Rhenium Selenide Clusters Containing Alkynyl Ligands: Unexpected Reactivity of Σ-Bound Phenylacetylide

Three organometallic rhenium-based clusters con-taining phenylacetylide ligands, [Re6Se8(PEt3)5(C-C-Ph)]-(SbF6) specialIntscript and cis-and trans-[Re6Se8(PEt3)4(C-C-Ph)2] (2 and 3), were synthesized and fully characterized including single-crystal X-ray diffraction analyses. Reactivity studies of 1 show that reaction with electrophilic reagents does not result in the formation of the vinylidene species as predicted; instead, elimination of the acetylide moiety is observed. Products isolated from these reaction s, including the met hyl sulfate complex, [Re6Se8(PEt3)5(OSO3Me)](SbF6) specialIntscript have been characterized along with those obtained from the [2 + 2] cycloadditions of 1 with tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane. The relative reactivities of the electrophilic agents utilized are compared. Preliminary computational studies reveal useful information about the nature of the [Re6Se8]2+-acetylide bond and aid in our understanding of the reactivity associated with this cluster complex.

Automated summary

Three organometallic rhenium-based clusters containing phenylacetylide ligands were synthesized and characterized. Reactivity studies showed that the formation of vinylidene species did not occur as predicted, but instead the elimination of the acetylide moiety was observed. The isolated reaction products were characterized, and the relative reactivities of the electrophilic agents were compared. Computational studies provided useful information about the nature of the [Re6Se8]2+-acetylide bond and aided in understanding the reactivity of this cluster complex.