Synthesis and Characterization of Novel Fused Porphyrinoids Based on Cyclic Carbazole[2]indolones

The carbazole- and indolone-based porphyrinoids <b>3</b> and <b>4</b> were synthesized by stepwise transition-metal-catalyzed coupling reactions. Palladium metalation of <b>4</b> produced <b>4Pd</b>, which exhibits near-infrared absorption

Synthesis and Characterization of Novel Fused Porphyrinoids Based on Cyclic Carbazole[2]indolones

The carbazole- and indolone-based porphyrinoids <b>3</b> and <b>4</b> were synthesized by stepwise transition-metal-catalyzed coupling reactions. Palladium metalation of <b>4</b> produced <b>4Pd</b>, which exhibits near-infrared absorption

Synthesis of Carbazole-Based Selenaporphyrin <i>via</i> Annulation

Cu(I)-mediated alkoxylation of doubly 1,3-butadiyne-bridged carbazole dimer <b>1</b>, followed by acid-catalyzed cyclization, provided furan-bridged carbazole dimer <b>3</b>, while annulation reaction of <b>1</b> with selenium in the presence of hydrazine monohydrate provided selenophene-bridged carbazole dimer <b>5a</b>. Oxidation of isophlorin <b>5a</b> afforded carbazole-based selenaporphyrin <b>5b</b>, which possessed distinct aromaticity and produced intensified and red-shifted absorption bands in the near-IR region

Synthesis of Carbazole-Based Selenaporphyrin <i>via</i> Annulation

Cu(I)-mediated alkoxylation of doubly 1,3-butadiyne-bridged carbazole dimer <b>1</b>, followed by acid-catalyzed cyclization, provided furan-bridged carbazole dimer <b>3</b>, while annulation reaction of <b>1</b> with selenium in the presence of hydrazine monohydrate provided selenophene-bridged carbazole dimer <b>5a</b>. Oxidation of isophlorin <b>5a</b> afforded carbazole-based selenaporphyrin <b>5b</b>, which possessed distinct aromaticity and produced intensified and red-shifted absorption bands in the near-IR region

Carbazole-Based Boron Dipyrromethenes (BODIPYs): Facile Synthesis, Structures, and Fine-Tunable Optical Properties

Carbazole-based BODIPYs were synthesized in three steps using an organometallic approach consisting of sequential Ir-catalyzed borylation, Suzuki–Miyaura coupling, and boron complexation. Various substituents were introduced into the carbazole moiety, and large substituent effects were confirmed by means of absorption spectroscopy, cyclic voltammetry, and DFT calculations. Dibenzocarbazoles were also converted into the corresponding BODIPYs

Effective π‑Extension of Carbazole-Based Thiaporphyrins by Peripheral Phenylethynyl Substituents

Several tetrakis(phenylethynyl)- and (phenylethynylphenylethynyl)-substituted carbazole-based thiaporphyrins were synthesized. These π-extended porphyrins display remarkably intensified and red-shifted absorption bands in the NIR region up to 1126 nm due to perturbation by the phenylethynyl substituents

Synthesis of Carbazole-Based Selenaporphyrin <i>via</i> Annulation

Cu(I)-mediated alkoxylation of doubly 1,3-butadiyne-bridged carbazole dimer <b>1</b>, followed by acid-catalyzed cyclization, provided furan-bridged carbazole dimer <b>3</b>, while annulation reaction of <b>1</b> with selenium in the presence of hydrazine monohydrate provided selenophene-bridged carbazole dimer <b>5a</b>. Oxidation of isophlorin <b>5a</b> afforded carbazole-based selenaporphyrin <b>5b</b>, which possessed distinct aromaticity and produced intensified and red-shifted absorption bands in the near-IR region

Intramolecular Electronic Coupling in the Thiophene-Bridged Carbazole-Based Diporphyrin

The Glaser coupling reaction of ethynyl-substituted carbazole-based isophlorins provided butadiyne-bridged dimers, which were transformed into the thiophene-bridged dimers via the annulation reaction. Oxidation of these isophlorin dimers afforded carbazole-based diporphyrins. Notable electronic interactions in the diporphyrins have been confirmed by means of UV/vis–near-infrared (NIR) absorption spectroscopy, cyclic voltammetry (CV) measurements, and density functional theory (DFT) calculations

Correction to “Bifunctional Porphyrin Catalysts for the Synthesis of Cyclic Carbonates from Epoxides and CO₂: Structural Optimization and Mechanistic Study”

Correction to “Bifunctional Porphyrin Catalysts for the Synthesis of Cyclic Carbonates from Epoxides and CO₂: Structural Optimization and Mechanistic Study

Bifunctional Porphyrin Catalysts for the Synthesis of Cyclic Carbonates from Epoxides and CO₂: Structural Optimization and Mechanistic Study

We prepared bifunctional Mg^II porphyrin catalysts <b>1</b> for the solvent-free synthesis of cyclic carbonates from epoxides and CO₂. The activities of <b>1d</b>, <b>1h</b>, and <b>1i</b>, which have Br^–, Cl^–, and I^– counteranions, respectively, increased in the order <b>1i</b> < <b>1h</b> < <b>1d</b>. Catalysts <b>1d</b> and <b>1j</b>–<b>m</b>, which bear four tetraalkylammonium bromide groups with different alkyl chain lengths, showed comparable but slightly different activities. Based on the excellent catalyst <b>1d</b>, we synthesized Mg^II porphyrin <b>1o</b> with eight tetraalkylammonium bromide groups, which showed even higher catalytic activity (turnover number, 138,000; turnover frequency, 19,000 h^–1). The catalytic mechanism was studied by using <b>1d</b>. The yields were nearly constant at initial CO₂ pressures in the 1–6 MPa range, suggesting that CO₂ was not involved in the rate-determining step in this pressure range. No reaction proceeded in supercritical CO₂, probably because the epoxide (into which the catalyst dissolved) dissolved in and was diluted by the supercritical CO₂. Experiments with ¹⁸O-labeled CO₂ and D-labeled epoxide suggested that the catalytic cycle involved initial nucleophilic attack of Br^– on the less hindered side of the epoxide to generate an oxyanion, which underwent CO₂ insertion to afford a CO₂ adduct; subsequent intramolecular ring closure formed the cyclic carbonate and regenerated the catalyst. Density functional theory calculations gave results consistent with the experimental results, revealing that the quaternary ammonium cation underwent conformational changes that stabilized various anionic species generated during the catalytic cycle. The high activity of <b>1d</b> and <b>1o</b> was due to the cooperative action of the Mg^II and Br^– and a conformational change (induced-fit) of the quaternary ammonium cation