A binuclear guanidinate yttrium carbyne complex: unique reactivity toward unsaturated C–N, C–O and C–S bonds

A guanidinato-stabilized binuclear yttrium carbyne complex [(PhCH(2))(2)NC(NC(6)H(3)(i)Pr(2)-2,6)(2)](2)Y(2)(μ(2)-Me)(AlMe(3))(2)(μ(4)-CH) (1) was synthesized via C–H bond activation and its versatile reactivities were investigated. Complex 1 underwent σ-bond metathesis with PhSSPh and nucleophilic addition with PhCN to form the corresponding yttrium thiolate complex 3 and aza–allyl complex 4 respectively. Additionally, the rare yttrium carbide complex 5 was also prepared by treatment of complex 1 with S(8). Interestingly, in the reaction with PhNCS, the C[double bond, length as m-dash]S double bond was cleaved, followed by C–H bond activation to give the yttrium sulfide complex 7 with a ketenimine dianion ligand. Unexpectedly, the reaction of complex 1 with CO (1 atm) resulted in deoxygenative coupling of CO, to afford mono- or dioxo-yttrium complexes at different temperatures. The mechanism of the possible formation processes of complexes 3 and 9 was elucidated by DFT calculations.