Acylthioureas as anion transporters: the effect of intramolecular hydrogen bonding

Small molecule synthetic anion transporters may have potential application as therapeutic agents for the treatment of diseases including cystic fibrosis and cancer. Understanding the factors that can dictate the anion transport activity of such transporters is a crucial step towards their application in biological systems. In this study a series of acylthiourea anion transporters were synthesised and their anion binding and transport properties in POPC bilayers have been investigated. The transport activity of these receptors is dominated by their lipophilicity, which is in turn dependent on both substituent effects and the formation and strength of an intramolecular hydrogen bond as inferred from DFT calculations. This is in contrast to simpler thiourea systems, in which the lipophilicity depends predominantly on substituent effects alone

Lipophilic balance – a new design principle for transmembrane anion carriers

Despite extensive interest in transmembrane anion carriers (anionophores), the factors that govern activity are still only partly understood. Herein we report a study which identifies a new principle for anionophore design, that of “lipophilic balance”. A series of simple thioureas with identical molecular formulae has been prepared and assayed for chloride/nitrate transport activity in synthetic vesicles. The molecules differ only in the positioning of the phenylthiourea binding unit within an 11-carbon linear chain. They are shown to possess very similar lipophilicities and anion affinities, while a test for leaching establishes that they locate almost exclusively in the vesicle membranes. Notwithstanding their close similarities, activities across the series show >5-fold variation, peaking when the phenylthiourea group is centrally located. The results suggest that transport is favoured by a balanced array of lipophilic substituents, possibly because this arrangement facilitates transfer of the complexed anion into the apolar membrane interio

A giant M2L3 metallo-organic helicate based on phthalocyanines as a host for electroactive molecules

An unprecedented Fe2Pc3 metallo-organic helicate has been assembled using a bidentate phthalocyanine (Pc) ligand, 2-formylpyridine and Fe(OTf)2. This giant helicate has proved itself as a host for large redox-active guests such as fullerene and naphthalenediimide derivatives. Photoactivated electronic interactions between components occur in the host-guest complexFinancial support from Comunidad de Madrid, Spain (S2013/MIT-2841, FOTOCARBON), and MINECO, Spain (CTQ2017-85393-P), and the UK EPSRC (EP/M008258/2) is acknowledge

Anion binding and transport properties of cyclic 2,6-bis(1,2,3-triazol-1-yl)pyridines

A series of cyclic 2,6-bis-(1,2,3-triazolyl)-pyridine anion receptors with thiourea functionalities were synthesized by click reaction of 2,6-diazidopyridine with protected propargylamine followed by condensation of a bisthiocyanate derivative with a series of diamines. Their chloride binding affinities as well as their transport properties in POPC bilayers were examined. These receptors were found to function as anion carriers, which can mediate both Cl?/NO3? antiport and H+/Cl? symport, and the transport activity of these hosts were dominated by their lipophilicity