A model for simulating the transient electronic absorption spectra of donor-acceptor dyads undergoing ultrafast intramolecular charge transfer in solution has been developed. It is based on the stochastic multichannel point-transition approach and includes the reorganization of high-frequency intramolecular modes (treated quantum mechanically) and of low frequency intramolecular and solvent mod...

Fluorescence resonance energy transfer and fluorescence polarization anisotropy are used to investigate single molecules of the enzyme staphylococcal nuclease. Intramolecular fluorescence resonance energy transfer and fluorescence polarization anisotropy measurements of fluorescently labeled staphylococcal nuclease molecules reveal distinct patterns of fluctuations that may be attributed to pro...

Some strategies toward the realization of molecular control of photo-induced charge-transfer processes at nanocrystalline semiconductor interfaces are discussed. Supramolecular compounds that efficiently absorb light, promote interfacial electron transfer, and feature additional functions such as intramolecular electron transfer when bound to semiconductor surfaces are of specific interest. Tun...

Excited-state proton transfer has been hypothesized as a mechanism for UV energy dissipation in eumelanin skin pigments. By using time-resolved fluorescence spectroscopy, we show that the previously proposed, but unresolved, excited-state intramolecular proton transfer (ESIPT) of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) occurs with a time constant of 300 fs in ...

The photophysics of indigo as well as of bispyrroleindigo, the basic chromophore of indigo, has been investigated with ab initio electronic-structure calculations. Vertical electronic excitation energies and excited-state potential-energy profiles have been calculated with the CASSCF, CASPT2 and CC2 methods. The calculations reveal that indigo and bispyrroleindigo undergo intramolecular single-...

Intramolecular photoinduced electron transfer from a hydrazine unit to an aromatic group is studied by resonance Raman spectroscopy and electronic absorption spectroscopy. Substituted hydrazine functional groups have played an important role in studies of electron-transfer reactions, photoinduced intramolecular electron transfer, and of mixed valence. A prototypical compound, 2-tert-butyl-3-(an...

The astonishingly efficient location and excision of damaged DNA bases by DNA repair glycosylases is an especially intriguing problem in biology. One example is the enzyme uracil DNA glycosylase (UNG), which captures and excises rare extrahelical uracil bases that have emerged from the DNA base stack by spontaneous base pair breathing motions. Here, we explore the efficiency and mechanism by wh...

The carotenoid peridinin is abundant in the biosphere, as it is the main pigment bound by the light-harvesting complexes of dinoflagellates, where it collects blue and green sunlight and transfers energy to chlorophyll a with high efficiency. Its molecular structure is particularly complex, giving rise to an intricate excited state manifold, which includes a state with charge-transfer character...

DNA chips are widely used for genomic analysis. Currently, high-density DNA chips can be synthesized with up to several hundred thousand different spots on an area of 1 cm. In principle, the complete human genome can be probed with such a chip. The required high spot densities can be achieved by photolithographic in situ DNA-chip synthesis. In this method, the oligonucleotides are synthesized s...

Molecules capable of performing highly efficient energy transfer and ultrafast photoinduced electron transfer in well-defined multichromophoric structures are indispensable to the development of artificial photofunctional systems. Herein, we report on the synthesis, characterization, and photophysical properties of a rationally designed multichromophoric tetracationic cyclophane, DAPPBox4+, con...