abstract
The synthesis and anion-recognition properties of the first halogen-bonding rotaxane host to sense anions in water is described. The rotaxane features a halogen-bonding axle component, which is stoppered with water-solubilizing permethylated beta-cyclodextrin motifs, and a luminescent tris(bipyridine) ruthenium (II)-based macrocycle component. H-1 NMR anion-binding titrations in D2O reveal the halogen-bonding rotaxane to bind iodide with high affinity and with selectively over the smaller halide anions and sulfate. The binding affinity trend was explained through molecular dynamics simulations and free-energy calculations. Photo-physical investigations demonstrate the ability of the interlocked halogen-bonding host to sense iodide in water, through enhancement of the macrocycle component's Ru-II metal-ligand charge transfer (MLCT) emission.
keywords
ANION RECOGNITION; AQUEOUS-MEDIA; SUPRAMOLECULAR CHEMISTRY; TRANSITION-METAL; HIGH-AFFINITY; HOST SYSTEM; RECEPTOR; FLUORESCENT; BINDING; CHLORIDE
subject category
Chemistry
authors
Langton, MJ; Marques, I; Robinson, SW; Felix, V; Beer, PD
our authors
Igor Oliveira Marques
Junior Researcher
Vítor Félix
Associate Professor with Aggregationacknowledgements
M.J.L. thanks the EPSRC for a Doctoral Award and the European Research Council for funding under the European Union's Framework Program (FP7/2007-2013) ERC Advanced Grant Agreement no. 267426. I.M. thanks the FCT for the PhD scholarship SFRH/BD/87520/2012. S.W.R. thanks the Clarendon Fund and St. John's College, Oxford for financial support. The theoretical studies were supported by FEDER through COMPETE and FCT under project UID/BIM/04501/2013.