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A green strategy was developed for recycling a thermosetting unsaturated polyester resin (TUPR) using phosphotungstic acid hydrate (HPWH) coupled with acetic acid under mild conditions. As an environmentally benign catalyst, HPWH greatly enhanced the swelling of TUPR in acetic acid and exhibited high catalytic activity for the selective catalytic degradation of TUPR. Acetic acid improved HPW–TUPR interfacial contact, which facilitated the HPW diffusion and transmission in the TUPR internal matrix. The obtained functional products can be controlled by adjusting the reaction condition and easily separated from the reaction system. [ABSTRACT FROM AUTHOR]

While controlling the wheel shuttling of prototype [2]rotaxanes has been readily achieved, which promotes the development of intelligent supramolecular systems and materials, it remains a grand challenge to access higher ordered rotaxane systems with precisely controllable relative motion between component parts. Herein, a unique tristable [3]rotaxane was synthesized by threading two cyclobis(paraquat-p-phenylene) (CBPQT4+) macrocycles with a dumbbell component, which contained three recognition sites, including a photoactive azobenzene (AB) unit and a redox active tetrathiofulvalene (TTF) unit separated by a dioxynaphthalene (DNP) unit. Upon UV (365 nm)/yellow (> 525 nm) light irradiation, the Z/E photoisomerization of the AB unit could be triggered to drive the CBPQT4+ wheel (A) to shuttle between the AB and DNP units, with the CBPQT4+ wheel (B) maintained on the TTF unit. Furthermore, regulating the redox states of the TTF unit without light irradiation can induce the CBPQT4+ wheel (B) to shuttle between the TTF and DNP units. The construction of this unique orthogonal photo and redox stimuli-responsive [3]rotaxane is conducive to the development of higher ordered rotaxane-based molecular systems with controllable sophisticated properties and functions. [ABSTRACT FROM AUTHOR]

Herein, we report a 54-nuclei copper nanocluster, [Cu54S13O6(tBuS)20(tBuSO3)12] (Cu54), which is the largest atom-precise CuI/CuII mix-valent cluster reported. The Cu54 nanoclusters supported by TiO2 exhibit decent photocatalytic activity for phenol degradation under visible light. This work provides a platform to explore the catalytic behaviors of CuI/CuII nanosystems. [ABSTRACT FROM AUTHOR]

The development of “turn-on” fluorescence probes for biological thiol detection has received great attention in recent years because abnormal levels of these mercapto biomolecules are always related to some form of disease. In this work, a series of AIE-active polymer probes for biothiol detection were designed and synthesized, comprising disulfide-functionalized hyperbranched poly(amido amine) (ssHPA) as the hydrophilic matrix, tetraphenylethene (TPE) as the hydrophobic AIE-active fluorogen and a disulfide bond as the cleavable functional linkage, defined as TPE-ssHPAs. When these polymers were targeted as “turn on” fluorescence probes for the detection of biothiols, no organic solvents or heavy metal ions were needed as the quencher to eliminate background signals because of the relatively rigid dendritic structure. Upon introducing glutathione or cysteine to an aqueous solution of TPE-ssHPAs, bright fluorescence occurred because of the collapsing of the dendritic structure, leading to the aggregation of TPE units. Further in vitro experiments verified that TPE-ssHPAs is a qualified probe for biothiol detection in living cells. In addition, this strategy of embedding AIEgens inside a relatively rigid hyperbranched polymer offers an effective solution to “pre-quench” the fluorescence of “turn-on” type AIE-active sensors. [ABSTRACT FROM AUTHOR]

