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

Abstract

Reactions of Ru(C{triple bond, long}CPh)(PPh3)2Cp with (NC)2C{double bond, long}CR1R2 (R1 = H, R2 = C{triple bond, long}CSiPri3 8; R1 = R2 = C{triple bond, long}CPh 9) have given η3-butadienyl complexes Ru{η3-C[{double bond, long}C(CN)2]CPh{double bond, long}CR1R2}(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, long}C(CN)2]CPh{double bond, long}CHC{triple bond, long}C[MLn]}(PPh3)Cp [MLn = Ru(dppe)Cp 19, Au(PPh3) 20]. Reactions between 8 and Ru(C{triple bond, long}CC{triple bond, long}CR)(PP)Cp [PP = (PPh3)2, R = Ph, SiMe3, SiPri3; PP = dppe, R = Ph] gave η1-dienynyl complexes Ru{C{triple bond, long}CC[{double bond, long}C(CN)2]CR{double bond, long}CH[C{triple bond, long}C(SiPri3)]}(PP)Cp (15-18), respectively, in reactions not involving phosphine ligand displacement. The phthalodinitrile C6H(C{triple bond, long}CSiMe3)(CN)2(NH2)(SiMe3) 10 was obtained serendipitously from (Me3SiC{triple bond, long}C)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. © 2008 Elsevier B.V. All rights reserved.