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The fabrication and photophysical characterization of a multichromophore array, [(Z3PN).sub.4]PDI, comprising of four zinc 5-phenyl-10,15,20-tri(n-pentyl)porphyrins(Z3PN) linked to the 1,7,N,N'-positions of perylene-3,4:9,10-bis(dicarboximide)(PDI) is described. The comparison of the two model compounds, N,N'-[(Z3PN).sub.2]PDI and 1,7-[(Z3PN).sub.2]PDI with the dynamics of energy and charge transport within the system is conducted.

Appending a stable radical to the bridge molecule in a donor--bridge--acceptor system (D-B-A) is potentially an important way to control charge- and spin-transfer dynamics through D-B-A. Using both time-resolved optical and EPR spectroscopy, it is shown that nitronyl nitroxide (NN*) influences the spin dynamics of the photogenerated triradical states (super 2,4)(MeOAn-6ANI-Ph(NN*)-(super 3*)NI), in which NN* is strongly spin-polarized.

Femtosecond transient absorption spectroscopy and time-resolved EPR spectroscopy (TREPR) are used to investigate the photoinduced charge transfer and spin dynamics of the perylenediimide chromophore in to DNA hairpins as a base-pair surrogate. The chromophore effectively injects holes into adjacent nucleobases depending on the polaron generation.

The synthesis and photophysical properties of butadiyne-linked chlorophyll and porphyrin dimers in toluene solution and in several self-assembled prismatic structures are described. The self-assembly of discrete macrocyclic prisms provides a new method for controlling singlet exciton flow in antenna systems for artificial photosynthesis and solar cell applications.

A zinc chlorophyll (ZC) derivative is prepared that self-assembles into a cyclic tetramer and displays intramolecular energy transfer rates comparable to those for covalent ring structures. It is shown that larger transition dipole moment for the lowest energy electronic transition of the ZCs compared to that of the porphyrins has increased the rate of Forster energy transfer between the chlorophylls.

Suzuki cross-coupling reactions afforded 20-phenyl-substituted Chlorophyll a derivative in good yields and significant quantities from readily available Chlorophyll a. The versatility of this new functionality has resulted in the synthesis and characterization of a series of ZCPh-arylene bis(dicarboximide) donor-acceptor dyads.

Small-angle X-ray scattering (SAXS) studies on m-phenylene ethynylene oligomer (mPE) in acetonitrile is presented which provides the first time direct structural data on a mPE foldamer in solution. It is seen that X-ray scattering can be employed as a general methodology for direct structural studies of foldamers in solution.

Photoinduced charge separation is observed in perlene-3,4:9,10-bis(dicarboximide) (PDI) molecules, using electron-nuclear double resonance ( ENDOR) spectroscopy. The ENDOR data clearly show that rapid electron hopping occurs both in covalent and self-assembled pi-stacked PDI molecules and the combination of electronic absorption and ENDOR data establishes limits on the time scale for electron transfer.

The article discusses electron hopping in π-stacked covalent and self-assembled perylene dimides observed by electron-nuclear double resonance (ENDOR) spectroscopy. The delocalization or rapid hopping of charge among neighboring molecules is a requirement for organic electronics including photovoltaics. Electron paramagnetic resonance and ENDOR spectroscopy are used to reveal charge sharing in dimers. The combination of electronic absorption and ENDOR spectroscopy establishes limits on the time scale for electron transfer between π- stacked chromophores. The 50% reduction of hfcc's for the dimeric systems relative to the monomer models reveals that the rate of electron hopping between the PDIs in both 3.- and (4).-2 is many times faster than the ENDOR time scale (1O7 Hz).