Arene−Ruthenium Complexes of an Acyclic Thiolate−Thioether and Tridentate Thioether Derivatives Resulting from Ring-Closure Reactions

The reaction of [(η6-arene)RuCl2]2 (arene = C6Me6, 1,4-MeC6H4CHMe2) with a large excess of the dianion of
bis(2-mercaptoethyl) sulfide, (HSCH2CH2)2S, obtained from deprotonation of the dithiol with freshly prepared NaOMe,
gives the deep red, monomeric complexes [(η6-arene)Ru(η3-C4H8S3)] (arene = C6Me6 (5), 1,4-MeC6H4CHMe2 (6))
in which the dianion is bound to the metal atom through one thioether and two thiolate sulfur atoms. Complex 5
reacts with [(η6-C6Me6)RuCl2]2 (4) in a 2:1 mole ratio to give a quantitative yield of the chloride salt of a binuclear
cation [{(η6-C6Me6)Ru}2Cl(μ2-η2:η3-C4H8S3)]+ (7) in which the thiolate sulfur atoms of the [(η6-C6Me6)Ru(η3-C4H8S3)]
group bridge to a (η6-C6Me6)RuCl unit. This compound is also obtained directly from the reaction of 4 with the
dithiolate, if the Ru dimer is used in large excess. The binuclear complex [{(η6-C6Me6)Ru}2(MeCN)(μ2-η2:η3-C4H8S3)](PF6)2·MeCN, (9)(PF6)2·MeCN, is obtained by treatment of (7)Cl with NH4PF6 in acetonitrile. Protonation
of 5 with HCl gave the mono- and diprotonated derivatives viz. [(η6-C6Me6)Ru(η3-C4H9S3)]Cl, (8)Cl, and [(η6-C6Me6)Ru(η3-C4H10S3)]Cl2, (10)Cl2, respectively. The reaction of 5 with methyl iodide gives both the mono- and di-S-methylated derivatives. Treatment of 5 with dibromoalkanes, Br(CH2)nBr (n = 1−5), effects ring closure to give
the (η6-C6Me6)Ru dications containing the trithia mesocyclic zS3 (z = 8−12) ligands, isolated as their PF6 salts.
The X-ray crystal structures of 5, 6, the solvates of (7)Cl and (9)(PF6)2, and the trithia mesocyclic Ru complexes
(η6-C6Me6)Ru(zS3)(PF6)2 (z = 8−11) are reported.