SYNTHESIS AND REACTIVITY OF THE FIRST STABLE CHROMIUM(VI) ALKYLIDENE COMPLEXES

The chromium(VI) dialkyl complex [Cr(NC6H3Pr2i-2,6)(2)(CH(2)CMe(3))(2) ] readily eliminates CMe(4) in room-temperature hydrocarbon and ether solutions to generate the hexavalent alkylidene species [Cr(NC6H3Pr2i- 2,6)(2)(=CMe(3))] which can be trapped in the presence of strong donor molecules to give the first stable hexavalent chromium alkylidene com plexes [Cr(NC6H3Pr2i-2.6)(2)(=CHCMe(3))(L)] (L = thf, PMe(3)); in arom atic hydrocarbon solutions, the products obtained are those arising fr om C-H activation across the chromium-carbon double bond.