ortho‐Phenylene‐Bridged Hybrid Nanorings of 2,5‐Pyrrolylenes and 2,5‐Thienylenes

Abstract

Hybrid nanorings composed of 2,5-pyrrolylene, 2,5thienylene, and bridging ortho-phenylene were synthesized by strategic cross-coupling reactions, and their structures were unambiguously revealed by X-ray diffraction analysis. These nanorings showed highly twisted structures in the solid-state, while exhibiting symmetric 1 H NMR spectra, indicating their conformational flexibilities in solution. The photophysical and electrochemical properties of these nanorings were studied in detail by UV/Vis and fluorescence spectroscopy, femto-second laser-based spectroscopy, and cyclic voltammetry with the aid of DFT calculations. It is shown that hybridization of nanorings with 2,5-thienylene and 2,5-pyrrolylene is an effective means to tune their electronic properties.[a] Dr.

Synthesis of Closed‐Heterohelicenes Interconvertible between Their Monomeric and Dimeric Forms

“…Cyclic pentad 3S2N showed broad absorption and fluorescence bands, reflecting its conformational flexibility as observed in other cyclic hybrids (Figure S6-1). [12][13][14]24] On the other hand, SNSN-S exhibited structured absorption bands at 387 and 412 nm and sharp fluorescence bands with a vibronic structure at 422 and 446 nm. The fluorescence quantum yield is 0.03.…”

Double C–H bond functionalization for C–C coupling at the β-position of thiophenes using palladium-catalyzed 1,4-migration associated with direct arylation

“…So far, the Pd-catalyzed reactions such as Suzuki coupling of heteroarylboronic acids with thiophenes bearing a 2-halobenzene substituent selectively lead to 1,2-diheteroarylated benzene derivatives (Scheme 1a). 8 On the other hand, the C3-heteroarylation of 2-aryl-3-halothiophenes for the access to the corresponding heteroaryl-substituted thiophene derivatives via metal-catalyzed reactions has been rarely described (Scheme 1b). 9,10 This might be due to the tedious multi-step route to many 3-halothiophene derivatives.…”

Suzuki–Miyaura arylation of 2,3‐, 2,4‐, 2,5‐, and 3,4‐dibromothiophenes

“…Arylated thiophene derivatives have been extensively studied as materials and building blocks for optoelectronics, [1][2][3] semiconductors, [4] organic host molecules and sensors, [5,6] porous coordination polymers, and metal-organic frameworks (MOFs). [7,8] Similar S-oxidized thiophenes can be used as diene components in Diels-Alder reactions with various dienophiles to produce sulfoxide-or sulfone-bridged bicyclic systems [9,10] or, when the sulfur bridge is cleaved, the corresponding aromatic derivatives.…”