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We report the synthesis of a novel metal–organic capsule constructed from six pyrogallol[4]arene macrocycles, which are switched together by 16 FeIII and 16 CoII ions. This supramolecular structure is the first instance of a spheroidal heterometallic nanocage assembled through a one‐step metal–ligand coordination approach. This new assembly also demonstrates an important proof of concept through the formation of multiple heterometallic metal–metal interactions within the capsule framework. Photophysical and electrochemical studies of self‐assembled capsule films indicate their potential as semiconductors. These materials display unexpected photoelectric conversion properties, thus representing an emergent phenomenon in discrete metal–organic supramolecular assemblies. [ABSTRACT FROM AUTHOR]

Highlights • One AIEE active probe for H 2 S was synthesized. • Both α–cyanostilbenes and maleic anhydride group are the reaction sites. • Supramolecular assembly with β -CD revealed the 3-state mechanism. Abstract One aggregation-induced emission enhancement (AIEE) active compound based on α–cyanostilbenes and maleic anhydride group were synthesized. The "Turn-On" fluorescence recognition for H 2 S was evaluated both in aqueous solution and cells. It was found that cyanostilbenes group acts as the first reactive site and maleimide group acts as the second site to H 2 S. Supramolecular assembly with β -cyclodextrin successfully revealed the reaction mechanism of 3-state model. [ABSTRACT FROM AUTHOR]

Many rhodamine B probes for metal ions and anions showing “orange” fluorescent have attracted a tremendous amount of attention. Herein a rhodamine B-based fluorescent probe 1 showing “green” fluorescence emission in the presence of Hg 2+ was first reported. Self-assembled aggregation was proved to be the crucial factor for the green emitting fluorescence by means of resonance light scattering spectra, fluorescence spectra, ESI mass spectral analysis and SEM image. The probe 1 was developed as a excellent Hg(II)-selective green fluorescence agent in ethanol/HEPES buffer media (v/v = 3:7, pH 7.3) with a detection limit of 0.09 μM. Meanwhile, the green fluorescence of 1 -Hg 2+ can be quenched severely by Cys but not for GSH, S 2− , SO 4 2− , SO 3 2− , CN − , CO 3 2− and HCY. The sequential switching effect for Hg 2+ and then Cys has been achieved in aqueous media and bioimaging with satisfactory results. [ABSTRACT FROM AUTHOR]

Nitric oxide functions as an important signalling molecule in many biological systems. Nanodiamonds (NDs) have attracted enormous attention in the field of biomaterial science for biosensing applications and drug/gene delivery. In this work, one novel Cu(ii)-based rhodamine B probe for NO detection was composed which was covalently bound to the nanodiamond (ND) surface. The results showed that the covalently conjugated ND probe could detect Cu2+ and NO sequentially with high sensitivity, high stability and good reusability compared to a free rhodamine B probe in CH3CN/HEPES (pH 6.8, v/v, 1 : 1). The detection limit for NO was estimated to be 10.5 nM. In addition, the response to NO was reversible in the presence of O3, which has attracted attention in the fields of biology and environmental science. Further analysis of confocal fluorescence microscopy images and the MTT assay indicated that the conjugated ND probe has favorable biocompatibility and low toxicity. This new Cu2+ and NO selective fluorescent ND probe may have potential applications in environmental science and biology. [ABSTRACT FROM AUTHOR]

Cellular uptake of Cr(VI), followed by its reduction to Cr(III) with the formation of kinetically inert Cr(III) complexes, is a complex process. To better understand its physiological and pathological functions, efficient methods for the monitoring of Cr(VI) are desired. In this paper a selective fluorescent probe L , rhodamine hydrazide bearing a benzo[b]furan-2-carboxaldehyde group, was demonstrated as a red chemosensor for Cr(III) at about 586 nm. This probe has been used to probe Cr(III) which is reduced from Cr(VI) by reductants such as glutathione (GSH), vitamin C, cysteine (Cys), H 2 O 2 and Dithiothreitol (DTT) by fluorescence spectra. Cr(VI) metabolism in vivo is primarily driven by Vc and GSH. Vc could reduce CrO 4 2 − to Cr(III) in a faster rate than GSH. The indirectly detection limit for Cr(VI) by L + GSH system was determined to be 0.06 μM at pH = 6.2. Moreover, the confocal microscopy image experiments indicated that Cr(VI) can be reduced to Cr(III) inside cells rapidly and the resulted Cr(III) can be captured and imaged timely by L . [ABSTRACT FROM AUTHOR]

Keywords: coordination cages; heterometallic metal-metal interactions; molecular magnetism; molecule-based semiconductors; photoelectric conversion EN coordination cages heterometallic metal-metal interactions molecular magnetism molecule-based semiconductors photoelectric conversion 1 1 1 04/28/21 20210503 NES 210503 B Metal-Organic Capsules b A mixed Fe SP 3+ sp /Co SP 2+ sp -seamed capsule comprising multiple heterometallic metal-metal interactions is presented by Sisi Feng, Jerry L. Atwood et al. in their Communication on page 10516. Frontispiece: Self-Assembly of a Semiconductive and Photoactive Heterobimetallic Metal-Organic Capsule Coordination cages, heterometallic metal-metal interactions, molecular magnetism, molecule-based semiconductors, photoelectric conversion. [Extracted from the article]

Complexes [Cr(III)(SA)(en) 2 ] + ( 1 ), [Cr(III)(SA)(DETA)(H 2 O)] + ( 2 ) and [Cr(III)(SA)(TETA)] + ( 3 ) were synthesized (H 2 SA = salicylic acid, en = ethylenediamine, DETA = diethylenetriamine, TETA = triethylenetetramine). Kinetics studies show that 2 is the most instable one among these complexes. In addition, only 2 is found to be a very efficient catalyst of the cleavage of PBR322 DNA in the absence of any added cofactor. The degradation rate from supercoiled form to nicked form was 1.05 ± 0.081 h − 1 (10 − 5 M) at pH 7.4 and 37 °C. Thiobarbituric acid-reactive substances assay shows 2 fail to produce OH causing any degradation of deoxyribose ring even in the presence of ascorbic acid. Ethidium bromide displacement assay suggests that only 2 can kick out EB from the groove of DNA. The interaction with DNA causes a blue shift of the d → d transition spectra of 2 . [ABSTRACT FROM AUTHOR]