Effect of the C(3)-Substituent in Verdazyl Radicals on their Profluorescent Behavior

Authors

  • Steffen Eusterwiemann Institute of Organic Chemistry, Department of Chemistry and Pharmacy, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
  • Hellmut Eckert Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany; Instituto da Física em Sao Carlos, Universidade de Sao Paulo, Avenida Trabalhador Saocarlense 400, Sao Carlos, SP 13560, Brazil. eckerth@uni-muenster.de
  • Cristian A. Strassert Center for Nanotechnology, Institute of Physics, Westfälische Wilhelms-Universität Münster, Heisen-bergstrasse 11, 48149 Münster, Germany. ca.s@uni-muenster.de
  • Nikos L. Doltsinis Institut für Festkörpertheorie and Center for Multi- scale Theory & Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany. nikos.doltsinis@uni-muenster.de
  • Constantin G. Daniliuc Institute of Organic Chemistry, Department of Chemistry and Pharmacy, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
  • Carsten C Doerenkamp Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
  • Sina Klabunde Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
  • Linda Stegemann Center for Nanotechnology, Institute of Physics, Westfälische Wilhelms-Universität Münster, Heisen-bergstrasse 11, 48149 Münster, Germany
  • David Matuschek Institute of Organic Chemistry, Department of Chemistry and Pharmacy, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
  • Armido Studer Institute of Organic Chemistry, Department of Chemistry and Pharmacy, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany. studer@uni-muenster.de

DOI:

https://doi.org/10.2533/chimia.2016.172

Keywords:

Epr, Profluorescence, Spin traps, Tddft, Verdazyl radicals

Abstract

Methods for the detection of reactive intermediates such as transient radicals are important in organic chemistry, polymer chemistry, biology or medicine. Along these lines we recently reported that 1,5-diphenyl-6-oxo verdazyl radicals can be used as fluorescent spin sensors. In situ generated C-centered radicals are efficiently trapped by the verdazyls, which in turn undergo transformation from a paramagnetic non-fluorescent state to a diamagnetic fluorescent state. Whereas the N-phenyl substituent in the spin probes is of high importance for obtaining profluorescent behavior, the effect of the C(3)-substituent has not been investigated to date. We herein present the synthesis and characterization of various 1,5-diphenyl-6-oxo-verdazyl radicals bearing differently hybridized C-substituents at the C(3) position. Steady-state and time-resolved fluorescence spectroscopy in solution and in the solid state along with time-dependent density functional theory (TDDFT) calculations reveal that a C(3)-aryl substituent is crucial for obtaining fluorescence after spin trapping. In addition, it is shown that the emission wavelength of the C(3)-aryl substituted verdazyl derivatives can be tuned by selective destabilization of the HOMO and the LUMO.

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Published

2016-03-30

Issue

Section

Scientific Articles

How to Cite

[1]
S. Eusterwiemann, H. Eckert, C. A. Strassert, N. L. Doltsinis, C. G. Daniliuc, C. C. Doerenkamp, S. Klabunde, L. Stegemann, D. Matuschek, A. Studer, Chimia 2016, 70, 172, DOI: 10.2533/chimia.2016.172.