ResearchPad - host–guest-systems https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Luminescent Anion Sensing by Transition‐Metal Dipyridylbenzene Complexes Incorporated into Acyclic, Macrocyclic and Interlocked Hosts]]> https://www.researchpad.co/article/elastic_article_6898 A series of acyclic, macrocyclic and mechanically interlocked luminescent anion sensors have been prepared by incorporation of the isophthalamide motif into dipyridylbenzene to obtain cyclometallated complexes of PtII and RuII. Anion titrations with the ruthenium [2]rotaxane demonstrate a marked increase in chloride binding affinity and indicate the interlocked receptor is capable of chloride recognition even in competitive 30 % aqueous mixtures (see figure).

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<![CDATA[Photo‐responsive Bioactive Surfaces Based on Cucurbit[8]uril‐Mediated Host–Guest Interactions of Arylazopyrazoles]]> https://www.researchpad.co/article/5b4b2d7e463d7e744f1f4961

Abstract

A photoswitchable arylazopyrazole (AAP) derivative binds with cucurbit[8]uril (CB[8]) and methylviologen (MV2+) to form a 1:1:1 heteroternary host–guest complex with a binding constant of K a=2×103m −1. The excellent photoswitching properties of AAP are preserved in the inclusion complex. Irradiation with light of a wavelength of 365 and 520 nm leads to quantitative E‐ to Z‐ isomerization and vice versa, respectively. Formation of the Z‐isomer leads to dissociation of the complex as evidenced using 1H NMR spectroscopy. AAP derivatives are then used to immobilize bioactive molecules and photorelease them on demand. When Arg‐Gly‐Asp‐AAP (AAP–RGD) peptides are attached to surface bound CB[8]/MV2+ complexes, cells adhere and can be released upon irradiation. The heteroternary host–guest system offers highly reversible binding properties due to efficient photoswitching and these properties are attractive for designing smart surfaces.

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