Three comparative fluorescence emissions are shown to be observable from a common initial excited singlet state in a prototype aminosalicylate molecule: p-NR$\sb2$C$\sb6$H$\sb3$(OR$\sp\prime$)COOR$\sp{\prime\prime}$, PDASE (R = CH$\sb3$, R$\sp\prime$ = H and R$\sp{\prime\prime}$ = CH$\sb3$). All molecular structures are with the (OR$\sp\prime$) group ortho to the COOR$\sp{\prime\prime}$ group. The steady-state fluorescences are assigned as the normal fluorescence ${\rm S\sb1(\pi,\pi\sp\*) \to S\sb0}$, the twisted intramolecular charge-transfer or TICT-state fluorescence S$\sbsp{1}{\prime\prime}$(TICT) $\to$ S$\sb0$, and the intramolecular proton-transfer fluorescence S$\sbsp{1}{\prime}$(PT) $\to$ S$\sbsp{0}{\prime}$. Two excited state absorptions are also believed to be present for PDASE. The excited-state absorptions are assigned as the absorption from the first excited TICT singlet S$\sbsp{n}{\prime\prime}$(TICT) $\gets$ S$\sbsp{1}{\prime\prime}$(TICT), and the absorption from the first excited state of the proton-transfer tautomer S$\sbsp{n}{\prime}$(PT) $\gets$ S$\sbsp{1}{\prime}$(PT). / Several compounds were designed and synthesized to isolate the emission-type that was of interest. Among these were MABAE (R = H, R$\sp\prime$ = CH$\sb3$ and R$\sp{\prime\prime}$ = CH$\sb3$) which isolates for normal emission processes; PASE (R = H, R$\sp\prime$ = H and R$\sp{\prime\prime}$ = CH$\sb3$) which isolates for proton-transfer processes in the shifted or F$\sb2$ band; and, MDABAE (R = CH$\sb3$, R$\sp\prime$ = CH$\sb3$ and R$\sp{\prime\prime}$ = CH$\sb3$) which isolates for TICT processes in the F$\sb2$ band. Using steady-state absorption and emission, the relative shift in fluorescence wavelength maxima vs. the solvent polarity index E$\sb{\rm T}$, picosecond optical multichannel analyzer resolved transient absorption, and picosecond streak camera resolved fluorescence dynamics the assignments for the studied molecular systems were corroborated. / Source: Dissertation Abstracts International, Volume: 50-05, Section: B, page: 1959. / Major Professor: Michael Kasha. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78014 |
| Contributors | Gormin, David Austin., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 258 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.0014 seconds