Herein, we present a combined spectroscopic and computational study on 5,5′-linked and 10,10′-linked corrole dimers, 5CD and 10CD, respectively, to reveal their strikingly different excited-state dynamics. The excited-state dynamics of 10CD indicate relatively small electronic interactions between the two corrole units, which is similar to the case of the meso-meso directly linked Zn(ii) porphyrin dimer. On the other hand, 5CD exhibits characteristic excitation-wavelength-dependent dual fluorescence. Transient absorption spectra of 10CD on the picosecond timescale showed torsional relaxation with a time constant of 25 ps, whereas the torsional relaxation of 5CD was faster, exhibiting a time constant of 10 ps. Quantum calculations have indicated that the eccentric dual fluorescence and the faster torsional relaxation process of 5CD are consequences of a large π-orbital coefficient at the connecting 5-position, which enhances the conjugative stabilization in the excited-state. In contrast, a small π-orbital coefficient at the 10-position and a larger torsional barrier of 10CD cause monomer-like characters in the excited-state.
Bibliographical noteFunding Information:
This work at Yonsei University was supported by the Global Research Laboratory Program (2013K1A1A2A02050183) funded by the Ministry of Science, ICT & Future, Korea. The work at Kyoto was supported by JSPS KAKENHI Grant Numbers 25220802 and 25620031. S. O. acknowledges a JSPS fellowship. The quantum calculations were performed using the supercomputing resources of the Korea Institute of Science and Technology Information (KISTI).
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry