Nickel-Catalyzed Aminoxylation of Inert Aliphatic C(sp³)–H Bonds with Stable Nitroxyl Radicals under Air: One-Pot Route to α‑Formyl Acid Derivatives

Nickel-catalyzed aminoxylation of an unactivated C­(sp³)–H bond with a stable nitroxyl radical has been accomplished for the first time to offer various <i>N</i>-alkoxyamine derivatives, which further enables a one-pot approach to α-formyl acid derivatives. The aminoxylation process reported also provides direct evidence for the oxidative addition of a cyclometallic intermediate with a free radical, which is helpful for the reaction-mechanism study in transition-metal-catalyzed functionalization of inert C­(sp³)–H bonds

Rhodium-Catalyzed Oxidative Coupling of Benzoic Acids with Terminal Alkynes: An Efficient Access to 3‑Ylidenephthalides

Herein we disclose the first example of transition-metal-catalyzed oxidative coupling/annulation of simple benzoic acids with terminal alkynes via C–H activation. A range of aromatic carboxylic acids and terminal alkynes have been found to be viable substrates in this reaction, providing a simple and efficient method for the synthesis of diverse 3-ylidenephthalides with complete <i>Z</i> selectivity

Copper- or Nickel-Enabled Oxidative Cross-Coupling of Unreactive C(sp³)–H Bonds with Azole C(sp²)–H Bonds: Rapid Access to β‑Azolyl Propanoic Acid Derivatives

β-Azolyl propanoic acid derivatives are frequently found in biologically active molecules and pharmaceuticals. Here, we report the oxidative heteroarylation of unactivated C­(sp³)–H bonds with azole C­(sp²)–H bonds via copper or nickel catalysis with the aid of removable bidentate auxiliary, which provides a rapid pathway to β-azolyl propanoic acid derivatives. A variety of azoles such as oxazole, benzoxazole, thiazole, benzothiazoles, benzimidazole, purine, and even [1,2,4]­triazolo­[1,5-<i>a</i>]­pyrimidine could be engaged in this protocol

Rhodium-Catalyzed Oxidative Coupling of Benzoic Acids with Terminal Alkynes: An Efficient Access to 3‑Ylidenephthalides

Herein we disclose the first example of transition-metal-catalyzed oxidative coupling/annulation of simple benzoic acids with terminal alkynes via C–H activation. A range of aromatic carboxylic acids and terminal alkynes have been found to be viable substrates in this reaction, providing a simple and efficient method for the synthesis of diverse 3-ylidenephthalides with complete <i>Z</i> selectivity

Novel Ruthenium Sensitizers with a Phenothiazine Conjugated Bipyridyl Ligand for High-Efficiency Dye-Sensitized Solar Cells

Two efficient ruthenium sensitizers with a phenothiazine-modified bipyridine as an ancillary ligand, coded <b>SCZ-1</b> and <b>SCZ-2</b>, have been developed as dyes in dye-sensitized solar cells (DSSCs). Both sensitizers exhibit low-energy metal-to-ligand charge transfer (MLCT) bands centered at 539 nm with high molar extinction coefficients of 1.77 × 10⁴ M^–1 cm^–1 for <b>SCZ-1</b> and 1.66 × 10⁴ M^–1 cm^–1 for <b>SCZ-2</b>, which are significantly higher than the corresponding value for the reference <b>N719</b> (1.27 × 10⁴ M^–1 cm^–1), indicating that the light-harvesting capacity of ruthenium sensitizers can be reinforced by introducing phenothiazine moieties into the bipyridine ligand. Under AM 1.5G irradiation (100 mW cm^–2), <b>SCZ</b>-<b>1</b> and <b>SCZ-2</b> sensitized DSSC devices show impressive power conversion efficiencies (PCE) up to 10.4% by using of iodide-based electrolytes, which exceeds that of <b>N719</b> (9.9%) under the same conditions. Both of the open circuit voltage (<i>V</i>_OC) and fill factor (FF) of <b>SCZ</b>-sensitized solar cells approximate to those of <b>N719</b>-sensitized cell. The relatively higher efficiencies of the <b>SCZ</b>-sensitized cells than that of <b>N719</b>-sensitized cell come from their higher short-circuit photocurrent density (<i>J</i>_SC), which may be mainly attributed to the high absorption coefficient. The absorption spectrum and device efficiency of <b>SCZ-1</b> are both quite close to those of <b>SCZ-2</b>, suggesting that the difference in alkyl chains on the N atom of phenothiazine is not a decisive factor in affecting the photovoltaic performance of dyes