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

Abstract

A guanidinato-stabilized binuclear yttrium carbyne complex [(PhCH₂)₂NC(NC₆H₃ⁱPr₂-2,6)₂]₂Y₂(μ₂-Me)(AlMe₃)₂(μ₄-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 S₈. Interestingly, in the reaction with PhNCS, the CS 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.