Chemistry of ruthenium complexes with hexamethylbenzene and butadienesulfonyl ligands: Synthesis and reactivity toward phosphites and silver triflate

Abstract

The addition reaction of (η6-C6Me6)Ru(Cl)(1-2,5-η-CH2CHCHCHSO2) (1) with one equivalent of P(OMe)3 or P(OPh)3 led to the formation of the corresponding compounds (η6-C6Me6)Ru(Cl)(5-η-SO2CHCHCHCH2)(P(OR)3) (R = Me, 4a; Ph, 4b). After 4a and 4b lose AgCl in presence of AgOTf, the immediate coordination of the terminal double bond of the butadienesulfonyl ligand affords the corresponding cationic complexes [(η6-C6Me6)Ru(1-2,5-η-CH2CHCHCHSO2)(P(OR)3]OTf (R = Me, 5a; Ph, 5b). The alternative metathesis reaction between dichlorido compounds (η6-C6Me6)Ru(Cl)2(P(OR)3) (R = Me, 2a, Ph, 2b) and the potassium butadiene sulfinate K(SO2CHCHCHCH2) (3) was only successful in the case of 4a. The 1H, 13C{1H} NMR data of 4a and 4b are consistent with a butadienesulfonyl ligand coordinated preferentially as an S conformer, while only traces of the thermodynamic W conformer have been seen in solution for 4a. The single crystal analysis of neutral 4a and cationic 5b reveals the presence of the butadienesulfonyl ligand binding to ruthenium exclusively through the sulfur atom in the case of 4a, while in 5b, the coordination of the terminal double bond to the metal center also occurs. A comparative study of the influence of the phosphite and phosphine ligands on analogue isoelectronic molecular structures with the η6-C6Me6 and η5-C5Me5 anchored ligands is analyzed. The high stability of 2a and 2b is corroborated and compared to the phosphine analogues. The single crystal of 2b is also discussed.