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A photo-switchable hetero-complementary quadruple H-bonding array, which consists of an azobenzene-derived ureidopyrimidinone (UPy) module (Azo-UPy) and a nonphotoactive diamidonaphthyridine (DAN) derivative (Napy-1), is constructed based on a reversible photo-locking approach. Upon UV (390 nm)/Vis (460 nm) light irradiations, photo-switchable quadruple H-bonded dimerization between Azo-UPy and Napy-1 can be achieved with exhibiting 4.8×104 -fold differences in binding strength (ON/OFF ratios). Furthermore, smart polymeric gels with unique photo-controlled macroscopic self-assembly behavior can be fabricated by introducing such quadruple H-bonding array as photo-regulable noncovalent interfacial connections.

Purpose: To investigate the prevalence and clinical characteristics of myelinated retinal nerve fibre (MRNF) in a large teleophthalmology system.Methods: All records between January 2015 and Decemb...

For the deoxygenation of fatty acids to hydrocarbon biofuels, the catalytic mechanism is still unclear at the molecular level. Here, the deoxygenation mechanism of butyric acid catalyzed by a Ni12P6 cluster has been theoretically studied at the GGA–PBE/DNP, DSPP level in dodecane solution, in which butyric acid and the Ni12P6 cluster are preferred as the reactant model of palmitic acid and the catalyst model of Ni2P, respectively. For the deoxygenation of butyric acid, there are three main reactions i.e., (reaction (I)) through direct decarboxylation to propane, (reaction (II)) through decarbonylation and hydrodehydration/hydroreduction to propane, and (reaction (III)) through hydroreduction and/or hydrodehydration to n-butane. Propane stems from the decarbonylation (reaction (II)) rather than direct decarboxylation (reaction (I)). For reaction (II), the optimal pathway should be through butyraldehyde or direct decarbonylation and not through propyl alcohol. Furthermore, CO mainly originates from butyraldehyde at low temperature and from direct decarbonylation at high temperature. From butyraldehyde, decreasing temperature is beneficial to the n-butyl alcohol formation through hydroreduction, and increasing temperature is preferable to the propane formation through decarbonylation. For reaction (III), from n-butyl alcohol, n-butane comes from direct hydrodehydration at low temperature, and from successive dehydration and hydroreduction through n-butylene at high temperature. The present reaction mechanism network may promote the novel design of a highly selective catalyst toward the deoxygenation of fatty acids.

Al-Containing MCM-41 catalysts exhibit good catalytic activity toward glucose-to-fructose isomerization. However, the catalytic contribution of typical functional groups over Al active sites is a little unclear. Here, on the pore surface of Al-doped MCM-41, there are two different active sites, i.e., –[SiO]2[SiO(H)]Al[OH] ([Al-1]) with one hydroxyl and –[SiO][SiO(H)]Al[OH]2 ([Al-2]) with two hydroxyls. Over these two active sites, the catalytic mechanisms for the isomerization of glucose to fructose have been theoretically studied, combining molecular mechanics and hybrid quantum mechanics calculations. The glucose-to-fructose isomerization usually involves three successive reaction stages, i.e., ring-opening, tautomerization, and ring-closure. Among them, aldose–ketose tautomerization is the rate-determining step, which is related to the intramolecular C2 → C1 H-shift. The catalytic activity of the Al-containing active sites originates from three factors, i.e., the Lewis acidity of the Al site, a proton donor in the form of an Al–O(H)–Si group and a proton acceptor in the form of an Al–OH group. The [Al-2] active site with two hydroxyls displays higher catalytic activity than the [Al-1] active site with one hydroxyl, which mainly depends on the Lewis acidity of the aluminium atom in the active site.

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.

