Sandwich complexes electrochemistry

Examples of EE processes abound in transition metal electrochemistry. One that conveniently shows the effect of AE° on wave shapes is that involving the two-step reduction of the sandwich complexes, where M = Rh or Ir ... 

Figure 1 Lutetium sandwich complexes 2. Electrochemistry and spectroelectrochemistry of LuPc2...

Electrochemistry. The redox processes for porphyrazines 21, 25, 28, 29, the heteroleptic Zr (pz/porphyrin) 30 and 31 have been measured by cyclic voltammetry and the formal potentials are given in Table VII. The potentials are compared to the available data for the analogous porphyrin and pc complexes. In general, the electrochemical behavior of the pz sandwiches more closely mirror that observed for the phthalocyanines than the porphyrins. In particular, all of the porphyrazines have at least one ring-based oxidation, attributable to the formation of the bis Jt-radical cation for Lu(III) sandwiches and the formation of the 7T-radical cation for the Zr(IV) and Ce(IV) sandwiches. Additionally, all of the porphyrazines exhibit at least one ring-based reduction. 

Porphyrins have been found to bind the tetravalent ions of Th and U in the form of the bisporphyrin complexes, An(P)2 (An = Th, U P = octaethylporphyrin, tetra-j -tolylporphyrin). These sandwich-type complexes are useM for studying the electronic structure of porphyrins. For example, Th is electrochemically inactive, which allows the porphyrin-based electrochemistry to be studied exclusively for its role in photosynthesis. 

Although the redox behavior of double- and triple-decker porphyrinato complexes has been well documented, the electrochemical properties of half-sandwich analogs remain little studied. The first systematic study of the electrochemistry of this class of tetrapyrrole derivatives was reported by Kadish et al. (1991). The complex Eu(TPP)(facam) was examined, and was found to have higher stability in the oxidized and reduced forms than the corresponding acac and tmhd analogs. The compound can be prepared by treating Eu(TPP)(acac) with 3-(trifluoroacetyl)camphor (Hfacam) and sodium hydroxide in an EtOH/water mixture. As shown in fig. 12, Ae cyclic voltammograms of Eu(TPP)(facam)... 

The electrochemistry of many sandwich and carbonyl arene complexes was studied. 

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