ABSTRACT
Halogen-bonding (XB) interactions were exploited in the solution-phase assembly of anion-templated pseudorotaxanes between an isophthalamide-containing macrocycle and bromo- or iodo-functionalised pyridinium threading components. (1)Hâ NMR spectroscopic titration investigations demonstrated that such XB interpenetrated assemblies are more stable than analogous hydrogen bonding (HB) pseudorotaxanes. The stability of the anion-templated halogen-bonded pseudorotaxane architectures was exploited in the preparation of new halogen-bonding interlocked catenane species through a Grubbs' ring-closing metathesis (RCM) clipping methodology. The catenanes' anion recognition properties in the competitive CDCl(3)/CD(3) OD 1:1 solvent mixture revealed selectivity for the heavier halides iodide and bromide over chloride and acetate.
Subject(s)
Catenanes/chemistry , Anions/chemistry , Catenanes/chemical synthesis , Halogens/chemistry , Hydrogen Bonding , Magnetic Resonance Spectroscopy , Rotaxanes/chemical synthesis , Rotaxanes/chemistryABSTRACT
Iodotriazole and triazole anion recognition groups have been integrated into a picket-fence zinc(ii)-metalloporphyrin scaffold to produce receptors for anion recognition and sensing applications. (1)H NMR and UV/visible spectroscopic investigations reveal both host systems exhibit strong anion binding affinities in a range of solvent media. Importantly, the halogen-bonding iodotriazole-containing porphyrin-based host displays halide binding affinities substantially larger than the protic-functionalised analogue concomitant with a reduced strength of oxoanion complexation.
Subject(s)
Halogens/chemistry , Porphyrins/chemistry , Triazoles/chemistry , Crystallography, X-Ray , Hydrogen Bonding , Models, Molecular , Molecular Conformation , Solvents/chemistryABSTRACT
Triazole and triazolium groups have been integrated into a zinc(II) metalloporphyrin-based structural framework to produce two porphyrin-cages for anion sensing applications. UV/visible spectroscopic titration investigations reveal both host systems exhibit strong anion binding affinities, with the positively-charged triazolium-porphyrin cage capable of colorimetric sensing halides, fluoride and chloride, and oxoanions in acetone-water solvent mixtures.
Subject(s)
Chemistry Techniques, Analytical/instrumentation , Metalloporphyrins/chemistry , Optical Phenomena , Triazoles/chemistry , Anions/analysis , Anions/chemistry , Hydrogen Bonding , Lewis Acids , Models, Molecular , Molecular Conformation , Water/chemistry , Zinc/chemistryABSTRACT
A novel anion templation route has been developed to synthesise two new catenanes, which are observed to selectively complex chloride in protic solvent media.
ABSTRACT
A new, versatile chloride-anion-templating synthetic pathway is exploited for the preparation of a series of eight new [2]rotaxane host molecules, including the first sulfonamide interlocked system. (1)H NMR spectroscopic titration investigations demonstrate the rotaxanes' capability to selectively recognise the chloride anion in competitive aqueous solvent media. The interlocked host's halide binding affinity can be further enhanced and tuned through the attachment of electron-withdrawing substituents and by increasing its positive charge. A dicationic rotaxane selectively binds chloride in 35% water, wherein no evidence of oxoanion binding is observed. NMR spectroscopy, X-ray structural analysis and computational molecular dynamics simulations are used to account for rotaxane formation yields, anion binding strengths and selectivity trends.