In this paper, a unique orthogonal photoresponsive tristable [3]rotaxane molecular shuttle (R1) is constructed, which consists of two CBPQT4+ macrocycles interlocked via a dumbbell component containing three recognition sites, including photoswitchable azobenzene (AB) and naphthalene-derived azobenzene (NP-AB) units separated by a 1,5-dioxynaphthalene (DNP) unit. The two azo units that are encapsulated by the CBPQT4+ macrocycles in the pristine state can be E/Z photoisomerized separately upon irradiation using UV (365 nm) and yellow (>550 nm) light (for the AB unit) and using blue (420–430 nm) and yellow (>550 nm) light (for the NP-AB unit), thus achieving the distinctive orthogonal phototriggered shuttling of the CBPQT4+ macrocycles between the azo and DNP units. This means that charge transfer (CT) absorption (at 620 nm, generated from the NP⊂CBPQT4+ encapsulation complex) related to R1 can be fully photoregulated between three spectral states with good reversibility. Moreover, UV-light-irradiated [2]rotaxane analogues that are embedded with NP-AB or AB units are found to be insensitive to red light (620 nm) irradiation. These features, together with the peculiarity of the orthogonal photo-responsiveness, enable this novel photochromic [3]rotaxane to be potentially applied as a multistate molecular switch or as an optical information storage medium with non-destructive readout.

Exploring new structures of synthetic two-dimensional (2D) nanomaterials plays a crucial role in the development of such burgeoning materials toward more appealing functions and innovative potentia...

Recently, increasing attention has been paid on extending the π-conjugation structures of viologens (1,1′-disubstituted-4,4′-bipyridylium salts) by incorporating planar aromatic units into the bipyridinium backbones. Various viologen derivatives with extended π-conjugation structures have been synthesized, including the N-termini aromatic substituted viologens, the extended π-conjugated viologens (denoted as ECVs) as well as the π-conjugated oligomeric viologens (denoted as COVs). These compounds typically exhibit interesting properties distinguished from those of an isolated viologen unit, which make them as new class of electron deficient supra-/molecular building blocks in supramolecular chemistry and materials science. In this review, we would like to highlight the recent advances of viologen derivatives with extended π-conjugation structures in versatile applications ranging from electrochromic and energy storage materials, the ECV/COV-based supramolecular self-assembly systems including the linear supramolecular polymers and 2D/3D supramolecular organic frameworks (SOFs), to the viologen-based covalent organic frameworks (COFs)/networks. We hope this review will serve as an in-time summary worthy of referring, more importantly, to provide inspiration in the rational design of novel molecules with unexplored properties and functions.

Zr-containing SBA-15 zeolite (Zr-SBA-15) catalysts show good catalytic performance toward xylose conversion to methyl lactate (ML). Here, we report our study on the catalytic mechanisms for the con...

V-containing catalysts exhibit good catalytic performance toward the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). Here, we report our study on the catalytic mechanism of –(SiO)3V(O) ([V-0]) and –(SiO)2V(O)(OH) ([V-1]) on a V-doped Al-MCM-41 pore model (V/Al-MCM-41) for the aerobic oxidation of HMF to DFF. For the two active sites, there are three types of oxygen-containing functional groups, which are hydroxyl-oxygen ([V–OH]), lattice-oxygen ([V–O–Si]), and terminal-oxygen ([VO]). We show that the catalytic cycle involves two HMF molecules, and there are mainly two activation steps, i.e., both O–H and C–H bond cleavages of HMF, and the rate-determining step is associated with the C–H bond cleavage of the first HMF molecule. We illustrate the efficiency of the catalytic contribution as [V–OH] > [V–O–Si] > [VO], and the [V-1] active site with a hydroxyl group displays higher catalytic activity than the [V-0] active site without a hydroxyl group. The present study not only brings an in-depth understanding of the activation of both O–H and C–H bonds which has been proposed based on experimental results for biomass molecules, but also makes one step forward toward the mechanism-guided design and synthesis of efficient, environmentally-friendly, and low temperature recyclable heterogeneous catalysts.

