) fragments
are stabilized by three bulky phosphines bearing terphenyl groups.
We have observed that subtle modifications on the substituents of
these ligands proved critical in controlling the regioselectivity
of acetylene activation and the product distribution resulting from
C­(sp)–H cleavage of phenylacetylene. A mechanistic picture
based on experimental observations and computational analysis is provided.
As a result of the cooperative action of the two metals of the frustrated
pairs, several uncommon heterobimetallic structures have been characterized.