Magnetic circular dichroism of an unaromatic planar [8]annulene

0492379 - ÚOCHB 2019 RIV GB eng J - Článek v odborném periodiku
Wen, Jin - Uto, T. - Chalupský, Jakub - Casher, D. L. - Raabe, G. - Fleischhauer, J. - Yanai, T. - Tsuji, H. - Komatsu, K. - Michl, Josef
Magnetic circular dichroism of an unaromatic planar [8]annulene.
Journal of Physical Organic Chemistry. Roč. 31, č. 8 (2018), č. článku e3854. ISSN 0894-3230. E-ISSN 1099-1395
Institucionální podpora: RVO:61388963
Klíčová slova: excited states * extended multistate complete active space second-order perturbation theory * magnetic circular dichroism * perimeter model * planar cyclooctatetraene
Obor OECD: Physical chemistry
Impakt faktor: 1.530, rok: 2018

An overview of magnetic circular dichroism (MCD) spectroscopy of pi-electron systems derived from a 4N-electron perimeter is provided, with emphasis on the hypothetical parent cycloocta-1,3,5,7-tetraene of D-8h symmetry (1) and its D-4h symmetry derivatives. UV-visible absorption and MCD spectra of 2, D-4h, symmetric cycloocta-1,3,5,7-tetraene planarized by the effect of 4 bicyclo[2.1.1]hexeno units fused to its 8-membered ring, are reported and interpreted. The perimeter model is applied to obtain an understanding of the nature of electronic states in 1 and 2 and to predict general trends in the spectra. The electronic excitation patterns are found to be different in the antiaromatic D-8h and unaromatic D-4h species, and their states cannot be unequivocally correlated. The results of time-dependent density functional theory and extended multistate complete active space second-order perturbation theory (XMS-CASPT2) computations agree with the algebraic perimeter model analysis and reproduce the spectra of 2 well, including three of the four observed MCD signs of A and B terms.
Trvalý link: http://hdl.handle.net/11104/0285938