Apatinib is a new oral tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor-2. It has been proven effective in treating multiple solid tumors. Herein, we report the case of a 67-year-old Chinese patient who was diagnosed with recurrent and malignant transformation of intrahepatic biliary cystadenoma. After multidisciplinary team discussion, the team considered that the remaining liver volume was insufficient for surgical resection. The patient refused chemotherapy and radiotherapy and was willing to take apatinib. Initially, the patient experienced severe tongue ulcers and difficulty eating. The dose of apatinib was then adjusted to 250 mg/day. To date, he has been taking apatinib for 48 months. Regular re-examination showed that the tumor had significantly decreased in size. On January 16, 2021, a CT scan revealed a tumor diameter of 4.5 cm. In our case, the patient achieved partial response and progression-free survival(PFS) of 48.0 months. During treatment, the patient’s appetite and mental state were expected. The treatment did not induce hypertension, fatigue, hand-foot syndrome, or liver and kidney damage. Apatinib may be an option for the treatment of advanced intrahepatic biliary cystadenocarcinoma. Its toxicity is controllable and tolerable. The exact curative effect still needs to be evaluated in more cases.

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., A photolocking strategy is described to achieve the construction of effectively photoswitchable quadruple hydrogen bonds featuring with photoregulable H-bonding affinities, which is further applied in the photocontrollable H-bonded self-assemblies.

It is still not clear at the molecular level how the acidic silanol and basic alkylamine bifunctional groups over SBA-15 zeolite exert catalytic functions in aldol condensation of 5-hydroxymethylfu...

A major limitation in the application of light-responsive host–guest complex-based photoresponsive materials in living organisms is the lack of reliable photocontrollable recognition motifs activated beyond UV light, especially by the light within a biological window (650–1450 nm). Herein, we present long wavelength light-responsive cucurbit[8]uril (CB[8])-mediated binary host–guest complexes, in which the encapsulated photoisomerizable azobenzene-derived guests exhibit high E → Z photoisomerization ratios upon irradiation of yellow (>500 nm) or red (650 nm) lights. The non-irradiated binary host–guest complexes can further serve as supramolecular nanocontainers to uptake second guests (e.g., selected drug molecules). Moreover, “on command” release of the non-photoactive molecular cargos can be triggered by irradiating the resulting CB[8]-mediated heteroternary host–guest complexes with yellow or red lights. Due to activation within the biological window with high photoisomerization ratio, the specific red-light-responsive CB[8]-mediated heteroternary host–guest complexation is expected to be a promising tool in the extensive applications of photopharmacotherapy, drug delivery and biocompatible dynamic materials.

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.

Mo-Containing catalysts exhibit good catalytic performance toward the selective oxidation of platform chemicals from biomass. However, for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), the development of an environmentally-friendly and promising catalytic system remains a significant challenge to date. In the present study, on the pore surface of MCM-41, two kinds of active sites, which are, –(SiO)2Mo(O)2 ([Mo-4]) and –(SiO)3Mo(OH)(O) ([Mo-5]), have been theoretically designed, over which the catalytic mechanisms for the aerobic oxidation of HMF to DFF have been theoretically examined, combining the hybrid quantum mechanics and molecular mechanics calculations. Over both [Mo-4] and [Mo-5] active sites, the oxidative reaction includes two main reaction steps, the O–H and C–H bond cleavages of HMF, in which the crucial reaction step is associated with the C–H bond cleavage of the CH2 group of the first HMF. Over the –(O)4–MoO active site on the Keggin heteropolyacid ([Mo-HPA]), [Mo-4] and [Mo-5] active sites, the MoO group is responsible for the O–H bond activation in the HMF moiety, and the Mo–OH group is in charge of the C–H bond activation in the HMF moiety, both of which take a synergic catalytic effect. The catalytic activity decreases as [Mo-5] > [Mo-4] > [Mo-HPA]. Based on the activation strain analysis, the lowering activation energy stems mainly from the lowering activation strain of the active site, which correlates positively with the corresponding HOMO–LUMO gap. These findings provide deep insight for the rational design of a recyclable catalyst to activate both C–H and O–H bonds at low temperatures, especially for some typical platform molecules from biomass.

