Reactivities of [Re(η 6 -C 6 H 6 )(η 6 -C 10 H 8 )] + and [Re(η 6 -C 10 H 8 ) 2 ] + with Cyclic, Nonaromatic Polyenes

High Resolution Image Download MS PowerPoint Slide The synthesis of sandwich complexes of rhenium is essentially limited to compounds of the type [Re(η 6 -arene) 2 ] + via the Fischer–Hafner approach. This strategy is not compatible with arenes carrying functional groups or nonaromatic polyenes in particular. As reported, naphthalene in [Re(η 6 -C 6 H 6 )(η 6 -C 10 H 8 )] + and in [Re(η 6 -C 10 H 8 ) 2 ] + are exchanged by functionalized arenes in low to medium yields. In contrast, cyclic nonaromatic polyenes exchange naphthalene straight and in good to very good yields. We report herein on the syntheses of rhenium sandwich complexes with seven- and eight-membered rings bearing multiple double bonds such as cyclohepta-1,3,5-triene, tropone, or cycloocta-1,3,5-triene. Starting from [Re(η 6 -C 6 H 6 )(η 6 -C 10 H 8 )] + and [Re(η 6 -C 10 H 8 ) 2 ] +, sandwich complexes such as [Re(η 7 -C 7 H 7 )(η 5 -C 7 H 9 )] + and others are obtained and fully characterized in high yields (70–86%). These nonaromatic sandwich complexes form highly stable compounds.