The selective removal of oxygen from 5-hydroxymethylfurfural (HMF) is challenging for the effective utilization of biomass. The catalytic mechanisms of palladium acetate toward the conversion of HMF to furfuryl alcohol (FFA), 5-methylfurfural (5-MF) and 2,5-dihydroxymethyl furan (DHMF) have been theoretically investigated. The decarbonylation of HMF to FFA includes (i) migratory extrusion, (ii) metal-acetate-co-assisted deprotonation, (iii) decarbonylation, (iv) metal-assisted deprotonation, and (v) migratory extrusion and catalyst regeneration. Both hydrogenation and deoxidation of HMF with HCOOH as the H-source involve (i) migratory extrusion, (ii) oxidative addition, (iii) reductive elimination, (iv) metal-assisted deprotonation, and (v) migratory extrusion and catalyst regeneration. The C–H bond cleavage is the crucial reaction step, in which the metal-acetate-co-assisted deprotonation is kinetically more preferable than the oxidative addition. Both FFA and DHMF are kinetically superior to 5-MF. In terms of selectivity, increasing the temperature is beneficial to decarbonylation and decreasing the temperature is advantageous to hydrogenation. The present finding provides molecular-level insight into the functions of both the metal-center and coordinated-ligand in the Pd(OAc)2 catalyst, which may drive the novel design of catalytic systems toward both decarbonylation and hydrogenation reactions. [ABSTRACT FROM AUTHOR]

Photochromic [2]rotaxanes with bidirectional photoswitchability were fabricated, whose colored states exhibit remarkable visible-light and thermal stabilities as revealed by systematically spectroscopic investigations. [ABSTRACT FROM AUTHOR]

We report herein the identification of an immunomodulatory metal-based complex 1 as a direct inhibitor of TLR1/2 heterodimerization. Both enantiomers of complex 1 selectively suppressed TNF-α and TLR1/2 heterodimerization in Pam3CSK4-induced macrophages, with Λ-1 being more potent than Δ-1. Moreover, the complexes inhibited NF-κB transduction via the modulation of TLR1/2 signaling. To our knowledge, complex 1 is the first metal-based inhibitor of TLR1/2 heterodimerization reported to date. [ABSTRACT FROM AUTHOR]

A long lifetime iridium(iii) complex chemosensor 1 for cysteine detection has been synthesized. The luminescence signal of 1 could be recognized in strongly fluorescent media through time-resolved emission spectroscopy (TRES). The detection of cysteine in a living zebrafish was demonstrated. [ABSTRACT FROM AUTHOR]

A novel luminescent cyclometalated iridium(iii) complex 1 was synthesized and employed as a chemosensor for the detection of Al3+ ions. Compared with common organic chemosensors, 1 displays a larger Stokes shift and a long lifetime luminescence that allow 1 to detect Al3+ ions in fluorescent dye spiked strong fluorescence media and potentially be used in strongly autofluorescent biological samples. [ABSTRACT FROM AUTHOR]

We report herein the identification of an immunomodulatory natural product-like compound 1 as a direct inhibitor of TLR1–TLR2 heterodimerization. Compound 1 suppressed TNF-α and IL-6 secretion in Pam3CSK4-induced macrophages. Moreover, compound 1 inhibited the phagocytic activity of macrophages, presumably through modulation of TLR1–TLR2 signaling and inactivation of NF-κB. Molecular docking revealed that compound 1 bound to the interface region of TLR1–TLR2 by forming two hydrogen bonds with residues lining the binding site. To our knowledge, compound 1 has been only the second inhibitor overall of TLR1–TLR2 heterodimerization reported to date. [ABSTRACT FROM AUTHOR]

We report herein the synthesis of a series of cyclometallated iridium(iii) complexes as luminescent G-quadruplex-selective probes, which were used to construct AND, OR and INHIBIT logic gates for the detection of HgII and AgI ions. To our knowledge, this is the first time that the C–AgI–T mismatched base pair has been used for the construction of luminescent assays or logic gates. [ABSTRACT FROM AUTHOR]

An iridium(iii) complex exhibiting higher responce towards i-motif DNA over dsDNA and ssDNA was employed for the construction of a TdT activity detection platform. The assay exhibited a linear signal enhancement for TdT in the concentration range of 0 to 8 U mL−1, and the limit of detection for TdT was 0.25 U mL−1. [ABSTRACT FROM AUTHOR]

We report herein a novel iridium(iii) complex 1 as an antitumour necrosis factor agent and the first metal-based inhibitor of TACE enzymatic activity. Complex 1 inhibited TNF-α secretion and p38 phosphorylation in human monocytic THP-1 cells. [ABSTRACT FROM AUTHOR]

Correction for ‘Inhibition of TLR1/2 dimerization by enantiomers of metal complexes’ by Li-Juan Liu et al., Chem. Commun., 2016, 52, 12278–12281. [ABSTRACT FROM AUTHOR]

Herein, we report a 54-nuclei copper nanocluster, [Cu 54 S 13 O 6 ( t BuS) 20 ( t BuSO 3 ) 12 ] (Cu 54 ), which is the largest atom-precise Cu I /Cu II mix-valent cluster reported. The Cu 54 nanoclusters supported by TiO 2 exhibit decent photocatalytic activity for phenol degradation under visible light. This work provides a platform to explore the catalytic behaviors of Cu I /Cu II nanosystems.

