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New Styryl Phenanthroline Derivatives as Model D−π−A−π−D Materials for Non‐Linear Optics
Author(s) -
Bonaccorso Carmela,
Cesaretti Alessio,
Elisei Fausto,
Mencaroni Letizia,
Spalletti Anna,
Fortuna Cosimo G.
Publication year - 2018
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.201800391
Subject(s) - solvatochromism , chromophore , photochemistry , hyperpolarizability , excited state , phenanthroline , intramolecular force , fluorescence , chemistry , two photon absorption , absorption (acoustics) , photoexcitation , ultrafast laser spectroscopy , femtosecond , bodipy , acceptor , moiety , materials science , optics , molecule , crystallography , organic chemistry , polarizability , physics , atomic physics , laser , composite material , condensed matter physics
Four novel push−pull systems combining a central phenanthroline acceptor moiety and two substituted benzene rings, as a part of the conjugated π‐system between the donor and the acceptor moieties, have been synthetized through a straightforward and efficient one‐step procedure. The chromophores display high fluorescence and a peculiar fluorosolvatochromic behaviour. Ultrafast investigation by means of state−of−the−art femtosecond‐resolved transient absorption and fluorescence up‐conversion spectroscopies allowed the role of intramolecular charge transfer (ICT) states to be evidenced, also revealing the crucial role played by both, the polarity and proticity of the medium on the excited state dynamics of the chromophores. The ICT processes, responsible for the solvatochromism, also lead to interesting non‐linear optical (NLO) properties: namely great two photon absorption cross‐sections (hundreds of GM), investigated by the Two Photon Excited Fluorescence (TPEF) technique, and large second order hyperpolarizability coefficients, estimated through a convenient solvatochromic method.