Cyano-bridged complexes

A number of cyano-bridged complexes are included here even though they strictly do not fall in the general family-type defined for the section. The syntheses and photophysical properties of [(NC)(bpy)2Ru(/r-NC)Cr(CN)5] and [(NC)5Cr(Ai-CI Ru(bpy)2(M-NC)Cr(CN)5] have been described. Absorption of visible light by the Ru(bpy)2 unit results in phosphorescence from the Cr(CN)g luminophore, and the results evidence fast intramolecular exchange energy transfer from the MLCT state of the Ru(bpy)2 chromophore to the doublet state of the Cr -based unit. Time-resolved resonance Raman and transient UV-vis absorption spectroscopies have been employed to investigate the MLCT excited states of [(NC)(bpy)2Ru(//-CN)Ru (bpy)2(CN)], [(NC)(bpy)2Ru(//-CN)Ru(phen)2(CN)]+, [(NC)(phen)2Ru(//-CN)Ru (bpy)2(CN)]+, [(NC)(bpy)2... 

Cyano-bridged complexes include both di- and polynuclear systems. Spectroelectrochemical studies of the oxidized and reduced forms of [(bpy)2(CN)Ru(/r-CN)Ru(C (bpy)2] have been carried out. This cation and its reduced form exhibit UV-vis spectra that are consistent with the chromophores being identical. Experimental evidence indicates that the one-electron oxidation... 

The next part of this section focuses on di- and polynuclear Ru"/Os" systems (organized according to the bridging ligands), and pertinent reviews covering multicomponent molecular arrays should be consulted. The cyano-bridged complexes [(bpy)(tpy)Ru(//-CN)Ru" (NH3)5]"+ ( = 3 or 4) have been studied. Picosecond excitation of [(bpy)(tpy)Ru-(//-CN)Ru(NH3)5] results in the observation of a transient intermediate which decays by an... 

Many analogues of the dinuclear ammines (Table 47) are known in which ammonia molecules may be considered replaced by ethylenediamine and other bidentate ligands (Table 52). The inter-relations among the complexes are similar to those in Schemes 35 and 36. There are additional examples in the review by Gamer and House302 and other bridged complexes are covered in Sections 35.4.1.1, 35.4.2.3.vi, 35.4.2.4, 35.4.2.5, 35.4.4.2, 35.4.4.10, 35.4.7.4 and 35.4.8.3. Cyano-bridged complexes are listed in Table 45. 

Haim, A. and W. K. Wilmarth Binuclear Complex Ions III. Formation of Peroxo and Cyano Bridged Complexes by Oxidation of the Pentacyano Complexes of Cobalt (II). J. Am. Chem. Soc. 83, 509 (1961). 

Figure 9.18 Variable temperatnre (4—82 K) susceptibility for ErMn [99]. (With kind permission from Springer Science+Business Media Transition Metal Chemistry The magnetochemistry of novel cyano-bridged complexes Ln(DMF)4(H20)2Mn (CN)6-H20 (Ln = Tb, Dy, Er), 26, 2001, 287-289, B. Yan, and Z. Chen.)...

A general route leading to cyano-bridged complexes is the elimination of alkali metal cyanide from alkali metal dicyano-(phthalocyaninato)transition-metal(III) complexes M [PcM(CN)2] (see Scheme 12 M =Na, K M=Cr [117], Mn [ll H, Fe [114], Co [124], Rh [127]). The same method can be used to form [PcCo(SCN)] from K[PcCo(NCS)2] [119]. 

Charge Transfer Spectroscopy of Cyano-Bridged Complexes... 

Some representative examples of optical charge transfer spectra of cyano-bridged complexes will be given in this section. Other cases will be shortly mentioned in other parts of this article, particularly in Section 4.3. 

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