Rhodium(III) and Iridium(III) Bipyricorrole Complexes: Syntheses, Structures, and Properties.

Rhodium(III) and iridium(III) bipyricorrole complexes have been unprecedentedly reported. Single-crystal X-ray diffraction studies unambiguously evinced the molecular structures of metal complexes in octahedral geometry. The monoanionic platform of bipyricorrole effectively stabilizes metal ions in their higher oxidation states. It is worth mentioning that the fluorescence quantum yield of the rhodium(III) complex is 3-fold higher than that of free-base bipyricorrole.

First example of a modular porphyrinoid assembly capable of stabilizing different metal ions in a single molecular scaffold.

We report the synthesis and characterization of porphyrin-corrole-porphyrin (Por-Cor-Por) hybrids directly linked at the meso-meso positions for the first time. The stability and solubility of the trimer are carefully balanced by adding electron-withdrawing substituents to the corrole ring and sterically bulky groups on the porphyrins. The new hybrids are capable of stabilizing more than one metal ion in a single molecular scaffold. The versatility of the triad has been demonstrated by successfully stabilizing homo- (Ni) and heterotrinuclear (Ni-Cu-Ni) coordination motifs. The solid-state structure of the NiPor-CuCor-PorNi hybrid was revealed by single-crystal X-ray diffraction studies. The Ni(II) porphyrins are significantly ruffled and tilted by 83° from the plane of corrole. The robustness of the synthesized hybrids was reflected in the electrochemical investigations and the redox behaviour of the hybrids show that the oxidation processes are mostly corrole-centred. In particular it is worth noting that the Por-Cor-Por hybrid can further be manipulated due to the presence of substituent-free meso-positions on both the terminals.

Camphorsulfonic acid catalysed facile tandem double Friedlander annulation protocol for the synthesis of phenoxy linked bisquinoline derivatives and discovery of antitubercular agents.

A series of phenoxy linked bisquinoline derivatives were synthesised from the Friedlander annulation of 2-(4-acetylphenoxy)-1-aryl-1-ethanones with 2-aminobenzophenone in good yields using (±)-camphor-10-sulfonic acid (CSA) as the catalyst. These compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB) and among the 23 compounds screened, 2-(3-bromophenyl)-6-chloro-3-[4-(6-chloro-4-phenyl-2-quinolyl)phenoxy]-4-phenylquinoline (3q) and 2-(4-bromophenyl)-6-chloro-3-[4-(6-chloro-4-phenyl-2-quinolyl)phenoxy]-4-phenylquinoline (3o) were found to be the most active compounds with MIC of 1.1 and 2.2 µM against MTB. The cytotoxic effects against mouse fibroblasts (NIH 3T3) in vitro were evaluated for 3o and 3q, which displayed no toxic effects against mouse fibroblast cell line NIH 3T3.

Alkali metal ion binding using cyclic polyketones.

Cyclic oligoketones composed of 3,3-dimethylpentane-2,4-diones showed crown ether-like alkali metal ion binding behavior with association constants up to 1.7 × 104 M-1 in chloroform/acetonitrile (v/v, 9/1). The binding properties have been used for catalysis in the Finkelstein reaction in a low-polarity solvent. Furthermore, novel ion-binding hosts were generated by terminal functionalization of linear polyketones.

A tris-(manganese(iii))corrole-porphyrin-corrole triad: synthesis, characterization and catalytic epoxidation.

A homotrimetallic manganese(iii) corrole-porphyrin-corrole triad has been synthesized and structurally characterized. Corrole and porphyrin rings in the free base corrole-porphyrin-corrole triad are found to be roughly perpendicular to each other having a dihedral angle of 83° in the solid state. A dihedral angle of nearly 67° was found between Mn(iii)-corroles and Mn(iii)-porphyrin rings in the manganese triad complex, 1-Mn. The absorption spectrum of the manganese triad was observed to be the sum of the absorptions from manganese corrole and manganese porphyrin. The catalytic activity of the manganese triad complex was investigated for the epoxidation of styrene using iodobenzene diacetate as an oxygen source. Preliminary results obtained showed the superior activity of the manganese triad as an oxidation catalyst as compared to the respective monomer catalysts. Moreover, product yield in the oxidation of styrene catalyzed by the manganese triad was found to be higher than that of the combined activity of both monomers taken in same equivalence. The reason behind this higher yield may be attributed to an increased local concentration of the catalytic centers at the reaction site.