Electrochemical ring-closing reaction

Scheme 15.5 Illustration of the formation of the trans- and a.v-ring-closed isomers of 34 by electrochemical ring-closing reaction.

Photochromic dithenylmaleimide 32 contains two ferrocene units.41 Electrochemical absorption spectral studies indicate that oxidation of ferrocenyl units can induce ring-opening reaction for the ring-closed isomer of 32. 

In the dc case, the current has to flow to the electrochemically active sites close to the 3PB and a considerable current constriction results (Fig. 22b). Hence, the dc resistance consists of the resistance due to the electrochemical reaction and the bulk resistance, which includes the current constriction in the vicinity of the active ring. At higher frequencies, the inner part of the microelectrode becomes dielectrically permeable and the current flows to the entire microelectrode area (Fig. 22c). In other words, the current lines in the bulk, and thus the bulk resistance, are frequency-... 

Earlier we have studied the reactions of fullerene Cgo with the isocyanurato-, phosphoryl-, pyrimidino-, nitropyrimidino-, quinoxalin-, benzopyrazine substituted azides [18-24]. As a result, both 6,6-, 5,6-closed and 5,6-open organofullerens were synthesized, and the series of them were reduced electrochemically easier than the pristine fullerene C6o- Now the reactions of fullerene C6o with isocyanurato- and nitropyrimidine substituted azides were used for the search of the answer to delivered question. For solving the problem the substituents in positions 1 and 3 of the isocyanurate ring and the number of methylene units between ring and azide group in isocyanurate containing azides were varied. 

The response recorded in many electrochemical experiments is extensively changed by the chemical reactivity of the product of electron transfer. Indeed, the study of chemical reactions of intermediates either adsorbed on the surface or free in the solution close to the electrode surface has become a major application of several techniques, e.g. cyclic voltammetry, rotating ring disc electrodes, spectroelectrochemistry, and double potential step. 

---