Synthesis of thermoresponsive polymer gels with crosslinked domains containing iridium complexes for ammonia sensing and N-alkylation catalysis

• Published in: Polymer journal 2023-09, Vol.55 (9), p.945-955
• Main Authors: Furukawa, Shohichi, Okuno, Takahiro, Shimbayashi, Takuya, Takeshita, Hiroki, Fujita, Ken-ichi, Ida, Shohei
• Format: Article
• Language: English
• Subjects: 140/131; 639/301/923/1027; 639/638/455/941; 639/638/77/884; Addition polymerization; Alkylation; Ammonia; Biomaterials; Bioorganic Chemistry; Catalysis; Catalytic activity; Chain transfer; Chemical synthesis; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Crosslinking; Dispersion; Hydrogels; Iridium compounds; Isopropylacrylamide; Monomers; Original Article; Polymer gels; Polymer Sciences; Polymerization; Polymers; Reagents; Structural analysis; Surfaces and Interfaces; Thin Films
• ISSN: 0032-3896; 1349-0540
• DOI: 10.1038/s41428-023-00801-9

Incorporating organometallic complexes into nanodomains in polymer networks would broaden the scopes of gel material design and applicability. In this study, we designed polymer gels containing an iridium complex in the crosslinked domain (CD) of their compartmentalized nanodomain structures and demonstrated their molecular sensing ability and catalytic activity levels. Novel Ir-containing vinyl monomers were first synthesized and then incorporated into a thermoresponsive CD structure by reversible addition–fragmentation chain-transfer polymerization using a hydrophilic bifunctional macro-chain transfer agent with N -isopropylacrylamide and a crosslinker. A model reaction and structural analysis revealed that the product gel exhibited a homogeneously dispersed CD structure containing an Ir complex. The Ir-containing gel immediately changed color by sensing ammonia in a thermoresponsive manner and catalyzed the N -alkylation reaction. Polymer gels containing an iridium complex in their compartmentalized nanodomain structures were designed. Novel Ir-containing vinyl monomers were first synthesized and then incorporated into homogeneously dispersed thermoresponsive nanodomains via living radical polymerization. The product gels exhibited immediate color change by sensing ammonia in a thermoresponsive manner, and catalyzed the N -alkylation reaction. These findings strongly supported the importance of the incorporation of organometallic complexes into the nanodomain of hydrogels for the further development of a novel soft material exhibiting selective molecular recognition abilities and catalytic reactions.