Sm(II) reduction chemistry of heteroalkynes: Stable adducts, reductive coupling, reductive C-C/C-N bond cleavage and trapping of the tert-butyl fragment with bulky nitriles, phosphaalkynes and isonitriles

摘要

Reactions of a dimetallated N,N′-dimethyl substituted porphyrinogen Sm(ii) complex with a series of t-butyl substituted heteroalkynes affords a diverse range of reactivity. The phosphaalkyne t-BuCP gives a dinuclear Sm(iii) P-P reductively coupled complex of (t-BuCPPC-t-Bu)~(2-) featuring a new μ-η~2(1,2-C,P) binding mode. In contrast, the nitrile aza analogue t-BuCN forms Sm(ii) adducts that undergo reductive C-C bond cleavage at elevated temperatures to afford a trimeric Sm(iii) cyanide (μ-CN ~-) complex. The isomeric isonitrile t-BuNC undergoes the related reductive C-N bond cleavage reactivity at milder temperatures, allowing the trapping of the tert-butyl fragment as a Sm(iii) η~2-iminoacyl (t-BuCN-t-Bu)~- complex.