Cluster compounds, electrochemistry

This mechanism can be found in the electrochemistry of compounds with two or more oxidation states. Oxidation of the tantalum cluster compound Ta6Br122+ is a typical case [5] ... 

The electrochemistry of cluster compounds is still an underdeveloped area (75,76). A recent study has shown interesting differences in the redox behaviors of the isostructural compounds Fe4(CO),2Au2(PPh3)2BH and Fe4(CO),2Au2(AsPh3)2BH. Each undergoes a one-electron reduction and oxidation, but only the phosphine derivative can be oxidized further to the dication. All electrochemically generated species are short lived (71). 

Having reviewed the electrochemistry of homo- [10] and heterometal-sulfur clusters [11], we have directed our attention to metal-carbonyl clusters. The stereochemical effects associated with the redox behaviour of homonuclear complexes have been recently reported [13]. In this review, those of heteronu-clear compounds are discussed. Cluster compounds are classified according to their nuclearity as well as their geometrical assembly. Main-group elements at the borderline between metals and non-metals are treated as metallic elements. Occasionally, polynuclear compounds having no metal-metal bonds (and, as such, are not classifiable as clusters) are also included. 

Iron-sulfur cluster compounds, 1203 dinuclear, 235 electrochemistry, 236 hexanuclear, 241 mononuclear, 235 tetranuclear, 238 trinuclear, 237 Isomerization iridium catalysts, 1158... 

M. J. Hostetler, S. J. Green, J. J. Stokes, and R. W. Murray, Monolayers in three dimensions synthesis and electrochemistry of o>-functionalized alkanethiolate-stabilized gold cluster compounds, /. Am. Chem. Soc. 118,4212-4213(1996). 

The result of refluxing [Os3(CO)io( i3-Fc-C = C-C = C-Fc)] with H2O in THF was three new cluster compounds in which the bridging butadiene ligand had been partially hydrogenated. The crystal structures and electrochemistry of these new compounds was presented. A series of compounds of which 172 is representative have been prepared and electrochemical studies showed inter-metal communication. " Compound 173 has been synthesised and fully characterised. Its utility in hydrogenation reactions was also presented. Compound 174 has been shown to deliver ees of up to 86% in enantioselective isomerisation of allyl alcohols.49 ... 

Hostetler, M.J., Green, S.J., Stokes, J.J. and Murray, R.W. (1996) Monolayers in three dimensions synthesis and electrochemistry of d-functionalized alkanethiolate-stabilized gold cluster compounds. Journal of the American Chemical Society, 118, 4212-13. 

Although recent reviews of metal-carborane electrochemistry (37, 38) obviate the need to discuss multimetallic carborane clusters here, it seems appropriate to mention the results of studies on triple-decker sandwich compounds. The only structurally confirmed (39) all-hydrocarbon tripledecker, [Ni2Cp3] (18), has apparently not been investigated electro-chemically, but carborane analogues containing two or three boron atoms... 

Retaining the theme of metal carbonyl clusters, capping considerations in transition-metal clusters have been discussed with reference to [Sb2Co4(CX))] g( A-CX))], and [Bi2Co4(CO)jQ( i-CO)]" 28. An infrared spectroscopic study of the formation of carbonyl rhodium clusters on a rhodium electrode produced by oxidation reduction cycles in acidic solution 2 has also been published. Electrochemistry with ruthenium carbonyls >21 osmium carbonyls 2 jg also reported. Muon spin rotation in a metal-cluster carbonyl compound has been communicated and, lastly, a proton spin-lattice NMR relaxation study of hydride carbonyl clusters has been reported. This provides a method for determining distances involving hydrido ligands... 

An investigation of the electrochemistry of the cluster ( (hrab)3Nb3Cl6] has revealed three quasi-reversible oxidation processes. It is proposed that all the compounds generated retain the trimeric unit.232 ijhg reduction of Cp2ZrCl2 with Mg(anthracene) has been reported to give a zirconium anthracene complex. 

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