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Supramolecular chemistry is a central topic in modern chemistry. It touches on many traditional disciplines, such as organic chemistry, inorganic chemistry, physical chemistry, materials chemistry, environmental chemistry, and biological chemistry. Supramolecular hosts, inter alia macrocyclic hosts, play critical roles in supramolecular chemistry. Calix[4]pyrroles, non-aromatic tetrapyrrolic macrocycles defined by sp3 hybridized meso bridges, have proved to be versatile receptors for neutral species, anions, and cations, as well as ion pairs. Compared to the parent system, octamethylcalix[4]pyrrole and its derivatives bearing simple appended functionalities, strapped calix[4]pyrroles typically display enhanced binding affinities and selectivities. In this review, we summarize advances in the design and synthesis of strapped calix[4]pyrroles, as well as their broad utility in molecular recognition, supramolecular extraction, separation technology, ion transport, and as agents capable of inhibiting cancer cell proliferation. Future challenges within this sub-field are also discussed. [ABSTRACT FROM AUTHOR]

Polybenzimidazole (PBI) membranes with nanophase-separated structure induced by non-ionic hydrophilic side chain are designed and fabricated for vanadium flow batteries (VFBs). The designed PBI membranes are prepared by grafting non-ionic hydrophilic side chains via an N-substitution reaction. This molecular modification induces nanophase separation and formation of hydrophilic clusters, which act as effective proton transfer pathways, hence dramatically improving the proton conductivity. Meanwhile, the vanadium permeability is inappreciable due to the appropriate size of hydrophilic clusters and Donnan exclusion of protonated grafted-PBI membranes (GPBI). Free from ion exchange groups, GPBI membranes maintain the good chemical stability of the pristine PBI membrane. As a result, the designed membrane exhibits an impressive performance, combining ultrahigh proton conductivity, ion selectivity and chemical stability. The GPBI-based VFB exhibits a coulombic efficiency of over 99% and an energy efficiency of 84% at 120 mA cm−2, the highest reported for dense PBI membranes for VFB applications. The decent stability of GPBI membranes is demonstrated by the stable performance over 200 charge–discharge cycles and the ex situ immersion test. This work provides a new insight into the design of high-performance PBI membranes for VFB applications. [ABSTRACT FROM AUTHOR]

A novel integrally thin skinned asymmetric anion exchange membrane (ISAAEM) with sufficiently low ion exchange capacity (IEC) was proposed to improve the chemical stability of AEMs for vanadium flow batteries (VFBs). The ISAAEM with an IEC of 0.72 meq. g−1 showed low area resistance, slight VO2+ crossover and good electrochemical performance in VFBs. [ABSTRACT FROM AUTHOR]

Mercury is a highly toxic heavy metal and it poses a serious threat to the natural environment and human health. Thus, selective detection of trace mercury ( e.g. inorganic mercury and methylmercury) in the environment is critical yet challenging. Herein, we describe the rational design and facile synthesis of a new triphenylamine-based phenylboronic acid fluorescent probe (TPA-PBA) for selective detection of Hg 2+ and CH 3 Hg + . Due to the inherent specificity of the displacement reaction between phenylboronic acid and mercury, this probe exhibits exceptionally high selectivity towards Hg 2+ /CH 3 Hg + against other tested ions with ppb-level sensitivity. More importantly, the probe TPA-PBA is effective and selective in detecting Hg 2+ /CH 3 Hg + in tap water and real-world groundwater, indicating its potential practical applications in in situ and online mercury detection in real-world scenarios. With TPA-PBA based test strips Hg 2+ can be distinguished from CH 3 Hg + by the naked eye. This study could accelerate the development of low-cost, highly efficient and selective fluorescent probes for rapid trace mercury detection.

Crystalline supramolecular architectures mediated by cations, anions, ion pairs or neutral guest species are well established. However, the robust crystallization of a well-designed receptor mediated by labile anionic solvate clusters remains unexplored. Herein, we describe the synthesis and crystalline behaviors of a trimacrocyclic hexasubstituted benzene 2 in the presence of guanidium halide salts and chloroform. Halide hexasolvate clusters, viz. [Cl(CHCl 3 ) 6 ] - , [Br(CHCl 3 ) 6 ] - , and [I(CHCl 3 ) 6 ] - , were found to be critical to the crystallization process, as suggested by the single-crystal structures, X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and NMR spectroscopy. This study demonstrates the hitherto unexpected role that labile ionic solvate clusters can play in stabilizing supramolecular architectures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)