Ruthenium nitrogen containing

The first dinitrogen complex, characterized in 1965, resulted From the reduction of commercial ruthenium trichloride [containing some Ru(lV)] by hydrazine hydrate. The pentuammine(dinitrogen)ruthenium(Il) cation that formed could be isolated in a variety of salts.50 Soon other methods were found to synthesize the complex, such as the decomposition of the pentaammineazido complex, [Ru NH3)3N,Jj+, and even direct reaction with nitrogen gas ... 

Whereas the catalytic hydrosilylation of alkynes was one of the first methods of controlled reduction and functionalization of alkynes, the ruthenium-catalyzed hydroamination of alkynes has emerged only recently, but represents a potential for the selective access to amines and nitrogen-containing heterocydes. It is also noteworthy that, in parallel, the ruthenium activation of inert C-H bonds allowing alkyne insertion and C-C bond formation also represents innovative aspects that warrant future development. Among catalytic additions to alkynes for the production of useful products, the next decade will clearly witness an increasing role for ruthenium-vinylidenes in activation processes, and also for the development of ruthenium-catalyzed hydroamination and C-H bond activation. 

Schmidt B. Ruthenium-catalyzed cyclizations more than just olefin metathesis Angew. Chem. Int. Ed. 2003 42 4996-4999. Vemall AJ, Abell AD. Cross metathesis of nitrogen-containing systems. Aldrichim. Acta 2003 36 93-105. 

A range of metals and metal oxides catalyze the reduction of NO. The most successful reducing agent is synthesis gas since the catalytic process is relatively fast 184), unlike the catalyzed decomposition of NO to N2 and O2. The observed nitrogen-containing products depend on the catalytic system used Pd- and Pt-based catalysts convert NO to NH3 184) whereas iridium and ruthenium systems minimize ammonia production and convert nitric oxide to dinitrogen. 

This strategy has been extended to form a four-helix bundle metalloprotein. The oligopeptide was functionalized with a pyridine moiety to allow four of the peptides to bind to a metal ion. Ruthenium(II) was chosen as the metal ion because it is known to have a strong affinity for nitrogen-containing aromatic heterocycles. When the peptide was allowed to complex with ruthenium(II), a four-helix bundle metalloprotein was formed. Circular dichroism revealed that the complex exhibited >90% a-helicity with no dependence on concentration [76]. 

In ruthenium-catalyzed direct arylations, the directing abilities of 2-oxazolinyl, 2-imidazolinyl, and 1-pyrazolyl groups turned out to be comparable to those observed for 2-pyridyl substituents [60]. As a consequence, a number of nitrogen-containing five-membered heterocycles have been employed as directing groups in intermo-lecular ortho-arylation reactions [60, 62], As an example, the 2-aryloxazoline 76 was... 

The enantio- and diastereoselective synthesis of the nitrogen-containing heterocyclic compounds 612 was achieved by a one-pot reaction via the ruthenium-catalyzed enyne coupling of 608 with 609 followed by the palladium-catalyzed asymmetric C—N bond formation (Scheme 186).264a The enyne coupling reaction proceeds through formation of the ruthenacycle 611 followed by -elimination—reductive elimination. 

Reviews have appeared of light-induced electron-transfer reactions of ruthenium complexes containing nitrogen heterocycles. 

RCM was also successfully applied for the synthesis of wide range of nitrogen-containing heterocycles. Pioneered by Dixneuf and Osipov," this approach was first applied for the synthesis of azepines 68 (Fig. 10.29). RCM reaction of 4-azanona-dienes-1,8 catalyzed by Grubs-type ruthenium catalysts results in high-yield formation of the corresponding azepines. 

It should be noted that related coupling reactions have been developed for aromatic compounds having carbonyl- and nitrogen-containing functional groups with unsaturated compounds, especially by using ruthenium and rhodium catalysts, which involve precoordination of the neutral functional groups followed by ortho-C-H activation [7,9,153,154]. 

Moreover, the radiation from this Isotope allows Its use In presently available radlosclntlgraphlc equipment. A series of precursor complexes Involving Ru(II) and Bu(III), which could be used to coordinate a range of nitrogen-containing biochemical ligands and macromolecules such as proteins and nucleic acids, seems possible. Finally, Improvement of the tumor localization, already exhibited by some ruthenium complexes, based on the elevated Ru(IT)/Ru(III) ratios hypothesized to occur In tumor relative to normal tissue may make available a new class of tumor-lmaglng pharmaceuticals. 

Some platinum metals, especially ruthenium but also rhenium, osmium, and iridium, form luminescent complexes with nitrogen-containing ligands, e.g., 2,2 -bipyridine (bpy). These complexes may participate in redox reactions with concomitant chemiluminescence in three different ways. 

In addition to palladium catalysts, ruthenium catalysts were applied in carbonylative C-H activation reactions as well. Moore and colleagues described the first ruthenium-catalyzed carbonylative C-H activation reaction in 1992 [52], Orf/io-acylation of pyridine and other nitrogen-containing aromatic compounds can be carried out with olefins and CO, using Ru3(CO)i2 as the catalyst (Scheme 6.16). Interestingly, internal olefins, such as cis- and frawi-2-hexene, yield the same linear/branched product ratio as terminal olefins. 

---