Wang Lina, Malpass-Evans Richard, Carta Mariolino, McKeown Neil B, Reeksting Shaun B, Marken Frank
Department of Chemistry, University of Bath Claverton Down Bath BA2 7AY UK
EaStCHEM, School of Chemistry, University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh Scotland EH9 3JF UK.
RSC Adv. 2021 Aug 12;11(44):27432-27442. doi: 10.1039/d1ra04543a. eCollection 2021 Aug 9.
Microporous polymer materials based on molecularly "stiff" structures provide intrinsic microporosity, typical micropore sizes of 0.5 nm to 1.5 nm, and the ability to bind guest species. The polyamine PIM-EA-TB contains abundant tertiary amine sites to interact hydrogen bonding to guest species in micropores. Here, quercetin and catechin are demonstrated to bind and accumulate into PIM-EA-TB. Voltammetric data suggest apparent Langmuirian binding constants for catechin of 550 (±50) × 10 M in acidic solution at pH 2 (PIM-EA-TB is protonated) and 130 (±13) × 10 M in neutral solution at pH 6 (PIM-EA-TB is not protonated). The binding capacity is typically 1 : 1 (guest : host polymer repeat unit), but higher loadings are readily achieved by host/guest co-deposition from tetrahydrofuran solution. In the rigid polymer environment, bound -quinol guest species exhibit 2-electron 2-proton redox transformation to the corresponding quinones, but only in a thin mono-layer film close to the electrode surface. Release of guest molecules occurs depending on the level of loading and on the type of guest either spontaneously or with electrochemical stimuli.
基于分子“刚性”结构的微孔聚合物材料具有固有微孔性、典型微孔尺寸为0.5纳米至1.5纳米以及结合客体物种的能力。聚胺PIM-EA-TB含有丰富的叔胺位点，可通过氢键与微孔中的客体物种相互作用。在此，已证明槲皮素和儿茶素可结合并积聚到PIM-EA-TB中。伏安数据表明，在pH值为2的酸性溶液中（PIM-EA-TB被质子化），儿茶素的表观朗缪尔结合常数为550（±50）×10⁶ M，在pH值为6的中性溶液中（PIM-EA-TB未被质子化）为130（±13）×10⁶ M。结合容量通常为1∶1（客体∶主体聚合物重复单元），但通过从四氢呋喃溶液中共沉积主体/客体可轻松实现更高的负载量。在刚性聚合物环境中，结合的对苯二酚客体物种会发生2电子2质子氧化还原转化为相应的醌，但仅在靠近电极表面的单层薄膜中发生。客体分子的释放取决于负载水平和客体类型，可自发发生或通过电化学刺激发生。
