Spectral and photochemical properties of bifunctional compounds and their complexes

Abstract

Quantum yields of the step-by-step photocyclization of diphenylamine (DPA) derivatives Ph2N--(CH2),~--NPh 2. n = 3--6, 9. to the corresponding ct.0)-di(carbazolyl)alkanes were measured. At n > 3, the presence of the second DPA group had no effect on the cyclization of the first DPA group: however, cyclization of the second DPA group was retarded after cycIization of the first DPA group. 3he effect was explained by quenching of the excited DPA group by the carbazole group newly formed in the semi-cyclic compound. For disubstituted propane (n = 3), the mutual influence of the two groups at both stages of the reaction was found.

UV spectral features of poly(propylene imine) dendrimers

“…The Lorentziantype components of 20 and 14 nm width were observed at 275 and 284 nm, respectively. It should be noted that double band structure was also determined in the absorption spectra of a series of diamino-alkanes [20]. The line shape of components in the double band was similar for all dendrimer generations.…”

Energy transfer, fluorescence and photoisomerization of styrylquinoline–naphthol dyads with dioxypolymethylene bridges

“…This can be compared with "Hirayama rule" that diaryl alkane (covalently linked dyad) with three-methylene carbon chain has the highest ability to form intramolecular excimer [1,38]. There are other examples when three-methylene bridge between two fragments creates the most favorable conditions for the interfragment interaction in bichromophoric dyads [39,40]. It should be noted that optimal bridge length for the strongest interaction between chromophores depends on the chromophore nature and may differ from three-methylene chain [41].The ET efficiency and the Forster radius are connected by Eq.…”