两亲性均聚物作为水中的反应介质：聚合物纳米囊内的产物选择性

Amphiphilic homopolymer as a reaction medium in water: product selectivity within polymeric nanopockets.

作者信息

Arumugam Selvanathan, Vutukuri Dharma Rao, Thayumanavan S, Ramamurthy V

机构信息

Department of Chemistry, University of Miami, Coral Gables, Florida 33124, USA.

出版信息

J Am Chem Soc. 2005 Sep 28;127(38):13200-6. doi: 10.1021/ja051107v.

DOI:10.1021/ja051107v

PMID:16173747

Abstract

A styrene-based water-soluble polymer has been explored for its use as a host for lipophilic substrates in aqueous medium. Unimolecular reactions, namely, photo-Fries rearrangement of naphthyl esters, alpha-cleavage reaction of 1-phenyl-3-p-tolyl-propan-2-one, and Norrish type I and type II reactions of benzoin alkyl ethers were examined. We find that the hydrophobic domains generated by the polymer not only restrict the mobility of the radicals but also modestly incarcerate the substrate, intermediates, and products during the time scale of the reactions. Comparative studies of the same photoreactions in micelles formed from small molecule surfactants and an amphiphilic diblock copolymer demonstrate that the styrene-based water-soluble polymer aggregates in aqueous medium offer better selectivity.

摘要

一种基于苯乙烯的水溶性聚合物已被研究用于在水性介质中作为亲脂性底物的主体。研究了单分子反应，即萘酯的光弗里斯重排、1-苯基-3-对甲苯基-丙-2-酮的α-裂解反应以及安息香烷基醚的I型和II型诺里什反应。我们发现，聚合物产生的疏水区域不仅限制了自由基的迁移率，而且在反应时间尺度内适度地包封了底物、中间体和产物。对由小分子表面活性剂和两亲性二嵌段共聚物形成的胶束中相同光反应的比较研究表明，水性介质中基于苯乙烯的水溶性聚合物聚集体具有更好的选择性。