Marcus theory porphyrins

Many other papers on long-range electron transfer between two reactive sites of modified proteins were published [270-288] after the above mentioned pioneering works. Most of them dealt with photoinduced electron tunneling from triplet states of closed shell Mg(II) and Zn(II) porphyrins to Fe(III) or Ru(III). In agreement with the prediction of Marcus theory the rate constants for the majority of these intraprotein electron transfer reactions were found to increase as the free energy of reaction decreased. However for one of the reactions disagreement with this theory was observed [285],... 

In 1983 Closs and Miller found the bell-shqied curve for charge shift reaction in a linked molecular system to verify the validity of Marcus theory [479,480,488,490,530,540,733-735]. A porphyrin-linked molecular system also exhibited the bell-shaped curve as described in Section IV.C. 

Among intensive studies on linked molecular systems, chromophoric assemblies, and supramolecular systems, most efforts have been focused on electron transfer processes in those systems [460,468,470-478,501]. As described in Section in.B, the inverted region predicted by the Marcus theory on electron transfer was found in the linked molecular system having donor and acceptor connected with the appropriate spacer group to verify the theory [479,480,488,490,530,540,733-735]. The inverted region was also observed in various linked molecular systems having porphyrins andmetalloporphyiins as shown in Fig. 53 (25,26) [481-484]. 

By using the series of Zn-porphyrins depicted in Figure 5.8(a) we could vary several molecular properties of importance for dye-semiconductor binding." From Marcus theory of electron transfer (and its modifications for... 

ABSTRACT. A theoretical study of the electron self-exchange in porphyrins and in cytochrome c, and of the free-energy dependence of poq)hyrin-cytochrome c systems ows that these reactions are not easily amenable to an explanation in the framework of the theory of Marcus. On the other hand the intersecting-state model can be used to calculate the self-exchange rates and ] ovide an useful rationalization of the free-energy relationsh obs ed in these systems. 

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