title: A Molecular Chameleon: Reversible pH- and Cation-Induced Control of the Optical Properties of Phthalocyanine-Based Complexes in the Visible and Near-Infrared Spectral Ranges.
abstract: A series of novel nonperipherally substituted tetra-15-crown-5-dibutoxyoxanthrenocyanines (H2, Mg, Zn), acting as chameleons with the unique properties of switchable absorption and emission in the near-infrared (NIR) spectral range have been synthesized and characterized by X-ray diffraction. The attachment of 15-crown-5-α-dibutoxyoxanthreno moieties to phthalocyanine is responsible for the high solubility of the resulting molecules and the red shift of the Q band to the NIR region and offers a unique possibility for postsynthetic modification of the optical properties of the molecules. Both aggregation of phthalocyanine and its participation in an acid-base equilibrium strongly alter their optical properties. For example, the absorption of complexes can be reversibly tuned from 686 up to 1028 nm because of the cation-induced formation of supramolecular dimers or subsequent protonation of meso-N atoms orf macrocycle, in contrast to peripherally substituted tetra-15-crown-5-phthalocyanines without oxanthrene moieties. The reversibility of these processes can be controlled by the addition of [2.2.2]cryptand or amines. All investigated compounds exhibit fluorescence with moderate quantum yield, which can also be switched between the ON and OFF states by the action of similar agents.
authors.affiliation: Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , Leninskii pr. 31, bldg. 4, Moscow 119071, Russia.
authors.forename: Evgeniya A
authors.initials: EA
authors.lastname: Safonova
authors.affiliation: Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , Leninskii pr. 31, bldg. 4, Moscow 119071, Russia.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Martynov
authors.affiliation: Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences , Leninskii pr. 31, Moscow 119991, Russia.
authors.forename: Sergey E
authors.initials: SE
authors.lastname: Nefedov
authors.affiliation: Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , Leninskii pr. 31, bldg. 4, Moscow 119071, Russia.|Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences , Leninskii pr. 31, Moscow 119991, Russia.
authors.forename: Gayane A
authors.initials: GA
authors.lastname: Kirakosyan
authors.affiliation: Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , Leninskii pr. 31, bldg. 4, Moscow 119071, Russia.|Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences , Leninskii pr. 31, Moscow 119991, Russia.
authors.forename: Yulia G
authors.initials: YG
authors.lastname: Gorbunova
authors.affiliation: Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , Leninskii pr. 31, bldg. 4, Moscow 119071, Russia.|Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences , Leninskii pr. 31, Moscow 119991, Russia.
authors.forename: Aslan Yu
authors.initials: AY
authors.lastname: Tsivadze