Sustainable Pd-Catalyzed Direct Arylation of Thienyl Derivatives with (Hetero)aromatic Bromides under Air in Deep Eutectic Solvents

Abstract

An optimized protocol for the Pd-catalyzed direct arylation of 3,4-ethylenedioxythiophene (EDOT) and other substituted thiophenes with (hetero)aromatic bromides in a deep eutectic solvent made of a mixture of choline chloride/glycerol (1:2) is presented. The coupling reactions have been successfully run under air, in nonanhydrous conditions, using PdCl 2 as a palladium source, with a catalyst loading as low as 1 mol %. The adjustment of each reaction component allowed finding robust conditions for the introduction of both electron-poor and electronrich (hetero)aryl bromides with moderate-to-high yields. The sustainability of the protocol was established through calculations of green metrics, such as Eco-scale and E-factor, and compared with the literature, when possible. Remarkably, such procedure can be successfully applied for the simple preparation of conjugated organic compounds with potential applications in optoelectronics, as we have shown, by obtaining two molecules previously reported as a hole transport material for perovskite solar cells and the final intermediate of a photosensitizer for dye-sensitized solar cells.

Novel Two-Dimensional Graphdiyne-Derived Additive for Stable Inverted Perovskite Solar Cells

“…The reaction was conducted at 80 °C for 4 h under stirring. Finally, a transparent liquid with a certain viscosity was formed, denoted as DES . The DES was diluted with 80 mL of N , N -dimethylformamide (DMF) to afford a DES solution.…”

Deep Eutectic Solvents as à-la-Carte Medium for Transition-Metal-Catalyzed Organic Processes

“…More recently, ChCl:glycerol (1:2) has been proposed as a better solvent for the arylation of thiophene derivatives. In this case, PdCl 2 and P( o -MeOPh) 3 were used as catalysts, employing pivalic acid as an additive and potassium carbonate as a base with the reaction between aryl bromides and thiophene derivatives being stirred at 110 °C for 24 h. Good-to-excellent yields were obtained, especially when electron-poor aromatic bromides were employed, yielding products with application in the photovoltaic field ( Figure 31 , Table 4 , entry 5) [ 91 ].…”

Theoretical Design, Synthesis, Solvatochromic Studies and Non‐Linear Optical Properties of 3,4‐Ethylenedioxythiophene and 3,4‐ Propylenedioxythiophene based Copolymers

“…The EDOT and PRDOT monomers are coupled with naphthalene unit by direct‐arylation polymerization method achieved by the direct coupling between the C−H activated thiophene rings by the palladium catalyst and aryl halides [39–41] . Direct arylation method of polymerization enables the production of conjugated polymers with atom economy [42]…”

“…[35][36][37][38] The EDOT and PRDOT monomers are coupled with naphthalene unit by direct-arylation polymerization method achieved by the direct coupling between the CÀ H activated thiophene rings by the palladium catalyst and aryl halides. [39][40][41] Direct arylation method of polymerization enables the production of conjugated polymers with atom economy. [42] The present manuscript details the synthesis and characterization of two copolymers, Poly (3,4-ethylenedioxythiophenenaphthalene) [(P(EDOT-NA)] and Poly(3,4propylenedioxythiophene-naphthalene)[P(PRDOT-NA)].…”