Combined Experimental and Theoretical Investigations on Optical Activities of Möbius Aromatic and Möbius Antiaromatic Hexaphyrin Phosphorus Complexes
- 9 June 2016
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry A
- Vol. 120 (24), 4241-4248
- https://doi.org/10.1021/acs.jpca.6b03978
Abstract
Intrinsically chiral Möbius aromatic [28]hexaphyrin monophosphorus(V) and Möbius antiaromatic [30]hexaphyrin bisphosphorus(V) complexes have been optically resolved and their absolute configurations (ACs) were determined by combined experimental and theoretical investigations on their circular dichroisms (CDs). First elutes in chiral HPLC exhibited strong positive Cotton effects (CEs) at the B-band, characteristic for the ML configurations in their Möbius strips. Weak CEs at the Q-band, if attainable, complemented their AC assignment. The whole CD pattern and intensity were well reproduced by time-dependent approximate coupled cluster theory using model systems that omit five outward meso-aryl substituents (inward-meso-retained model), providing a solid basis for AC assignment. The cost efficient TD-DFT method with appropriate functionals for fully substituted (nontruncated) complexes well reproduced CEs around the B-band (but less satisfactory at the Q-band), also allows the rapid AC estimation for their Möbius strips. Observed difference in CDs between aromatic and antiaromatic hexaphyrins were better interpreted by their shifts in energy levels and altered interactions of relevant molecular orbitals, rather than small differences in Möbius geometries nor aromatic/antiaromatic character, despite the correlations recently claimed in planar π-systems.Keywords
Funding Information
- Toyota Motor Corporation
- Japan Society for the Promotion of Science (15H010870, 15H037790, 15K13642, 25220802, 26620081)
- Japan Science and Technology Agency (MP27215667549)
- Hitachi
- Iketani Science and Technology Foundation
- Shorai Foundation for Science and Technology
- Tokuyama Corporation
- Izumi Science and Technology Foundation
This publication has 43 references indexed in Scilit:
- Aromaticity and Optical ActivityJournal of the American Chemical Society, 2015
- Reversal of Hückel (anti)aromaticity in the lowest triplet states of hexaphyrins and spectroscopic evidence for Baird's ruleNature Chemistry, 2015
- Excited State Aromaticity and Antiaromaticity: Opportunities for Photophysical and Photochemical RationalizationsChemical Reviews, 2014
- Circular dichroism: electronicWIREs Computational Molecular Science, 2011
- Figure Eights, Möbius Bands, and More: Conformation and Aromaticity of PorphyrinoidsAngewandte Chemie, 2011
- Expanded Porphyrins: Intriguing Structures, Electronic Properties, and ReactivitiesAngewandte Chemie, 2011
- Expanded porphyrins and aromaticityChemical Communications, 2011
- Möbius aromaticity and antiaromaticity in expanded porphyrinsNature Chemistry, 2009
- Expanded Porphyrins and Their HeterologsChemical Reviews, 1997
- Circular Dichroism and the Conformational Analysis of BiomoleculesPublished by Springer Science and Business Media LLC ,1996