Two reduced Schiff bases, namely 5-[(2-hydroxybenzyl)amino]isophthalic acid (1) and 5-[(pyridin-4-ylmethyl)amino]isophthalic acid (2), were synthesized in two-step method using 5-aminoisophthalic acid as the starting material, and were characterized by single-crystal X-ray diffraction, elemental analysis, infrared, 1H NMR, mass, absorption and fluorescence spectra. Both 1 and 2 crystallize in monoclinic system with space groups P21/c for 1 and P21/n for 2. Photophysical properties of both 1 and 2 are significantly different from those of raw material 5-aminoisophthalic acid due to stronger p → π conjugation when one amino hydrogen atom in 5-aminoisophthalic acid is substituted with electron-donor group. 1 displays a very strong narrow-band blue fluorescence with the maximum peak at 439 nm, a high quantum efficiency up to 64%, and a narrow full width at half maximum of 35 nm, while 2 has a broader and weaker fluorescence with the peak at 418 nm and FHWM of about 50 nm. Two reduced Schiff bases with blue fluorescence were synthesized from 5-aminoisophthalic acid in two-step method including formation of the corresponding Schiff bases and further reduction by NaBH4.

Heterogeneous catalysts with hierarchically porous structure are highly efficient to catalyze chemical reactions. In this work, two-dimensional (2D) nano-flakes assembled flower-like NiO is fabricated and utilized for activating peroxydisulfate (PDS) to degrade organic pollutants bisphenol A (BPA). The results demonstrate that the prepared catalyst exhibits well organized flower structure composed of uniform 2D nano-flakes. PDS combines with the catalyst to form surface-activated NiO-PDS complex, subsequently depriving electrons from BPA. For the optimized NiO-12 catalyst, large specific surface area and hierarchically porous structure benefit to exposes abundant active sites while low resistance promotes electrons transfer, bringing the high BPA degradation rate constant of 0.28 min−1 under the condition of 20 mg/L initial concentration. NiO-12 exerts a capability of catalyzing PDS to mineralize 34% of practical packaging wastewater. This study provides a new strategy to fabricate hierarchical 2D porous catalysts for persulfate activation, with application potential in practical wastewater treatment.

The fundamental understanding of the cooperativity of a Bronsted 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 Bronsted acid (H3O+) 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 H3O+, the halide anions (Cl− and Br−) act as promoters, whereas both NO3− 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 graphene oxide (GO)-based pH sensor was designed and prepared through covalently attaching a zwitterionic betaine molecule onto a GO surface. This betaine-modified GO (BMGO) exhibited high water solubility and low toxicity. In aqueous media, BMGO displayed increased fluorescence in acidic conditions and decreased fluorescence in basic conditions. BMGO possesses a pH sensing range from 4 to 12 with excellent reversibility, quick response and high stability. With its high sensitivity and robustness, BMGO can be used to monitor the pH of intracellular contents, as demonstrated through cell imaging.

