Ruthenium ammine complexes

Ruthenium Red. A characteristic of ruthenium complex ammine chemistry is the formation of highly colored red or brown species usually referred to as ruthenium reds. Thus, if commercial ruthenium chloride is treated with ammonia in air for several days, a red solution is obtained. Alternatively, if Ru111 chloro complexes are reduced by refluxing ethanol and the resulting solution is treated with ammonia and exposed to air at 90° with addition of more ammonia at intervals, again a red solution is obtained. Crystallization of the solutions gives ruthenium red. 

Historically, the most important ruthenium(II) ammine species is [Ru(NH3)5N2]2+, the first stable dinitrogen complex to be isolated (1965). It was initially obtained by refluxing RuC13 in hydrazine solution (but many... 

Table 19.1 Calculated values of k, rd and for various ammine ruthenium complexes as a water oxidation catalyst incorporated into Nation membrane...

Coe, B. J., Jones, L. A., Harris, J. A., et al., Syntheses and spectroscopic and quadratic nonlinear optical properties of extended dipolar complexes with ruthenium(II) ammine electron donor and N-methylpyridinium acceptor groups. J. Am. 

Ruthenium(II) ammine complexes can be readily prepared under mild conditions by reacting the aquo complex with neutral ligand followed by air oxidation ... 

Some accounts on the redox-induced switching of hyperpolarisabilities utilised penta-ammine ruthenium complexes bearing substituted 4,4 -bipyri-dinium coligands. The intense bipyridinium Ru LMCT band at 580 to 636 nm bleaches upon reduction of the metal centre, thus switching off their quadratic NLO response. The oxidation of the ferrocene donor in an ethenyl-linked ferrocene-nitrothiophene dyad likewise results in a decrease of the quadratic NLO response by about one order in magnitude. Oxidation-state-dependent quadratic NLO performance has also been noted by Lapinte and coworkers who compared the complexes Cp (dppe)Fe—C=CPh, Cp (dppe)Fe-C=C- 2(p-C6H4-l,4), Cp (dppe)Fe-C=C- 2(g-C6H4-l,3),... 

Coe, B.J., Harris, J.A., Asselberghs, I., Persoons, A., Jeffery, J.C., Rees, L.H., Gelbrich, T., Hursthouse, M.B. Tuning of charge-transfer absorption and molecular quadratic nonhnear optical properties in ruthenium(II) ammine complexes. J. Chem. Soc., Dalton Trans. 3617-3625 (1999)... 

Ruthenium(II) ammines can also give rise to Czv symmetric 2D dipolar chromophores featuring two cis pyridyl-pyridinium ligands (e.g. 30, Figure 1.14). Such V-shaped complexes are interesting and unusual because they have a significant off-diagonal tensor component /S yy in addition to the classical component. They display two MLCT bands in the visible, and TD-DFT calculations have shown that the lowest... 

It is again most convenient to consider such compounds together. Ruthenium(ll) Ammines.13 There is an exceedingly wide range of ruthenium ammine complexes and they are of special interest because of the ready formation of nitrogen (N2) complexes. 

Because it is affected by the interaction of a redox molecule and a matrix, charge transfer can involve both physical diffusion and charge hopping. A typical example is an oxo-bridged trinuclear ammine ruthenium complex called Ru-red 6. 

The quantum yield for ammonia loss from [Ru(NH3)4(dpp)] " and its binu-clear analog [(H3N)4Ru(dpp)Ru(NH3)4], where dpp = 2,3-bis(2-pyridyl) pyrazine (39), is wavelength-dependent and low. This behavior is typical of ruthenium(II) ammine complexes in which the lowest excited state is MLCT. ... 

Interaction of nitric oxide with ruthenium(lll) ammine and terpyridine complexes... 

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