Postfunctionalization of the main chain of Poly(3-hexylthiophene) via anodic C–H phosphonylation

Electrochemical Postfunctionalization of Thiophene–Fluorene Alternating Copolymers via Anodic C–H Phosphonylation

“…The absorption maximum wavelength gradually blue-shifted with an increasing degree of substitution for the samples in both states. According to previous works, 14,26,36 the effective πconjugation length is shortened by the introduction of functional groups onto the thiophene units in the main chain, which results in such a blue shift in the corresponding absorption spectra. DFT calculations for a dimer model also support the blue shift; that is, the introduction of phosphonate into thiophene rings was found to expand the dihedral angle of the adjacent thiophene and fluorene moieties (Figure S12).…”

“…This expectation arises from the attractive optoelectronic properties of CPs, which are derived from their extended πconjugation system throughout the main chains. 11−13 However, with the exception of poly(3-hexylthiophene) (P3HT) 14 and polyaniline derivatives, 15,16 there are few repots in the literature on CPs with phosphonate introduced into the aromatic main chains, indicating that the effects of phosphonate introduced into the aromatic main chains have been unexplored.…”

“…17,18 ePF can be performed when reactants such as nucleophiles are reactive toward the electrochemically doped CPs. 19−26 Recently, anodic phosphonylation at the 4-position in the thiophene rings of P3HT using trialkyl phosphite as a nucleophile was reported 14 (Figure 1a). This approach clearly demonstrates the feasibility of using neutral nucleophiles in the ePF protocol.…”

“…Phosphorus-containing polymers have long been recognized for their versatility in polymer science and their extensive applications across various fields. − Owing to their thermal stability, phosphonate-based polymers have been the desired flame-retardant materials. − Among these polymers, π-conjugated polymers (CPs) containing phosphonate groups or units at the end of side chains (a pendant phosphonate moiety) have been promising materials due to their exceptional applications in chemical sensors, and their unique electronic properties. − Considering these facts, the introduction of phosphonate into aromatic moieties in the main chain is expected to drastically alter their optoelectronic properties. This expectation arises from the attractive optoelectronic properties of CPs, which are derived from their extended π-conjugation system throughout the main chains. − However, with the exception of poly­(3-hexylthiophene) (P3HT) and polyaniline derivatives, , there are few repots in the literature on CPs with phosphonate introduced into the aromatic main chains, indicating that the effects of phosphonate introduced into the aromatic main chains have been unexplored.…”

“…To insert phosphonate groups or units into aromatic moieties in the main chains, electrochemical C–H postfunctionalization ( e PF) of polymer main chains is a promising approach to functionalizing the main chains under mild conditions. , e PF can be performed when reactants such as nucleophiles are reactive toward the electrochemically doped CPs. − Recently, anodic phosphonylation at the 4-position in the thiophene rings of P3HT using trialkyl phosphite as a nucleophile was reported (Figure a). This approach clearly demonstrates the feasibility of using neutral nucleophiles in the e PF protocol.…”