Developing new photoswitchable noncovalent interaction motifs with controllable bonding affinity is crucial for the construction of photoresponsive supramolecular systems and materials. Here we describe a unique "photolocking" strategy for realizing photoswitchable control of quadruple hydrogen-bonding interactions on the basis of modifying the ureidopyrimidinone (UPy) module with an ortho -ester substituted azobenzene unit as the "photo-lock". Upon light irradiation, the obtained Azo-UPy motif is capable of unlocking/locking the partial H-bonding sites of the UPy unit, leading to photoswitching between homo- and heteroquadruple hydrogen-bonded dimers, which has been further applied for the fabrication of novel tunable hydrogen bonded supramolecular systems. This "photolocking" strategy appears to be broadly applicable in the rational design and construction of other H-bonding motifs with sufficiently photoswitchable noncovalent interactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The fundamental understanding of the cooperativity of a Brønsted acid together with its anion for cellulose conversion in an aqueous solution is limited at present, in which cellobiose has usually been regarded as a bridge that connects monosaccharides and cellulose. The mechanism of β-cellobiose conversion to 5-hydroxymethylfurfural (HMF) catalyzed by a Brønsted acid (H 3 O + ) accompanied by counteranions in an aqueous solution has been studied using quantum chemical calculations at the M06-2X/6-311++G(d,p) level under a polarized continuum model (PCM-SMD). For the formation of the first HMF from cellobiose, there are three reaction pathways, i.e., through cellobiulose and glycosyl-HMF (C/H), through cellobiulose and fructose (C/F/H), and through glucose (C/G/H). For these three reaction pathways, the rate-determining steps are associated with the intramolecular [1,2]-H shift in the aldose-ketose tautomerization. C/H is the thermodynamically predominant pathway, while C/G/H is the kinetically dominant pathway. From cellobiose, the origin of the first HMF results kinetically from a small proportion of both C/H and C/F/H and from a large proportion of C/G/H. For the role of the counteranion in the catalytic activity of H 3 O + , the halide anions (Cl - and Br - ) act as promoters, whereas both NO 3 - anions and carboxylate-containing anions behave as inhibitors. The roles of these anions in β-cellobiose conversion to HMF can be correlated with their electrostatic potential and atomic number, which may cause a decrease in the relative enthalpy energy and the value of entropy on interacting with the cation moiety. These insights may advance the novel design of sustainable conversion systems for cellulose conversion into HMF.

A novel luminescent cyclometalated iridium(III) complex was synthesized and employed as a chemosensor for the detection of Al(3+) ions. Compared with common organic chemosensors, displays a larger Stokes shift and a long lifetime luminescence that allow to detect Al(3+) ions in fluorescent dye spiked strong fluorescence media and potentially be used in strongly autofluorescent biological samples.

We report herein the synthesis of a series of cyclometallated iridium(iii) complexes as luminescent G-quadruplex-selective probes, which were used to construct AND, OR and INHIBIT logic gates for the detection of Hg II and Ag I ions. To our knowledge, this is the first time that the C-Ag I -T mismatched base pair has been used for the construction of luminescent assays or logic gates.

A highly diastereoselective three-component inverse-electron-demand aza Diels-Alder reaction assisted by per(poly)fluoro-alkanesulfinamides is presented, providing a broad spectrum of highly functionalized piperidine derivatives with excellent endo/exo and facial diastereoselectivities. The electron-withdrawing perfluoroalkyl groups are crucial for the success of this reaction under mild conditions and facilitate monitoring the process and stereoselectivities of the reaction. The synthetic potential of these cycloadducts is also highlighted.