Background/Aims: Early repolarization syndrome (ERS) has been recently recognized as early repolarization pattern with idiopathic ventricular fibrillation. However, the genetic background of ERS has not been fully understood. Methods: A Chinese family with sudden cardiac death associated with ERS was investigated. Direct sequencing of ERS susceptibility genes was performed on the proband and family members. Whole-cell patch-clamp methods were used to characterize the mutant channel expressed in HEK 293 cells. Results: One missense mutation (p. K801T) was found in the hERG (KCNH2 gene) by the direct sequencing of candidate genes. Whole cell voltage clamp studies of the K801T mutation in HEK 293 cells demonstrated a 1.5-fold increase in maximum steady state current (37.2±7.3 vs 20.3±4.4 pA/pF) that occurred at a 20 mV more positive potential compared to the wild type channels. The voltage dependence of inactivation was significantly shifted in the positive voltage direction (WT -59.5±1.4 vs K801T -44.3±1.2 mV). Kinetic analysis revealed slower inactivation rates of K801T, but faster rates of activation and deactivation. The hERG channel blockers tested inhibited K801T-hERG channel in concentration response, and the potencies of these drugs can be rank-ordered as follows: quinidine> disopyramide> sotalol> flecainide. Conclusion: Our study indicated that the K801T mutation caused the gain of function of hERG channels that may account for the clinical phenotype of ERS. Quinidine and disopyramide could improve the function of K801T-hERG mutant channel, and may be therapeutic options for patients with the K801T hERG mutation.

Low-molecular-weight supramolecular hydrogels are of significant attractive soft materials as particular functions can be facilely introduced by the straightforward fabrication of such self-assembled systems. In this study, an azobenzene-bridged dicationic pyridinium salt was synthesized, from which photoresponsive supramolecular hydrogel could be fabricated through the π-π stacking and hydrophobic interactions in the aqueous solution. By taking advantages of the UV–vis light induced E/Z photoisomerization behaviors of the incorporated azobenzene photochromophore, reversible gel-sol transformation of such supramolecular hydrogel could be achieved under the alternating UV–vis irradiation conditions. We believed that this photoresponsive supramolecular hydrogel will be a good supplementary in the creation of intelligent soft material.

The development of ratiometric fluorescence sensing platforms with simple synthetic routes and good anti-interference capacities are of great importance for their further application. Herein, hyperbranched polyethylenimine passivated carbon dots (HPEI-CDs) with concentration-modulated dual-excitation fluorescence property were synthesized. At a low concentration, HPEI-CDs only showed one fluorescence center, while at a relatively high concentration, its excitation peak around 355 nm would split into two peaks. Energy level splitting and broadening were demonstrated to be the origin of such dual-excitation behavior. Based on the dual-excitation signals, HPEI-CDs could serve as a ratiometric sensor for the detection of Fe3+ in aqueous solution. The assay exhibited a wide linear response concentration range (2–360 μM) with a limit of detection of 0.47 μM. Significantly, benefiting from the high concentration of HPEI-CDs, the sensor showed good selectivity and excellent anti-interference capacity. In addition, this nanosensor was successfully applied for the detection of Fe3+ in real water samples with satisfactory recoveries.

To investigate the effects of central metal ions on the structures and luminescent sensing properties of ternary luminescent coordination polymers, three new complexes, {[Co(L)(TBTA)(H2O)2]·H2O}n (1), {[Zn(L)(TBTA)]·1.9H2O}n (2) and [Cd(L)(TBTA)]n (3) (L = 1,4-bis(5,6-dimethylbenzimidazol-1-yl)-2-butylene, H2TBTA = tetrabromoterephthalic acid), were synthesized and characterized. 1 and 3 reveal a sql layer, whereas 2 displays a hcb network. Three compounds can be used as probes for the sensitive sensing of Fe3+ and Cr2O72− ions by a luminescence quenching process. The limits of detection (LOD) of 1, 2 and 3 for the detection of Fe3+ ions are 1.61, 1.13 and 0.71 μM, respectively, while the LOD for the sensing of Cr2O72− ions are 1.95, 2.31 and 1.84 μM, separately Possible mechanisms for the luminescence quenching process toward Fe3+ and Cr2O72− ions are presented. The central metal ions of the three ternary CPs play a key role for the effective detection of Fe3+ ions.

