Light-Driven Ring Slippage in [Re(η 7 -C 7 H 7 )(η 5 -C 7 H 9 )] + and the Inertness of Its Technetium Homologue.

Here, we present the light-driven reactions of [Re(η 7 -C 7 H 7 )(η 5 -C 7 H 9 )] + ( 1 + ) with nitriles, phosphines, and isocyanides, which are added to 1 + via a ring slippage of the tropylium cation from η 7 to η 3 , forming [Re(η 3 -C 7 H 7 )(η 5 -C 7 H 9 )(L) 2 ] + (L= acetonitrile 2 + ; 2-phenylacetonitrile 3 + ; 1,3,5-triaza-5-phosphoadamantane (PTA) 4 + ; tert -butyl isocyanide 6 + ; benzyl isocyanide 7 + ) and [Re(η 3 -C 7 H 7 )(η 5 -C 7 H 9 )(L)] + with L = (ethane-1,2-diyl)bis(diphenylphosphane) (dppe) 5 + . To compare the reactivities of rhenium and technetium, we also investigated the synthesis of [ 99 Tc(η 6 -C 10 H 8 ) 2 ] + , its substitution of naphthalene with cyclohepta-1,3,5-triene to obtain [ 99 Tc(η 7 -C 7 H 7 )(η 5 -C 7 H 9 )] + , and its reactivity (or lack thereof) with light.