The synthesis of several cationic Fe(IV) alkylidenes was accomplished via the utilization of tetra- and tri-dentate chelate ligands. Related neutral Fe(IV) alkylidenes were prepared via nucleophilic attack at the imine of cationic [mer-{k-C,N,C-(C6H4-yl-2-CH=N(2-C6H4-C(iPr)=}Fe(PMe3)3][B(3,5-CF3-C6H3)4] to afford mer-{k-C,N,C-(C6H4-yl-2-CH(R)N(2-C6H4-C(iPr)=}Fe{trans-(PMe3)2}N2 (R = Me, Bn, 2-picolyl). MeMgCl displaced PMe3 to give mer-{k-C,N,C-(C6H4-yl-2-CH=N(2-C6H4-C(iPr)=}Fe{trans-(PMe3)2}CH3. Related neutral tetradentate complexes, {k-C,N,C,P-(C6H4-yl-2-CH(CH2PRR')N(2-C6H4-C(iPr)=}Fe(PMe3)2 (PRR' = PMe2, PMePh, PPh2) were prepared via addition of Me2PCH2Li, MePhPCH2Li, and Ph2PCH2Li to the cationic complex. While none of these complexes are active for olefin metathesis, efforts to extend these and other systems toward catalytically active species will be discussed.

Approaches to the synthesis of Fe(IV) alkylidenes

251st National Meeting (2016)

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