A vanadium(V) complex, [VO2(tpy)]ClO4 (1, tpy = 2,2′:6′2″-terpyridine), was synthesized and characterized by physicochemical and spectroscopic methods, as well as by single-crystal and powder X-ray diffraction analysis. Complex 1 has a five-coordinate distorted trigonal bipyramidal geometry. The in vitro cytotoxicity of complex 1 was evaluated against cell lines of liver hepatocellular carcinoma HepG-2, cervical cancer HeLa, lung carcinoma A549, osteoma sarcomatosum HOS, hepatocarcinoma BEL-7402 and normal human hepatic cells LO2 by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. The complex displays excellent antitumor activity against the selected cell lines compared with cisplatin and also exhibits lower cytotoxicity toward LO2 cells. Morphological and staining experiments demonstrated that complex 1 induces BEL-7402 cell apoptosis mediated through reactive oxygen species, DNA fragmentation and decrease in mitochondrial membrane potential. In addition, cell cycle distribution investigations showed that complex 1 inhibits cell growth at the G0/G1 phase.

Targeting protein–protein interactions (PPIs) offers tantalizing opportunities for therapeutic intervention for the treatment of human diseases. Modulating PPI interfaces with organic small molecules has been found to be exceptionally challenging, and few candidates have been successfully developed into clinical drugs. Meanwhile, the striking array of distinctive properties exhibited by metal compounds renders them attractive scaffolds for the development of bioactive leads. Here, we report the identification of iridium(III) compounds as inhibitors of the H-Ras/Raf-1 PPI. The lead iridium(III) compound 1 exhibited potent inhibitory activity against the H-Ras/Raf-1 interaction and its signaling pathway in vitro and in vivo, and also directly engaged both H-Ras and Raf-1-RBD in cell lysates. Moreover, 1 repressed tumor growth in a mouse renal xenograft tumor model. Intriguingly, the Δ-enantiomer of 1 showed superior potency in the biological assays compared to Λ-1 or racemic 1. These compounds could potentially be used as starting scaffolds for the development of more potent Ras/Raf PPI inhibitors for the treatment of kidney cancer or other proliferative diseases.

Novel visible-light responsive hydrogen-bonded supramolecular polymers have been successfully constructed by using a linear molecule, which consists of two ureido-pyrimidinone (UPy) moieties connected by a photochromic ortho-tetrafluorinated azobenzene (TFAB) linker. Benefiting from the visible-light responsive feature of the TFAB unit, reversible photoisomerization between the two isomers of the monomer can be achieved. The E-isomer prefers to form a linear supramolecular polymer through the intermolecular quadruple hydrogen bonding interactions between UPys, whereas the Z-isomer facilely forms a cyclic dimer. Therefore, the polymerization mechanisms and properties of such supramolecular polymers, e.g. reversible visible-light induced gel–sol transformation behaviour, can be regulated by the reversible visible-light triggered E/Z photo-isomerization of the TFAB chromophore.

Purpose To study the retinal oxygen saturation in normal eyes of Chinese adolescents. Methods Performing retinal oximetry with the Oxymap T1 Retinal Oximeter in healthy children and adolescents (aged 5–18 years old), we measured the arterial (SaO2) and venular (SvO2) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO2). Results The study included 122 individuals with a mean age of 13.0 ± 2.9 years (range: 5–18 years) and a mean refractive error of −3.25 ± 2.49 dioptres (range:−8.88 to +3.13 dioptres). Mean SaO2, SvO2 and Sa-vO2 was 85.5 ± 7.1%, 48.2 ± 5.5% and 37.3 ± 6.5%, respectively. Mean SaO2 was significantly (p 0.05) between the fundus quadrants. In multiple linear regression analysis, SaO2 increased (regression coefficient r2 = 0.28) with older age (standardized regression coefficient β: 0.23; p = 0.01) and more myopic refractive error (β: −0.39; p

α-Amino phosphinates with P , C -stereogenic centers were prepared from a P -retained addition of ( R P )-(−)-menthyl H -phenylphosphinate to ( R )-aldimines with up to 86:14 dr under catalyst and solvent free condition at ambient temperature; the single ( S P , S α-C )-stereoisomers were isolated in moderate yields. Chirality on the nitrogen of chiral aldimine was proposed to control the stereoselectivity, and the (−)-menthoxyl showed mismatched asymmetric induction with ( S )-aldimines.

