Pentanuclear vanadium clusters

Figure 53. (a) The pentanuclear vanadium cluster embedded in the structure of [Mc2NH2]K4... 

Last but not least, mention should be made of the use of redox active organometallic clusters for the formation of CT complex. An early example was reported by Eisenberg, Miller and co-workers who exploited the trinuclear niobium cluster [Nb3(/i-Cl)6(>7 -C6Me6)3] and prepared the [TCNQ] salt, upon oxidation to the dicationic form. This material was found to be paramagnetic and to display a relatively modest conductivity (urt = 0.001 Scm , semiconductor) [75]. Finally, the pentanuclear trigonal bipyramidal vanadium cluster [(MeCp)5V5(/r -S)6] was shown to undergo CT complex formation with TCNQ affording [(MeCp)5V5(/i -S)6] [(TCNQ)2] [76]. This material, which was structurally characterized, is an n-type semiconductor with a band gap of 0.25 eV. 

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