Isomers of Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes

The library of molybdenum imido alkylidene N-heterocyclic carbene C6H3, 2-CF3-C6H4, 2-tBu-C6H4, 2,6-iPr2-C6H3, tBu, adamantyl, 1-phenylcyclohexyl, 1phenyl-3-methylcyclohexyl) was extended to complexes with unsymmetrical (4i) and 4b-d, 4f,g, 4i-k), 1,3-biscyclohexylimidazol-2-ylidene (ICy, 4h, 4l-n), and 1,3,4triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene (TPT, 4a, 4e, 4o) complexes were synthesized. Substitution of one triflate in the molybdenum imido alkylidene NHC bistriflate compounds with an alkoxide or a phenoxide afforded complexes Mo(NG)(CHCMe2R1)(OTf)(OR2)(NHC) (5a-i) and was confirmed to proceed via a selective replacement of one specific triflate. The careful analysis of NMR and single-crystal X-ray data allowed for the determination of solution and solid-state structures. Cis- and trans-OTf isomers of IMes complexes with alkyl-substituted imido ligands, rotamers of TPT-ligated complexes, and syn-/anti-isomers and diastereomers were identified.

Automated summary

This article presents the extension of a library of molybdenum imido alkylidene N-heterocyclic carbene complexes with unsymmetrical ligands. Substitution of one triflate in these complexes with an alkoxide or a phenoxide led to the synthesis of new complexes with modified ligands. The structures of these complexes were analyzed using NMR and X-ray data.