Background The transforming growth factor β (TGFβ) and bone morphogenetic protein (BMP) signaling pathways are both constitutively activated in triple-negative breast cancer (TNBC). We are interested in isolating the naturally-derived small-molecule inhibitor that could simultaneously targeting TGFβ/BMP pathways and further studying its anti-proliferative/−metastatic effects as well as the underlying mechanisms in multiple tumor models. Methods Multiple in vitro cell-based assays are used to examine the compound’s inhibitory efficacy on TNBC cell growth, stemness, epithelial-mesenchymal transition (EMT), invasion and migration by targeting TGFβ/BMP signaling pathways. Transgenic breast cancer mouse model (MMTV-PyMT), subcutaneous xenograft and bone metastasis models are used to examine ZL170’s effects on TNBC growth and metastasis potentials in vivo. Results ZL170 dose-dependently inhibits cell proliferation, EMT, stemness, invasion and migration in vitro via specifically targeting canonical TGFβ/BMP-SMADs pathways in TNBC cells. The compound significantly hinders osteolytic bone metastasis and xenograft tumor growth without inflicting toxicity on vital organs of tumor-bearing nude mice. ZL170 strongly inhibits primary tumor growth and lung metastases in MMTV-PyMT transgenic mice. ZL170-treated tumors exhibit impaired TGFβ/BMP signaling pathways in both epithelial and stromal compartments, thereby creating a suppressive tumor microenvironment characterized by reduced extracellular matrix deposition and decreased infiltration of stromal cells. Conclusions ZL170 inhibits tumor EMT, stemness and metastasis and could be further developed as a potent anti-metastatic agent used in combination with cytotoxic drugs for treatment of TNBC and other advanced metastatic cancers. Electronic supplementary material The online version of this article (10.1186/s13046-019-1130-2) contains supplementary material, which is available to authorized users.

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.

Epigenetic mechanisms have emerged as key targets for therapeutic intervention. However, while a number of organic small-molecular “epidrugs” have been approved for clinical use, no metal-based epigenetic modulator have been successfully approved. Metal complexes exhibit a variety of distinct properties that make them viable alternatives to organic molecules as therapeutic agents. In this review, we highlight recent examples of epigenetic modulation by metal complexes, with a view towards showcasing the different mechanisms exploited by metal complexes for targeting either epigenetic marks or epigenetic pathways for potential therapeutic applications.

Inactivation of the p53 transcription factor by mutation or other mechanisms is a frequent event in tumorigenesis. One of the major endogenous negative regulators of p53 in humans is hDM2, a ubiquitin E3 ligase that binds to p53 causing proteasomal p53 degradation. In this work, a library of organometallic iridium(III) compounds were synthesized and evaluated for their ability to disrupt the p53/hDM2 protein-protein interaction. The novel cyclometallated iridium(III) compound 1 [Ir(eppy)2(dcphen)](PF6) (where eppy = 2-(4-ethylphenyl)pyridine and dcphen = 4, 7-dichloro-1, 10-phenanthroline) blocked the interaction of p53/hDM2 in human amelanotic melanoma cells. Finally, 1 exhibited anti-proliferative activity and induced apoptosis in cancer cell lines consistent with inhibition of the p53/hDM2 interaction. Compound 1 represents the first reported organometallic p53/hDM2 protein-protein interaction inhibitor.

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.

The variable mechanism for substitution of P-stereogenic phosphoryl chloride with alkynyl metallic reagents, which depends on temperature, stoichiometry of starting materials, and the structure of the nucleophilic reagent, is assumed as either SN2-like or Berry pseudorotation of pentacoordinated phosphorus intermediates, affording inversion and retention products, respectively. The formation of the inversion product can be controlled to occur predominantly to afford (RP)-alkynylphosphinates.

