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Impact of Ion‐Pairing Effects on Linear and Nonlinear Photophysical Properties of Polymethine Dyes **
Author(s) -
Pascal Simon,
Chi SanHui,
Perry Joseph W.,
Andraud Chantal,
Maury Olivier
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000731
Subject(s) - cyanine , chemistry , delocalized electron , absorption (acoustics) , counterion , dipole , photochemistry , ion , molecular electronic transition , electronic structure , pairing , atomic electron transition , absorption spectroscopy , two photon absorption , chemical physics , molecular physics , computational chemistry , molecule , fluorescence , physics , condensed matter physics , organic chemistry , optics , laser , superconductivity , astronomy , spectral line
Abstract The two‐photon absorption (2PA) and photophysics of heptamethine dyes featuring cyanine or dipolar electronic structures have been compared for the first time. The perfectly delocalized c yanine system is classically characterized by a two‐photon transition matching the vibronic component of its lower energy absorption band. The dipolar species is generated by ion‐pairing with a hard counterion in a non‐dissociating solvent and displays significant modifications oft he optical properties, including a significant hypochromic shift of absorption, weaker emission and 2PA matching the lower energy transition, thus revealing symmetry breaking within the polymethine electronic structure.