Reactions of cyano(alkynyl)ethenes with some alkynyl- and diynyl-ruthenium complexes

Reactions of Ru(Ctriple bond; length of mdashCPh)(PPh3)2Cp with (NC)2Cdouble bond; length as m-dashCR1R2 (R1 = H, R2 = Ctriple bond; length of mdashCSiPri3 8; R1 = R2 = Ctriple bond; length of mdashCPh 9) have given η3-butadienyl complexes Ru{η3-C[double bond; length as m-dashC(CN)2]CPhdouble bond; length as m-dashCR1R2}(PPh3)Cp (11, 12), respectively, by formal [2 + 2]-cycloaddition of the alkynyl and alkene, followed by ring-opening of the resulting cyclobutenyl (not detected) and displacement of a PPh3 ligand. Deprotection (tbaf) of 11 and subsequent reactions with RuCl(dppe)Cp and AuCl(PPh3) afforded binuclear derivatives Ru{η3-C[double bond; length as m-dashC(CN)2]CPhdouble bond; length as m-dashCHCtriple bond; length of mdashC[MLn]}(PPh3)Cp [MLn = Ru(dppe)Cp 19, Au(PPh3) 20]. Reactions between 8 and Ru(Ctriple bond; length of mdashCCtriple bond; length of mdashCR)(PP)Cp [PP = (PPh3)2, R = Ph, SiMe3, SiPri3; PP = dppe, R = Ph] gave η1-dienynyl complexes Ru{Ctriple bond; length of mdashCC[double bond; length as m-dashC(CN)2]CRdouble bond; length as m-dashCH[Ctriple bond; length of mdashC(SiPri3)]}(PP)Cp (15–18), respectively, in reactions not involving phosphine ligand displacement. The phthalodinitrile C6H(Ctriple bond; length of mdashCSiMe3)(CN)2(NH2)(SiMe3) 10 was obtained serendipitously from (Me3SiCtriple bond; length of mdashC)2CO and CH2(CN)2, as shown by an XRD structure determination. The XRD structures of precursor 7 and adducts 11, 12 and 17 are also reported.