Heterocorroles: corrole analogues containing heteroatom(s) in the core or at a meso-position

Corroles are 18 aromatic macrocyclic systems having one direct pyrrole-pyrrole linkage leading to a contracted cavity compared to porphyrins. Corroles exhibit contrasting coordination chemistry and properties compared to porphyrins. Structural modification of corroles by introducing a heteroatom in their aromatic conjugation circuit i.e., either in the core or at a meso position leads to a new class of corrinoids called heterocorroles. The core modification strategy includes replacing one or two core nitrogen atom(s) with O, S or C atoms and meso-modification involves replacing the meso-carbon atom at the 10-position with NH, NR, O, S, Se or Si atoms. This review article presents an overview of the progress in heterocorrole chemistry including their syntheses, key structural aspects and properties

Synthesis and properties of Oxasmaragdyrins containing one Five-membered Heterocycle at Meso-position

The oxasmaragdyrins containing one five membered heterocycle such as pyrrole, thiophene and furan in place of one of the meso-phenyl group were synthesized by acid-catalyzed oxidative coupling reaction of meso-heterocycle substituted dipyrromethane with 16-oxatripyrrane in the presence of catalytic amount of trifluoroacetic acid followed by oxidation with DDQ. The smaragdyrin macrocycles containing one five-membered heterocycle at meso-position were characterized by HR-MS and detailed 1D and 2D NMR studies. The absorption and fluorescence studies revealed that the presence of five membered heterocycle at meso-position of smaragdyrin resulted in bathochromic shifts in absorption and emission bands with slight reduction in quantum yields compared to smraragdyrin macrocycle containing six membered meso-phenyl groups. The electrochemical studies revealed that the meso-heterocycle smaragdyrins are electron deficient compared to meso-phenyl smaragdyrins

<i>Meso</i>-pyrrolyl BODIPY based colorimetric optical sensor for Cu2+ ions

A simple meso-pyrrolyl BODIPY-Schiff base conjugate was synthesized by reacting ([Formula: see text]-formylpyrrolyl) BODIPY with 2-aminophenol in ethanol at reflux followed by recrystallization from CH2Cl2/petroleum ether, affording the conjugate in 72% yield. The conjugate was thoroughly characterized by HR-MS, 1D and 2D NMR and X-ray crystallographic techniques. The X-ray structure of the meso-pyrrolyl BODIPY-Schiff base conjugate revealed that the meso-pyrrole and the phenyl substituents were deviated by an angle of [Formula: see text] and [Formula: see text], respectively, from the plane of the BF2-dipyrrin core. The absorption spectrum of the conjugate was similar to the ([Formula: see text]-formylpyrrolyl) BODIPY with a strong absorption band at 508 nm, whereas the fluorescence of the ([Formula: see text]-formylpyrrolyl) BODIPY was completely quenched in the BODIPY-Schiff base conjugate. Furthermore, cation sensing studies revealed that the conjugate has a specific sensing ability for the Cu(II) ion even in the presence of the other metal ions, as verified by the visual, absorption and mass spectral studies. The DFT optimized structure revealed that the Cu(II) ion was bound to pyrrolic nitrogen, imine nitrogen, phenolic oxygen and two water molecules in a distorted square pyramidal fashion. TD-DFT studies accounted well for the absorption spectra of the BODIPY-Schiff base conjugate and its Cu[Formula: see text] bound complex. </jats:p