In:
Journal of Physical Organic Chemistry, Wiley, Vol. 31, No. 8 ( 2018-08)
Abstract:
An overview of magnetic circular dichroism (MCD) spectroscopy of π‐electron systems derived from a 4 N ‐electron perimeter is provided, with emphasis on the hypothetical parent cycloocta‐1,3,5,7‐tetraene of D 8 h symmetry ( 1 ) and its D 4 h symmetry derivatives. UV‐visible absorption and MCD spectra of 2 , a D 4 h 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 8 h and unaromatic D 4 h 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.
Type of Medium:
Online Resource
ISSN:
0894-3230
,
1099-1395
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
1475025-9
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