Symmetry Effects in Photoinduced Electron Transfer in Chlorin-Quinone Dyads: Adiabatic Suppression in the Marcus Inverted Region.

In donor-acceptor dyads undergoing photoinduced electron transfer (PET), a direction or pathway for electron movement is usually dictated by the redox properties and the separation distance between the donor and acceptor subunits, while the effect of symmetry is less recognized. We have designed and synthesized two isomeric donor-acceptor assemblies in which electronic coupling between donor and acceptor is altered by the orbital symmetry control with the reorganization energy and charge transfer exothermicity being kept unchanged. Analysis of the optical absorption and luminescence spectra, supported by the DFT and TD-DFT calculations, showed that PET in these assemblies corresponds to the Marcus inverted region (MIR) and has larger rate for isomer with weaker electronic coupling.

Photodynamic performance of amphiphilic chlorin e6 derivatives with appropriate properties: A comparison between different-type liposomes as delivery systems.

Background: Many aspects are currently being investigated, with the aim of improving the application of PDT in the clinic by rendering it more effective. One of the current trends focuses on the use of nanocarriers. The aim of this study is to describe novel photosensitizers among polyol amide chlorin e6 derivatives for photodynamic therapy (PDT) using liposomes.

Iron Chelators and Exogenic Photosensitizers. Synergy through Oxidative Stress Gene Expression.

In non-invasive anticancer photodynamic therapy (PDT), a nontoxic photosensitizer (PS), which is activated by visible light, is used as a magic bullet that selectively destroys cancer cells. Recently, we described the combined therapy of 5-aminolevulinic acid (ALA-PDT) with thiosemicarbazone (TSC), i.e.

Radiolabelling and preliminary evaluation of 68Ga-tetrapyrrole derivatives as potential tracers for PET.

Tetrapyrroles are multisided natural products which are of relevance in clinical medicine. Owing to their specific accumulation in tumour tissue, porphyrins, metalloporphyrins and chlorins have been used as in photodynamic therapy and optical imaging. Moreover, their specific uptake into inflammatory atheromatous plaques via LDL endocytosis has been reported.

Photoprocesses of chlorin e6 glucose derivatives.

The ground and excited state processes of chlorin e6, the monomethyl ester C1, the glucose derivative C2 and the 3-heptylchlorin-glucose C3, were studied in solvents of lower and higher polarity. The excited singlet and lowest triplet states of C1-C3 were characterized by spectroscopic methods for several conditions. The quantum yields of formation of singlet molecular oxygen and the other triplet properties of the three chlorins and chlorin e6 are similar, whereas the fluorescence quantum yield decreases on going from C1 to C3.

Spectroscopic and biological studies of a novel synthetic chlorin derivative with prospects for use in PDT.

Photosensitizers with desirable combinations of chemical, photophysical and biological properties are essential for improving the efficacy of photodynamic therapy (PDT) against various cancers. Chlorins seem to be promising candidates for photodynamic therapy (PDT) owing to their photophysical properties. This paper reports spectroscopic and biological properties of a novel synthetic chlorin derivative.

Synthesis of a peptide-linked chlorin dyad as a model compound for the photosynthetic reaction centre.

The enantiomerically pure chlorins 19 and 21 were synthesised from tripyrrolic nickel complex rac-17 and pyrrole building blocks 12 and 16. The pyrroles are annelated with norbornane moieties which contain the chiral information as well as two different functionalities. The functional groups, namely a carboxylic acid ester and a carbonitrile group, of chlorin 21 finally allowed the formation of an amino acid functionality at the periphery of the macrotetracycle.

Unusual role of oxygen in electron-transfer processes.

Molecular oxygen's unique involvement in electron-transfer processes is demonstrated on a series of dyads between porphyrin derivatives and fullerene C60. It has been shown for the first time that oxygen can serve as an inhibitor of back electron transfer by enhancing intersystem crossing of a singlet radical ion pair into its triplet state. The effect is observed only when energy of the charge-separated state is lower than that of the locally excited triplet states.