Ruthenium complexes thiolates

Another method for reductive dimerization has been developed in hy-drosilylation. NiCl2-SEt2 is an effective catalyst in silylative dimerization of aromatic aldehydes with a hydrosilane (Scheme 12) [40]. A catalytic thiolate-bridged diruthenium complex [Cp RuCl(/ 2-SPrI)2RuCp ][OTf] also induces the conversion to 1,2-diaryl-1,2-disiloxyethane [41]. A dinuclear (siloxyben-zyl)ruthenium complex is considered to be formed, and the homolytic Ru - C bond fission leads to the siloxybenzyl radicals, which couple to the coupling product 14. 

Combination of assembled microcell [134] or Au chip electrode [132] with a positive-intrinsic-negative (PIN) photodiode detector lead to advancement in the miniaturization of ECL instrumentation for DNA quantification. Though, noise level and sensitivity of sihcon PIN diode are less sensitive than a PMT [134]. A highly sensitive DNA biosensor, fabricated by self-assembling the ECL probe of thiolated hairpin DNA tagged with ruthenium complex on the surface of a gold electrode works on a switch-off mode and ECL intensity decreases with an increase of the concentration of target DNA, and a detection limit of 9 x 10 M... 

Borylated pyrrole 88 was prepared by Oestreich by treatment of the corresponding pyrrole with pinacolborane and a ruthenium(II) thiolate complex. The direct synthesis of 88 promises to find wide utility in medicinal chemistry and was applied to a variety of substituted indoles (13JA10978). N-Methylpyrrole was directly arylated at room temperature by photoredox catalysis with diaryliodonium salts to furnish 89 in 84% yield (13SL507). 

The catalytic use of thiolate-bridged diruthenium complexes was reported in 2000 by Hidai et al. in which p-tol-uenethiol 361 underwent a regioselective reaction with a propargyl alcohol 360 without forming an allenic by-product (Scheme 46.42). ° The involvement of (o-propargyl) ruthenium complexes 363 was suggested based on the... 

Fig. 22. Remarkable activation-by-ligand-oxidation pathways for the reaction of ruthenium-arenes with thiolates. (a) Reaction of [Ru (r 6-bip)(en)(OH2)]+ with GSH (b) direct synthesis of ruthenium-arene sulfenato complexes (c) the air-stable thiolato complexes are oxidized in the presence of the antioxidant GSH.

The nature of the bridging thiolate ligands or the replacement of a terminal chloride ligand by water did not have much effect on the catalytic activity, complexes 105b-d and 106a,b being also operative in these transformations. In contrast, conventional monometallic ruthenium derivatives, as well as diruthenium complexes having no Ru-Ru bond, did not work at all. 

Propargylic alcohols bearing a terminal triple bond react with electron-rich aromatic compounds in the presence of thiolate-bridged diruthenium complexes to give the propargylated aromatic compounds.30 l-Phenylprop-2-yn-l-ol, for example, reacts with 2-methylfuran to form (15). Intramolecular examples of the reaction were also reported. The process is believed to involve electrophilic attack by the ruthenium-stabilized propargyl cation. 

Hu W, Luo Q, Ma X, Wu K, Liu J, Chen Y, Xiong S, Wang J, Sadler PJ, Wang F (2009) Arene control over thiolate to sulfinate oxidation in albumin by organometallic ruthenium anticancer complexes. Chem Eur J 15 6586-6594... 

Thiolate-bridged diruthenium complexes such as Cp RuCl(p2-SR)2RuCp Cl catalyze the propargylic substitution reaction of propargylic alcohol derivatives with various carbon-centered nucleophiles [118-120]. Ketones [119] (Eq. 88), aromatic compounds [120] (Eq. 89), or alkenes thus selectively afford the corresponding propargylated products with C-C bond formation. An allenylidene intermediate is proposed in these reactions. They are detailed in the chapter Ruthenium Vinylidenes and Allenylidenes in Catalysis of this volume. 

The double phosphinylation of propargylic alcohols with diphenylphos-phine oxide to form 2,3-bis(diphenylphosphinyl)-1-propenes is catalyzed by a thiolate-bridged diruthenium complex (Scheme 28) [69]. It has been shown that the reaction proceeds via three ruthenium-catalyzed transformations propargylation of the phosphine oxide, alkyne to allene isomerization, and addition of phosphine oxide to the allene structure. 

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