+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Intramolecular charge transfer in aminobenzonitriles and tetrafluoro counterparts: fluorescence explained by competition between low lying excited states and radiationless deactivation. Part II: influence of substitution on luminescence patterns

, : Intramolecular charge transfer in aminobenzonitriles and tetrafluoro counterparts: fluorescence explained by competition between low lying excited states and radiationless deactivation. Part II: influence of substitution on luminescence patterns. Physical Chemistry Chemical Physics 18(9): 6875-6884

In this paper, we study the mechanisms of charge transfer, luminescence and radiationless decay of three derivatives of 4-aminobenzonitrile (ABN): dimethyl-ABN (DMABN) and the tetrafluorinated derivatives, ABN-4F and DMABN-4F. Our CASSCF/CASPT2 computations explain the different luminescence patterns observed in these three compounds and in comparison with the parent system, ABN, in spite of their similar architecture. We have found that the modifications made by the different substitutions in ABN tune the relative energies of the locally excited (LE) and charge transfer (CT) excited states due to electronic and structural factors. In all cases, the only potentially emitting species of CT character is the twisted-ICT. The increasing stabilization of this later species in the series formed by ABN-4F, DMABN and DMABN-4F explains the increasing intensity of the anomalous emission band in these compounds. Nevertheless, other factors like probability of emission vs. nonradiative decay must have also been taken into account. In fact fluoro-substitution increases the accessibility to conical intersections of the excited states with the ground state, opening an internal conversion channel that decreases the fluorescence quantum yield in the fluorinated derivatives. Our results also show that the involvement of the π-σ* state in the CT process is only possible in ABN-4F, but even in this case it is not probable.


PMID: 26878811

DOI: 10.1039/c5cp04693a

Other references

Libanoff A.J.; Rodbard S., 1968: Atrio ventricular pressure half time measure of mitral valve orifice area human inst cardiac catheterization. Circulation 38(1): 144-150

Klobusicky, M.; Buchwald, J., 1970: Contribution to the method of sampling the skin of animals for mycological examination. A method for collecting skin scales and hairs by applying an adhesive plaster ' Spofaplast' to the foci of trichophytosis or to the intact skin is described. The plaster is then either brought in contact with the surface of culture mediu...

Stoinov, S.; Mendizova, A.; Nacov, V.; Penchev, P.; Savov, G.; Tsolova, N.; Gerova, V.; Kadiyan, H., 2000: Evaluation of bowel motility in patients with chronic alcoholism by means of lactulose hydrogen breath test. Dokladi na B"lgarskata Akademiya na Naukite 53(10): 119-121

Battenfield, F.L.; Kent, A., 2007: The culture of communication among intercollegiate sport information professionals. This study was conducted to 'crack the code' of the culture of communication in the Division I-A sports information office. An ethnographic study was utilized to discover the verbal, non-verbal and technological communication methods of...

Seabra, L.D.F.rreirinha, M.P.; Freitas, M.C.P.G.D., 1956: Notes on forestry in Goa.. Forests cover ca. 159, 924 ha. of the total surface area of 3983 sq. km. Notes are presented on the aims of the admini-stration with regard to the forests and on some of the more important tree species and their uses.

Inokuti, M.; Seltzer, S.M., 2002: Physics as an element of radiation research. Since its inception in 1954, Radiation Research has published an estimated total of about 8700 scientific articles up to August 2001, about 520, or roughly 6%, of which are primarily related to physics. This average of about 11 articles per year i...

Pastor, M.Carmen.; Moltó, J.; Vila, J.; Lang, P.J., 2004: Startle reflex modulation, affective ratings and autonomic reactivity in incarcerated Spanish psychopaths. Startle probe modulation during affective picture viewing was assessed in a Spanish prison population. As for North American inmates, psychopaths failed to display normal blink potentiation during unpleasant slides even though their evaluative jud...

Yasuda, S.; Yogosawa, S.; Izutani, Y.; Nakamura, Y.; Watanabe, H.; Sakai, T., 2010: Cucurbitacin B induces G2 arrest and apoptosis via a reactive oxygen species-dependent mechanism in human colon adenocarcinoma SW480 cells. Cucurbitacin B (cucB) is a triterpenoid constituent of Cucurbitaceae vegetables and a promising phytochemical for cancer prevention. However, the mechanism of anti-tumor activity of cucB remains unknown, especially in colon cancers. Here, we demon...

Lewis, B.S.; Shefer, A.; Flugelman, M.Y.; Merdler, A.; Halon, D.A.; Hardoff, R., 1989: Effect of the second-generation calcium channel blocking drug nisoldipine on diastolic left ventricular dysfunction in heart failure. The effect of intravenous nisoldipine (0.12 microgram/kg/min) on diastolic left ventricular (LV) dysfunction was studied from simultaneous hemodynamic and radionuclide measurements in 12 patients with New York Heart Association class II to IV card...

McGuire, T.; Moody, J.; Hanson, M., 1997: Managers' attitudes towards mechanical aids. This article reports a study of the attitudes of NHS management and financial personnel to issues of moving and handling, in particular the use of mechanical aids. The study highlights some confusions about the responsibilities and roles of differ...