Bessel and Rolison

Bessel and Rolison reported the electrochemical behavior of [Co(SALEN)]2"1" and Fe(bpy)3]2+ in zeolite Y.[1571 They prepared an electrode using the complex-zeolite composite and carbon powder, and tested the electrochemical behaviors of the electrode and the composite dispersed in a solution. It was found that the electrochemical behaviors of these two materials differ to a great extent. After several cycles, the former loses all the electrochemical signals, whereas the latter continuously shows the signals. They believed that the electrochemical signals arise from the complex attached onto the zeolite external surface (defects or external supercages), whereas the complex inside the zeolite channel does not participate in electron transfer of the electrochemical process. In fact, there has been dispute on whether the electrochemical signals arise from electron transfer in zeolite channels or from those complexes on the zeolite external surface. Both views can find experimental support.1158 1591... 

Nanoparticle electrogeneration and attachment to porous materials (Bessel and Rolison, 1997a)... 

Coelectrodeposition with conducting polymers from a material-monomer slurry submitted to electropolymerization conditions. Thus, Rolison (1990) prepared uniform particle-polymer coatings from a drop of zeolite suspension in a pyrrole solution in Et4NC104/MeCN (see also Bessel and Rolison, 1997a). 

To elucidate reaction pathways, several experimental features have to be considered (Bessel and Rolison, 1997a Domenech et al., 2002a, 2003a, 2004e) ... 

The encapsulation of catalytically active species into porous solids is one of the possible strategies of particular interest. Thus, Bessel and Rolison (1997b,c) compared the electrocatalytic effect of zeolite Y-encapsulated Co(salen) (salen = N,N -bis(salicylidene)ethylenediamine) on the reaction between benzyl chloride and carbon dioxide in tetrahydrofuran/hexamethylphosphoramide, with that exerted by the same complex in solution. Using a large surface area reticulated vitreous carbon electrode immersed into suspensions of Co(salen) NaY in solutions of the reagents, the effective electrocatalytic turnover is ca. 3000 times that of homogeneous Co(salen) under comparable conditions. Remarkably, coulometric experiments indicated that only... 

C.A. Bessel and D.R. Rolison, Topological Redox Isomers Surface Chemistry of Zeolite-encapsulated Co(salen) and [Fe(bpy)3]2+ Complexes. J. Phys. Chem. B, 1997, 101, 1148-1157. 

Bessel, C.A., and Rolison, D.R. 1997a. Topological redox isomers Surface chemistry of zeolite-encapsulated Cofsalcn) and fc(bpv),P complexes. Journal of Physical Chemistry B 101, 1148-1157. 

D.R. Rolison, C.A. Bessel, M.D. Baker, C. Seneratne, and J. Zhang, Reply to the Comment on Zeolite-modified Electrodes Intra- versus Extrazeolite Electron Transfer . J. Phys. Chem., 1996, 100, 8610-8611. 

This scheme can be extended to nonconducting or semiconducting nanoporous solids incorporating redox-active centers via chemical doping prompted by sol-gel methodologies (Domenech and Alarcon, 2002b, 2003 Domenech et al. 2004b-d). Eventually, the materials can be electrochemically modified (Rolison and Bessel, 2000). 

Rolison, D.R., and Bessel, C.A. 2000. Electrocatalysis and charge-transfer reactions at redox-modified zeolites. Accounts of Chemical Research 33, 737-744. 

Rolison, D.R., Bessel, C.A., Baker, M.D., Senaratne, C., and Zhang, J. 1996. Reply to the comment on Zeolite-modified electrodes Intra- versus extrazeolite electron transfer. Journal of Physical Chemistry 100, 8610-8611. 

Bessel, C.A. and D.R. Rolison (1997). Electrocatalytic reactivity of zeolite-encapsulated Co(salen) with benzyl chloride. J. Am. Chem. Soc. 119(51), 12673-12674. 

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