Molybdenum Chalcogenobenzimidato Complexes: Radical Synthesis and Nitrile Extrusion via β-EPh (E = S, Se, and Te) Elimination

Molybdenum chalcogenobenzimidates of formula (Ph[PhE]CN)Mo(N[t-Bu]Ar)3 (Ar = 3,5-C6H3Me2) have been obtained by
treatment of Mo(N[t-Bu]Ar)3 sequentially with benzonitrile and 0.5
equiv of PhEEPh (E = S, Se, and Te). Molecular structure
determinations have been carried out for the S and Se variants.
The Te variant extrudes PhCN forming structurally characterized
(PhTe)Mo(N[t-Bu]Ar)3 with facility assessed via stopped-flow kinetic
measurements, while the Se and S analogues exhibit increasing
stability. Quantum chemical calculations and solution calorimetry
have been employed as an aid to interpretation of the PhCN
extrusion reaction.