Synthesis and Reactivity of Cp*Ru^II η⁶-π-Adducts of Functionalized Arenes with Useful Side Chains:  X-ray Molecular Structure of [Cp*Ru(η⁶-N-succinimidyl 3-(4-methoxyphenyl)propionate)][CF₃SO₃]

Abstract

Several novel organoruthenium complexes [Cp*Ru(η6-arene)][CF3SO3] (3, 4, 6) were prepared in which the arene unit possesses an alkyl chain terminated with carboxylic acid, ester, and activated ester functions. These compounds were fully characterized by spectroscopic methods, and in particular, the activated ester complex [Cp*Ru(η6-MeOC6H4(CH2)2COONS)][CF3SO3] (6) (NS = N-succinimidyl) was identified by X-ray analysis. The reactivity of 6 with respect to benzylamine and β-alanine ethyl ester was examined and afforded quantitatively the stable conjugates [Cp*Ru(η6-MeOC6H4CH2CH2CONHCH2Ph][CF3SO3] (7) and [Cp*Ru(η6-MeOC6H4(CH2)2CONH(CH2)2COOEt][CF3SO3] (8). Furthermore, the stability and reactivity of 6 relative to the analogous dicationic organoiridium complex [Cp*Ir(η6-MeOC6H4(CH2)2COONS)][BF4]2 (10) and the neutral metallocarbonyl derivatives of the type [L n MCpCOONS] (12−14) [L n M = Fe(CO)2Me, Mo(CO)3Me, Co(CO)2] are presented and discussed.