1 research outputs found
Absorption and Fluorescence Features of an Amphiphilic <i>meso</i>-Pyrimidinylcorrole: Experimental Study and Quantum Chemical Calculations
Corroles
are emerging as an important class of macrocycles with
numerous applications because of their peculiar photophysical and
metal chelating properties. <i>meso</i>-Pyrimidinylcorroles
are easily deprotonated in certain solvents, which changes their absorption
and emission spectra as well as their accessible supramolecular structures.
To enable control over the formation of supramolecular structures,
the dominant corrole species, i.e., the deprotonated form or one of
the two NH-tautomers, needs to be identified. Therefore, we focus
in the present article on the determination of the UV–vis spectroscopic
properties of the free-base NH-tautomers and the deprotonated form
of a new amphiphilic <i>meso</i>-pyrimidinylcorrole that
can assemble to supramolecular structures at heterointerfaces as utilized
in the Langmuir–Blodgett and liquid–liquid interface
precipitation techniques. After quantification of the polarities of
the free-base NH-tautomers and the deprotonated form by means of quantum
chemically derived electrostatic potential distributions at the corroles’
van der Waals surfaces, the preferential stabilization of (some of)
the considered species in solvents of different polarity is identified
by means of absorption spectroscopy. For the solutions with complex
mixtures of species, we applied fluorescence excitation spectroscopy
to estimate the relative weights of the individual corrole species.
This technique might also be applied to identify dominating species
in molecularly thin films directly on the subphase’ surface
of Langmuir–Blodgett troughs. Supported by quantum chemical
calculations we were able to differentiate between the spectral signatures
of the individual NH-tautomers by means of fluorescence excitation
spectroscopy