Fluorescence stabilization, porphyrins

Fluorescence stabilization, porphyrins la 100-101 Fluorophors la 57 Flupentixol lb 354 Fluphenazine la 104 lb 354-356 Fluspirilen lb 354 Fluvalinates lb 86 Foam bath, brominated la 64 Folic acid la 223,225 Folin-Ciocalteu s reagent lb 180 Folin s reagent lb 321 Formaldehyde la 299,351 -, vapor la 86 Formazan lb 65... 

According to the definition of multiporphyrin assembly given in the Introduction (Sect. 1), a dimeric hetero-assembly can be formed by A—A and B—B monomers only if both contain porphyrin subunits. An example is given by the dimer 24 (meso-aryl groups omitted) whose stability constant, iCsa = 3x10 mol 1, was determined in CH2CI2 by a fluorescence titration... 

X 10 mol L range, with a detection limit of 0.27 jM. The fluorescence energy transfer between ferrocene donor and porphyrin acceptor was also considered. Nanofibers with distinct luminescent property were fabricated by electrospinning porphyrinated polyimides. The new material demonstrated to be a very interesting sensory material for detection of trace amounts of TNT vapor (10 ppb) [249]. The presence of covalently bonded porphyrin fluorophores in the main chain diminish the aggregation-induced self-quenching of fluorescence and improves the physicochemical stability of the polyimide nanofibers. 

On increasing CD concentrations, more than 90% of the total fluorescence emission can be accounted by TPPS molecules embedded in the colloidal phase. Consequently, the porphyrin rotation is slowed down and they are actually stabilized onto the vesicles surface. Indeed, the anisotropy decays evidence a double-exponential behaviour, in which the predominant slow components exhibit rotational correlation times in the range of 20-25 ns and vq values of ca. 0.15. Such values of rotational diffusion times (>20ns) are too long for the simple CD vesicles (corresponding to radii > 1000 A). In a likely model TPPS molecules can be considered as embedded on the vesicles and the larger rotational correlation times correspond to the slow complete rotation of the CD/ porphyrin system and/or to local deformation of the colloidal wall [40]. 

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