Journal of Fluorescence

, Volume 26, Issue 2, pp 679–688

Light-Enhanced Fluorescence of Multi-Level Cavitands Possessing Pyridazine Upper rim

  • Tibor Zoltan Janosi
  • Geza Makkai
  • Timea Kegl
  • Peter Matyus
  • Laszlo Kollar
  • Janos Erostyak
ORIGINAL ARTICLE

DOI: 10.1007/s10895-015-1754-3

Cite this article as:
Janosi, T.Z., Makkai, G., Kegl, T. et al. J Fluoresc (2016) 26: 679. doi:10.1007/s10895-015-1754-3

Abstract

Completely different fluorescence behaviour of cavitands based on a same calix[4]resorcinarene compound was observed. While the fluorescence intensity of the parent compound, tetramethyl-cavitand (1) slowly faded as a result of UV-light exposure, the emission of the three-level cavitand with pyridazine moieties at the upper rim (5a) was enhanced by the excitation in the UV-region. The structure of fluorescence emission (characterized by excitation-emission matrices) and the absorption of 5a remained unaltered. The analysis of fluorescence decay curves reveals the presence of two separated components assigned to two individual emitting species. The measured significant increase of the average lifetime and quantum yield is the consequence of the UV-light induced transition between the different states of 5a. These observations can be explained by the structural difference between 5a and 1. As a counterpart of the naked cavitand (1) with methyl substituents at the upper rim only, 5a has three additional moieties benzene, triazole and pyridazine levels. Computational studies proved the existence of two conformational isomers of 5a. Upon ultraviolet light excitation a “dark” to “light” conformational transition occurs between the two isomers. This hypothesis was confirmed by anisotropy decay measurements.

Keywords

Triazole pyridazine cavitand Fluorescence enhancement Conformational isomer Internal fluorescence quenching Photochromism Photoswitchable material 

Supplementary material

10895_2015_1754_MOESM1_ESM.doc (33.6 mb)
ESM 1(DOC 34365 kb)

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Tibor Zoltan Janosi
    • 1
    • 2
  • Geza Makkai
    • 1
    • 2
  • Timea Kegl
    • 3
    • 4
  • Peter Matyus
    • 5
  • Laszlo Kollar
    • 3
    • 4
  • Janos Erostyak
    • 1
    • 2
  1. 1.Institute of PhysicsUniversity of PecsPecsHungary
  2. 2.Szentagothai Research Centre, Spectroscopy Research GroupUniversity of PecsPecsHungary
  3. 3.Department of Inorganic ChemistryUniversity of PecsPecsHungary
  4. 4.MTA-PTE Research Group for Selective Chemical SynthesesPecsHungary
  5. 5.Department of Organic ChemistrySemmelweis UniversityBudapestHungary

Personalised recommendations