Ruthenium complexes tris

Ruthenium Complexes. Tris(2,2 -bipyridyl-4,4 -diphenyl) ruthenium-(II), tris(2,2 -bip5uidyI-4,4 -dimethyI) ruthenium(II), and tris(I,IO-phenan-throline) ruthenium(II) are red fluorescent dyes. ° They can be incorporated in a PVK a matrix as a hole-transporting material and PBD as electron transporting material. Bright red is emitted when the concentration of the dye in the PVK matrix is appropriately adjusted in a LED device with the layers ITO/(dyePVKPBD)/Mg/Ag. 

Ruthenium Complexes. Tris(2,2 -bipyridyl-4,4L diphenyl) ruthenium(II), tris(2,2 -bipyridyl-4,4 -... 

Maggini M, Done A, Scorrano G and Prato M 1995 Synthesis of a [60]fullerene derivative covalently linked to a ruthenium (II) tris(bipyridine) complex J. Chem. Soc., Chem. Commun. 845-6... 

Imidazole is characterized mainly by the T) (N) coordination mode, where N is the nitrogen atom of the pyridine type. The rare coordination modes are T) - (jt-) realized in the ruthenium complexes, I-ti (C,N)- in organoruthenium and organoosmium chemistry. Imidazolium salts and stable 1,3-disubsti-tuted imidazol-2-ylidenes give a vast group of mono-, bis-, and tris-carbene complexes characterized by stability and prominent catalytic activity. Benzimidazole follows the same trends. Biimidazoles and bibenzimidazoles are ligands as the neutral molecules, mono- and dianions. A variety of the coordination situations is, therefore, broad, but there are practically no deviations from the expected classical trends for the mono-, di-, and polynuclear A -complexes. 

Besides the tris ruthenium complexes, other complexes can be made (Figure 1.20), while ethylenediamine (en) complexes exist ... 

Complexation via amidinate units was found in ruthenium complexes containing tri- and pentacyclic trifluoromethylaryl-substituted quinoxalines. The complex fragment [(tbbpy)2Ru] (tbbpy = bis(4,4 -di-ferf-butyl-2,2 -bipyridine) has been employed in these compounds which have all been structurally characterized by X-ray diffraction. ... 

There are more examples of a second type in which the chirality of the metal center is the result of the coordination of polydentate ligands. The easiest case is that of octahedral complexes with at least two achiral bidentate ligands coordinated to the metal ion. The prototype complex with chirality exclusively at the metal site is the octahedral tris-diimine ruthenium complex [Ru(diimine)3 with diimine = bipyridine or phenanthroline. As shown in Fig. 2 such a complex can exist in two enantiomeric forms named A and A [6,7]. The bidentate ligands are achiral and the stereoisomery results from the hehcal chirality of the coordination and the propeller shape of the complex. The absolute configuration is related to the handness of the hehx formed by the hgands when rotated... 

We report here studies on a polymer fi1m which is formed by the thermal polymerization of a monomeric complex tris(5,5 -bis[(3-acrylvl-l-propoxy)carbonyll-2,2 -bipyridine)ruthenium(11) as its tosylate salt,I (4). Polymer films formed from I (poly-I) are insoluble in all solvents tested and possess extremely good chemical and electrochemical stability. Depending on the formal oxidation state of the ruthenium sites in poly-I the material can either act as a redox conductor or as an electronic (ohmic) conductor having a specific conductivity which is semiconductorlike in magnitude. 

Nagashima reported the hydrogenation of di-, tri- and tetranuclear ruthenium complexes bearing azulenes below 100 °C revealed that only the triruthenium compounds reacted with H2 via triruthenium dihydride intermediates.398 This indicates that there exists a reaction pathway to achieve facile activation of dihydrogen on the face of a triruthenium carbonyl moiety.399... 

Table 1 Colors (established by bulk electrolysis in acetonitrile) of the ruthenium(II) tris-bipyridyl complexes of the ligands given below, in all accessible oxidation states.15...

T. Hasegawa, T. Yonemura, K. Matsuura, and K. Kobayashi, Tris-bipyridine ruthenium complex-based glyco-clusters Amplified luminescence and enhanced lectin affinities, Tetrahedron Lett., 42 (2001) 3989-3992. 

The greater reactivity of terminal olefins compared to their more hindered di-and tri-substituted counterparts became evident in the model studies (Sect. 2.2.1) and in the total synthesis of epothilones A, B and E (Sects. 2.2.2-2.2.4). Suitably positioned disubstituted olefins can, however, participate in RCM reactions employing the molybdenum initiator 1 [19], and this is demonstrated in the total synthesis of epothilone B (5) (Sect. 2.2.3). As expected this transformation proved impossible using the ruthenium complex 3. 

Besides the electrochemical application, the (Cp )Rh(bpy)-complex 9 can also be used to reduce cofactors with hydrogen. In a recent study it was compared with ruthenium complex 13 [RuC12(TPPTS)2]2 (TPPTS tris(w-sulfonatophenyl)-phosphine Scheme 43.5). Both complexes were used to regenerate the cofactors in the reduction of 2-heptanone to (S)-2-heptanol, catalyzed by an ADH from Thermoanaerobium brockii (TfrADH) [46, 47]. The TON for both catalysts was 18. 

The inverted region in electron transfer reactions is studied for the reaction of electronically-excited ruthenium(II) tris-bipyridyl ions with various metal(III) tris-bipyridyl complexes. Numerical calculations for the diffusion-reaction equation are summarized for the case where electron transfer occurs over a range of distances. Comparison is made with the experimental data and with a simple approximation. The analysis reveals some of the factors which can cause a flattening of the In k versus AG curve in the inverted... 

As shown earlier, A,A-dimethylaniline acts as an electron donor toward the electronically excited Ru(ll) tris(dipyridyl)complex (Bock et al. 1979). Nocera s group studied the effect of salt formation on the redox interaction between the ruthenium complex and the A/,At-dimethylaniline moiety. Two different salts, depicted in Scheme 5.26, were prepared and studied (Deng et al. 1997, Kirby et al. 1997, Roberts et al. 1997). 

Some years later, at the beginning of the 1970s, first ECL system based on the luminescent transition metal complex tris(2,2 -bipyridine)ruthenium(II)-Ru (bipy)32 + -has been reported.11 It was shown that the excited state 3 Ru(bipy)32 + can be generated in aprotic media by annihilation of the reduced Ru(bipy)31 + and oxidized Ru(bipy)33 + ions. Due to many reasons (such as strong luminescence and ability to undergo reversible one-electron transfer reactions), Ru (bipy)32+ later has become the most thoroughly studied ECL active molecule. 

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