A family of novel halogen bonding (XB) and hydrogen bonding (HB) heteroditopic [2]rotaxane host systems constructed by active metal template (AMT) methodology, were studied for their ability to cooperatively recognise lithium halide (LiX) ion-pairs. 1 H NMR ion-pair titration experiments in CD 3 CN:CDCl 3 solvent mixtures revealed a notable "switch-on" of halide anion binding in the presence of a cobound lithium cation, with rotaxane hosts demonstrating selectivity for LiBr over LiI. The strength of halide binding was shown to greatly increase with increasing number of halogen bond donors integrated into the interlocked cavity, where an all-XB rotaxane was found to be the most potent host for LiBr. DFT calculations corroborated these findings, determining the mode of LiX ion-pair binding. Notably, ion-pair binding was not observed with the corresponding XB/HB macrocycles alone, highlighting the cooperative, heteroditopic, rotaxane axle-macrocycle component mechanical bond effect as an efficient strategy for ion-pair recognition in general.

Residue steroidal estrogens in environmental and food samples have become a cause for concern as they can affect organisms at low ppt concentrations. Analytical method development plays a key role in trace estrogen analysis due to the combination of low concentrations and complicated sample matrices. Reliable quantification of these trace level steroidal estrogens has become a major concern during the past decade. This mini review focuses on advancements in analytical methods developed for estrogen detection and quantification in environmental and food samples from 2014 -2016. A comprehensive overview of the novelties and the advantages of the recently developed sample pre-concentration, clean-up, and detection methods are discussed. During the past three years, a wide variety of sample extraction methods including, the utilization of innovative imprinted magnetic sorbents, QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and various microextraction methods such as Dispersive liquid-liquid micro extraction (DLLME), Thin film micro extraction (TFME), Solid phase microextraction (SPME), and Vortex assisted hollow fiber liquid-phase micro extraction (VA-HF-LPME) have been

A family of novel halogen bonding (XB) and hydrogen bonding (HB) heteroditopic [2]rotaxane host systems constructed by active metal template (AMT) methodology, were studied for their ability to cooperatively recognise lithium halide (LiX) ion-pairs. 1H NMR ion-pair titration experiments in CD3CN:CDCl3 solvent mixtures revealed a notable “switch-on“ of halide anion binding in the presence of a co-bound lithium cation, with rotaxane hosts demonstrating selectivity for LiBr over LiI. The strength of halide binding was shown to greatly increase with increasing number of halogen bond donors integrated into the interlocked cavity, where an all-XB rotaxane was found to be the most potent host for LiBr. DFT calculations corroborated these findings, determining the mode of LiX ion-pair binding. Notably, ion-pair binding was not observed with the corresponding XB/HB macrocycles alone, highlighting the cooperative heteroditopic rotaxane axle-macrocycle component mechanical bond effect as an efficient strategy for ion-pair recognition in general.