Multichromophores

The possibility of their bearing multichromophores (arranged either symmetrically or asymmetrically about the core)... 

I., Beljonne, D., Champagne, B., Mullen, K., Sauer, M., Hofkens, J. andDe Schryver, F. C. (2004) Multichromophoric dendrimers as single-photon sources a single-molecule study. J. Phys. Chem. B., 108, 16686-16696. 

Terenziani F, D Avino G, Painelli A (2007) Multichromophores for nonlinear optics designing the material properties by electrostatic interactions. Chemphyschem 8 2433-2444... 

DHT may occur over different tryptophan forms in proteins as they quite often have inhomogeneously broadened electronic spectra [31]. A very interesting case of DHT is described between two indole rings in bichromophoric solutes tryptophan dipeptide [32]. Such directed transport allows to correctly interpret spectral properties of dipeptide and other multichromophoric solutes. The theory of inductive-RET in solutions with inhomogeneous spectral broadening is given in Ref. [33]. In more detail, DHT mechanism will be explained in Sect. 2.2 (vide infra). 

M. J. Shephard, M. N. Paddon-Row, Large Predicted Changes in Geometry Accompanying Charge Separation in Various Rigid Multichromophoric Systems in the Gas Phase An ab Initio MO Study , J. Phys. Chem. A 1999,103, 3347-3350. 

Figure 14. Confocal fluorescence images of single molecules of (a) the model compound 69 and (c) the multichromophoric dendri-mer 70 in a polyvinylbutyral (PVB) film. The fluorescence intensity transients (fluorescence intensity versus time) exhibit typical on-off behavior for 69 (b) and jumps between different emissive levels for 70 (d). Pictures taken from ref. [48],...

Bodenant B, Fages F, Delville MH (1998) Metal-induced self-assembly of a pyrene-tethered hydroxamate ligand for the generation of multichromophoric supramolecular systems. The pyrene excimer as switch for iron(III)-driven intramolecular fluorescence quenching. J Am Chem Soc 120 7511-7519... 

Serin JM, Brousmiche DW, Frechet JMJ (2002) Cascade energy transfer in a conformation-ally mobile multichromophoric dendrimer. Chem Commun 21 2605-2607... 

Chen CH, Liu KY, Sudhakar S, Lim TS, Fann W, Hsu CP, Luh TY (2005) Efficient light harvesting and energy transfer in organic-inorganic hybrid multichromophoric materials. J Phys Chem B 109 17887-91... 

Bazan GC (2007) Novel organic materials through control of multichromophore interactions. J Org Chem 72 8615-8635... 

Berberan-Santos M. N., Choppinet P., Fedorov A., Jullien L., Valeur B. (1999) Multichromophoric Cydodextrins. 6. Investigation of Exdtation Energy Hopping by Monte-Carlo Simulations and Time-Resolved Fluorescence Anisotropy, J. Am. Chem. Soc. 121, 2526-2533. 

Multichromophoric systems consisting of two benzoate chromophores and another chro-mophore are subject to additivity relation in the amplitudes of exciton Cotton effects145, similar to that found for polybenzoate systems (Section 4.4.2.4.). 

A simple method has been developed to construct a variety of molecular architectures containing free base-magnesium or magnesium-metalloporphyrin systems consisting of two to nine porphyrin units. Compound 25 is a typical example for such a compound that are important for studying the electronic communication in multichromophoric... 

Our objective is to understand how the noncovalent interactions responsible for nucleic acid secondary structure (i.e. base stacking and base pairing) affect the photophysics of these multichromophoric systems. Here we describe initial experimental results that demonstrate dramatic differences in excited-state dynamics of nucleic acid polymers compared to their constituent monomers. Although ultrafast internal conversion is the dominant relaxation pathway for single bases, electronic energy relaxation in single-stranded polynucleotides... 

Another aspect of supramolecular photochemistry concerns the use of covalently linked bichromophoric and multichromophoric molecules. In the example of Figure 8.19 a two-step sequential, photoinduced electron transfer is observed in the trichromophoric species D-D-A. Local excitation of the cyanonaphthalene acceptor results in charge separation first to the amine and then to the methoxyaniline donor in times of a few tens of ns... 

The dye-loaded dendrimer 110 can be detected by means of single-molecule fluorescence.48,57,281,282 This multichromophoric system was embedded into a thin polymeric film at very low concentrations so that individual dendrimer molecules could be studied by far-field fluorescence microscopy at room temperature. Temporal fluorescence intensity fluctuations, fluorescence spectra, and decay times were measured separately or simultaneously. Collective on/off jumps of the fluorescence intensity as well as different emissive levels were observed for single dendrimer molecules with eight perylenemonoimide chromo-... 

---