Donor–Acceptor Conjugated Copolymers Containing Transition-Metal Complex: Intrachain Magnetic Exchange Interactions and Magneto-Optical Activity

Abstract

A donor−acceptor conjugated copolymer containing thienothiophene (donor) units and Co(II) complexes (acceptor) has been synthesized and characterized. The studies of magnetic properties of the polymers by SQUID and EPR measurements showed antiferromagnetic exchange interaction between neighboring spin centers along with the polymer backbone through intrachain interactions. It is the first time that the D−A conjugated polymer backbone serves as bridging ligands for magnetic couplings, making these type of polymers promising as magnetic materials. Moreover, the magneto-optical activity of polymer LCP1 was characterized using magnetic circular dichroism spectroscopy. It was found that the material exhibits a large magneto-optic rotation with a peak Verdet constant of 2980 deg•T −1 •m −1 at 590 nm.

Synthesis, characterization, and semiconducting properties of π-conjugated polymers containing hydrogen-bonded bis-pyridine-thieno[3,2-b]thiophene moieties

“…[16][17][18][19][20][21][22] (3) The pyridine nitrogen atom with an unshared electron pair, like tertiary amines, can be metal ion coordinated, N-protonated, N-oxidated, and quaternized. [23][24][25][26][27][28] When a pyridine reacts as a base or a nucleophile, it forms a pyridinium cation in which the aromatic sextet is retained and the nitrogen acquires a formal positive charge. These reactions at nitrogen can significantly alter the optical and electrical properties of the polymers.…”

“…These reactions at nitrogen can significantly alter the optical and electrical properties of the polymers. 23,24,29,30 Despite these advantages, the pyridines as building blocks of high-performance semiconducting polymers have been restricted to a few examples so far, especially, focusing on the pyridine-flanked diketopyrrolopyrrole (PyDPP) type polymers. 10,12,[31][32][33][34][35] Polymers with high charge carrier mobility in organic electronic devices usually have planar structures and extended p-electron delocalization.…”