Dipole-dipole transfer between acetone solvates of chlorophyll a and chlorophyll a dihydrate dimers in water/acetone mixtures. A model for P680 sensitized excitation

Aggregation processes and photophysical properties of chlorophyll a in aqueous solutions modulated by the presence of cyclodextrins

“…In both cases, the increasing of the cyclodextrine concentration in solution produces a gradual increase of the fluorescence signal. As well documented in the literature, 30 the chlorophyll aggregates do not show any detectable fluorescence because of a dipoledipole energy transfer between the porphyrinic rings. 22 The presence of fluorescence signals seems to indicate that the absorption peak at 670 nm can be ascribed to the presence of the pigment momeric form, as further confirmed by the fluorescence quantum yield of 72% presented by of a 10 À5 M solution of Chl in DIMEB (0.17 M), compared to that obtained for the monomer at the same Chl concentration in ether.…”

Cyclodextrin/chlorophyll a complexes as supramolecular photosensitizers

“…3). It is well known that chlorophyll aggregates do not show any detectable fluorescence emission because of an internal energy transfer between the porphyrin rings; moreover Chl a aggregates show a conservative peak in the red region of circular dichroism spectra [18]. In Fig.…”

Electrochemical characterization of species involved in photosynthesis: from proteins to model systems

“…The evident relevance of the pigment ability to mutate its physico-chemical properties upon aggregation has induced several laboratories to investigate the conditions at which long-wavelength absorbing forms of chlorophyll can be formed in vitro, in polar and nonpolar solvents and in a series of membrane mimetic systems [14][15][16]. Due to the complexity of the system under investigation and the number of parameters that can influence the Chl a aggregation processes, any study on the equilibrating species in solution may be rather difficult, and needs a large number of techniques to be carried out.…”