Stepwise Fusion of Porphyrin β,β′-Pyrrolic Positions to Imidazole Rings

Abstract

A strategy for the stepwise annulation of pyrrolic rings of a porphyrin to imidazole rings is presented. Mono(imidazole), Janus and corner bis(imidazole), T-shaped tris(imidazole), and tetrakis(imidazole) porphyrins have been synthesized and characterized.

Porphyrins Fused to N‐Heterocyclic Carbenes (NHCs): Modulation of the Electronic and Catalytic Properties of NHCs by the Central Metal of the Porphyrin

“…The porphyrins fused to an imidazole ring, 2 Ni and 2 NiMe, were obtained by the stepwise functionalization of a Ni II meso-tetraarylporphyrin complex (meso-aryl = 4-tBuPh). [13] Free-base imidazoles 2 H2 and 2 H2Me were obtained by treating the corresponding Ni II complexes 2 Ni and 2 NiMe with a mixture of H 2 SO 4 and trifluoroacetic acid (TFA). Interestingly, 2 H2 and 2 H2Me appeared to be air-sensitive both in solution and in the solid state, and were slowly oxidized to free-base secochlorins 4 H2 and 4 H2Me (Scheme 2).…”

Binding modes of a core-extended metalloporphyrin to human telomeric DNA G-quadruplexes

“…The corresponding porphyrin fused to four imidazoles was used as a starting material and its synthesis was previously reported by one of us. 31 The porphyrin fused to four imidazoles (18 mg, 0.0107 × 10 −3 mmol) was dissolved in DMF (5 mL) and an excess of iodomethane (1 mL) was added. The reaction mixture was vigorously stirred under an atmosphere of argon for 48 hours.…”

“…The Ni II -TImidP4 geometry was extrapolated from the crystalline structure of the porphyrin bis(imidazolium) salt (counter anions = BF 4 − ) where the two imidazolium rings are fused to two neighboring pyrrole units, similarly to the procedure previously reported for the parent bis(imidazole). 31 The optimization steps were performed within C 2v symmetry. Both singlet and triplet states have been considered.…”

Imidazoporphyrins as supramolecular tectons: synthesis and self-assembly of zinc 2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate

“…5 Therefore, imidazo [4,5-b]porphyrins are of interest for the preparation of the modular porphyrin derivatives, arrays and conjugates. For example, imidazo [4,5-b]porphyrins bearing N-heterocyclic carbene fragment (NHC) at the periphery of the macrocycle [6][7][8][9][10][11] were prepared from derivatives unsubstituted at position 2 of the imidazole ring which are available by the condensation of β,β'-diaminoporphyrins and orthoformate. 10,11 The rhodium(II) and palladium(II) complexes with these porphyrin-modified NHCs exhibit remarkable catalytic activity in the ring-opening polymerization of L-lactide and the Mizoroki-Heck crosscoupling reaction, respectively.…”

“…For example, imidazo [4,5-b]porphyrins bearing N-heterocyclic carbene fragment (NHC) at the periphery of the macrocycle [6][7][8][9][10][11] were prepared from derivatives unsubstituted at position 2 of the imidazole ring which are available by the condensation of β,β'-diaminoporphyrins and orthoformate. 10,11 The rhodium(II) and palladium(II) complexes with these porphyrin-modified NHCs exhibit remarkable catalytic activity in the ring-opening polymerization of L-lactide and the Mizoroki-Heck crosscoupling reaction, respectively. 12,13 Fused porphyrins containing a 2-functionalized imidazole ring can be easily prepared by the condensation of β-dioxochlorins with aromatic aldehydes in the presence of ammonium acetate.…”