The copolymerization of olefins with carbon monoxide (CO) affords aliphatic polyketones, which exhibit excellent mechanical strength, crystallinity, photodegradability, hydrophilicity, and surface and barrier properties. The chain-transfer copolymerization of ethylene with CO has offered an available method to regulate the molecular weight of polyketones that are amenable to conventional injection molding and extrusion. In this study, we investigated the copolymerization pathway using the [P,O]-Pd catalyst in a protonic environment. The key chain-propagating species are identified by state-of-the-art electrospray ionization mass spectrometry. These findings indicate that the copolymerization can be performed in different protonic solvents in a chain-transfer fashion; thus, the molecular weight of polyketone products can be regulated over the range of 8.13–238 kg/mol. In particular, such a chain-transfer method renders the formation of novel telechelic structures having a ketone backbone and diester chain ends selectively. The differences between [P,O]-Pd and diphosphine–Pd catalysts have been disclosed, and this study provides insights into the discovery and design of novel catalysts for this interesting copolymerization reaction.

中文翻译：

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阳离子 [P,O]-Pd 催化乙烯与一氧化碳链转移共聚的机理见解

烯烃与一氧化碳 (CO) 的共聚得到脂肪族聚酮，具有优异的机械强度、结晶度、光降解性、亲水性以及表面和阻隔性能。乙烯与CO的链转移共聚提供了一种调节聚酮分子量的可用方法，该聚酮适合传统的注塑和挤出。在这项研究中，我们研究了在质子环境中使用[P,O]-Pd催化剂的共聚途径。通过最先进的电喷雾电离质谱法鉴定关键链传播物质。这些发现表明共聚可以在不同的质子溶剂中以链转移方式进行；因此，聚酮产品的分子量可以在8.13-238 kg/mol范围内调节。特别地，这种链转移方法使得选择性地形成具有酮主链和二酯链末端的新型遥爪结构。 [P,O]-Pd 和二膦-Pd 催化剂之间的差异已经被揭示，这项研究为这种有趣的共聚反应的新型催化剂的发现和设计提供了见解。