Ruthenium complexes carbon donors

Paetzold and Backvall [27] have reported the DKR of a variety of primary amines using an analog of the ruthenium complex 1 as the racemization catalyst and isopropyl acetate as the acyl donor, in the presence of sodium carbonate at 90 °C (Fig. 9.17). Apparently, the function of the latter was to neutralize traces of acid, e.g. originating from the acyl donor, which would deactivate the ruthenium catalyst. 

Hydrogenation of Carbon-Carbon Multiple Bonds. There are a number of ruthenium complexes that can catalyze hydrogenation of various substrates, either through reduction with molecular hydrogen, or transfer reactions from a hydrogen donor. Generally, the available substrates for hydrogenation include the double bonds present in nitro compounds, alkenes, aldehydes, ketones, and other carboxylic acid derivatives (4). 

A significant research effort has been devoted to the design and application of various supramolecular self-assembled systems in photoelectrochemical solar cells. Fullerenes, fullerene derivatives, and carbon nanotubes are typically used as electron acceptor components of such systems. Porphyrins, phthalocyanines, ruthenium complexes, conjugated oligomers, and polymers are applied as electron donor counterparts. 

Backvall and coworkers have also developed a practical method for the chemo-enz3unatic DKR of primary amines using dibenzyl carbonate as acyl donor, combining the use of CAL-B and the ruthenium complex mentioned above in toluene at 90 °C for the production of enantioenriched (R)-carbamates (60-95% )deld, 90-99% ee Table 9.6) [243]. The main advantage of this method is that the benzyloxycarbonyl group (Cbz) can be easily removed by hydrogenolytic cleavage without any loss of the carbamate optical purity (compoimd in entry 1 of Table 9.6) [244]. 

RuCl2(PPh3)2 reacts with 4-R2P-dibenzothiophene (R = Ph, p-Tol) and forms 303, in which the dibenzothiophene ligand is coordinated to ruthenium via the phosphorus and sulfur atoms [84JA5379, 87JOM(318)409]. The donor ability of the sulfur atom is relatively weak. Complex 303 (R = Ph) is able to add carbon monoxide and yield the monocarbonyl adduct. 

The sensor for the measurement of high levels of CO2 in gas phase was developed, as well90. It was based on fluorescence resonance energy transfer between 0 long-lifetime ruthenium polypyridyl complex and the pH-active disazo dye Sudan III. The donor luminophore and the acceptor dye were both immobilized in a hydrophobic silica sol-gel/ethyl cellulose hybrid matrix. The sensor exhibited a fast and reversible response to carbon dioxide over a wide range of concentrations. 

The complexed arene rings in tethered complexes of ruthenium(II) are close to planar, though the ipso-carbon atom is often pulled slightly towards the metal atom. In the phosphine complexes, the Ru-C(arene) distances trans to the P-donor (2.22-2.29 A) are significantly greater than those trans to the Ru-Cl bonds (2.15-2.25 A). This feature is also evident in non-tethered complexes of the type [RuCl2(r 6-arene)(PR3)] and can be attributed to the higher trans-influence of PR3 relative to that of Cl-.88... 

The ruthenium(II) complexes interact with CCI4 and are oxidized in the process to become Ru(III) and radicals CCl3 that add to molecules of methyl methacrylate. The polymerization proceeds via repetitive additions of methyl methacrylate molecules to the radical species that are repeatedly generated from the covalent species with carbon-halogen terminal groups [226]. Suwamoto also reported [226] that addition of a halogen donor, PhsC-Cl aids the shift of the equilibrium balance to dormant species. The reaction of polymerization can be illustrated as follows ... 

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