ABSTRACT
An expanded porphyrinoid has been obtained by a simple ring expansion from a contracted porphyrinoid, namely corrole. Spectroscopic, structural, and computational investigations reveal peculiar π-conjugation and geometry. The effect of extended π-conjugation is evident from perturbed redox behavior and photophysical properties. Owing to the strong diatropic ring current of the corrole and cross-conjugation, the molecule exhibits a non-aromatic nature for the expanded π-circuit, as evident from NMR studies.
ABSTRACT
Anchoring a BODIPY onto Ga(III)corrole via a meso-ß linkage facilitated PeT in polar solvents, which quenched the fluorescence, and is further confirmed by electrochemical studies. The triad exhibits unprecedented crystal emission, which is not known for a corrole derivative, due to unique packing. Compound 4 hosts the first example of a novel B-FâââF interaction as well.
ABSTRACT
A free-base and its Cu(III) derivative of bichromophoric meso-ß linked corrole-BODIPY dyad were synthesized and structurally characterized by single crystal X-ray diffraction (XRD). Both corrole and BODIPY fragments maintained respective ground state electronic isolation despite their connection through a single bond due to a tilted orientation as observed by XRD. This was further supported by UV-vis and cyclic voltammetric studies. The Cu(III)-metalated dyad exhibits temperature-dependent paramagnetic behavior as observed in the variable temperature (1)H NMR due to the presence of a Cu(II)-corrole-π-cation radical. Importantly, the free-base exhibits complete fluorescence quenching probably due to photoinduced electron transfer to a low lying charge separated state. Interestingly, emission was regained upon addition of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) due to the deprotonation of corrole. The "turn on" fluorescence behavior and the presence of acidic NH protons were further exploited toward basic anion sensing utility.
