Porphyrin-bridged donor-acceptor molecules

Table 5. INDO/SCI-SOS Calculated /i Values at 1064nm for Porphyrin-Bridged Donor-Acceptor Molecules...

Theoretical calculations of the dependence of the probability of electron tunneling on mutual orientation of donor and acceptor fragments in bridge molecules were presented in Ref. [304], With the use of a cyclic polyene model to construct wave functions of porphyrin fragments, a number of analytical expressions were obtained for orientation dependence of probabilities of tunneling between these fragments. 

All the orbitals relevant for the charge separation are almost completely localized on either donor (D) or acceptor (A) for the systems under study. In the molecule PAQ, a porphyrin donor linked via an amide bridge to a quinon acceptor (see fig 1), the lowest unoccupied molecular orbital (LUMO) is localized on the acceptor whereas the next two higher (LUMO+l and LUMO-t-2) as well as the two highest occupied orbitals ( HOMO-1 and HOMO ) are situated on the donor (in fig 1 this can be seen for L-f 1 and L). 

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