The computational and experimental investigations of photophysical and spectroscopic properties of BF2 dipyrromethene complexes

R. R. Valiev, A. N. Sinelnikov, Y. V. Aksenova, R. T. Kuznetsova, M. B. Berezin, A. S. Semeikin, V. N. Cherepanov

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The electronic excited states of BF2 dipyrromethene (2BrDPM, DPMI, DPMII, PM567 and 4PhDPM) complexes were investigated using the extended multi-configuration quasi-degenerate at the second order of perturbation theory (XMCQDPT2) and the second-order approximate coupled-cluster (CC2) methods. The excitation energies calculated by CC2 are significantly overestimated by 0.42-0.59 eV because of the substantial contributions of double excitation levels to excited states (>10%). However, the calculated XMCQDPT2 excitation energies agree well with experimental ones within the accuracy 0.11-0.20 eV. The very low lasing efficiency (7.8-8.4%) of 4PhDPM compound was explained by the T1 → T4 and T1 → T5 reabsorptions at XMCQDPT2 level of theory. The molecular photonics of pyrromethenes are studied using a combination of the first-principle and semi-empirical calculations. The main mechanism for the deactivation of the energy of the first singlet excited electronic state is the radiative electronic transition for DPMI, DPMII, PM567 and 4PhDPM compounds. Also, the main mechanism for the quenching of fluorescence in considered complexes (except DPMII compound) is the internal conversion. The processes of the internal conversion and intersystem crossing compete with each other in DPMII compound. The measured and calculated fluorescence quantum yields agree well for all considered molecules.

Original languageEnglish
Pages (from-to)323-329
Number of pages7
JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Volume117
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • Internal conversion
  • Intersystem crossing
  • Photophysics
  • Quantum yields

ASJC Scopus subject areas

  • Analytical Chemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Spectroscopy

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