A new photo-responsive tetracationic macrocycle was designed and synthesized by connecting two bis(imidazolium)-tetrachloro-azobenzene units with o-xylene linkers. The ability of red-light triggered photoisomerization of the incorporated tetrachloroazobenzene units has featured this macrocycle with reversible photo-triggered configurational transformation, benefiting from which the distinctive red-light regulated encapsulation behavior for aromatic dicarboxylic dianions in DMSO solution could be achieved.

Pulmonary fibrosis is a prototypic chronic progressive lung disease with high morbidity and mortality worldwide. Novel effective therapeutic agents are urgently needed owing to the limited treatment options in clinic. Herein, nagilactone D (NLD), a natural dinorditerpenoid obtained from Podocarpus nagi, was found to suppress transforming growth factor-β1 (TGF-β1)-mediated fibrotic process in vitro and bleomycin (BLM)-induced pulmonary fibrosis in vivo. NLD attenuated TGF-β1-induced expression of fibrotic markers including type I and III collagen, fibronectin, α-SMA, and CTGF in human pulmonary fibroblasts (WI-38 VA-13 and HLF-1 cells). Mechanism study indicated that NLD suppressed TGF-β1-induced up-regulation of TβR I, and Smad2 phosphorylation, nuclear translocation, and transcriptional activation. Moreover, NLD ameliorated BLM-induced histopathological abnormalities in the lungs of experimental fibrotic mice, suppressed synthesis of relative fibrotic markers and fibroblast-to-myofibroblast transition, as well as BLM-induced up-regulation of TβR I expression and Smad signaling in mouse lungs. These data collectively support NLD to be a potential therapeutic agent for pulmonary fibrosis.

The development of artificial self-assembling systems with dynamic photo-regulation features in aqueous solutions has drawn great attention owing to the potential applications in fabricating elaborate biological materials. Here we demonstrate the fabrication of water-soluble cucurbit[8]uril (CB[8])-mediated supramolecular polymers by connecting the fluorinated azobenzene (FAB) containing monomers through host-enhanced heteroternary π-π stacking interactions. Benefiting from the unique visible-light-induced E→Z photoisomerization of the FAB photochromophores, the encapsulation behaviors between the CB[8] macrocycle and the monomers could be regulated upon visible light irradiation, resulting in the depolymerization of such CB[8]-mediated supramolecular polymers.

A yellow-pigmented bacterial strain (JR1T) isolated from a sediment sample was subjected to a taxonomic study, based on phenotypic, genetic and physiological characterization. Here, we describe the cultivation and characteristics of strain JR1T, a novel member of the genus Carboxylicivirga in the family Marinilabiliaceae . Cells of strain JR1T were rod-shaped, Gram-stain-negative, non-motile and facultatively anaerobic. The temperature range for growth was 15–42 °C (optimum, 33 °C) and the pH range for growth was pH 6.0–8.5 (optimum, pH 7.0–7.5). Growth occurred in the presence of 0.0–10.0 % (w/v) NaCl (optimum 2.0–3.0 %). 16S rRNA gene sequence analysis produced results with 97.4 % similarity to Carboxylicivirga taeanensis MEBiC 08903T, 96.8 % similarity to Carboxylicivirga mesophila MEBiC 07026T, 94.9 % similarity to Carboxylicivirga linearis FB218T and 94.6 % similarity to Carboxylicivirga flava Q15T. The DNA G+C content was 42.3 mol% and the major fatty acids were iso-C15 : 0, C15 : 0, anteiso-C15 : 0, C17 : 1ω6c and iso-C17 : 0-3OH. The major polar lipids detected were phosphatidylethanolamine and two unidentified lipids; the major respiratory quinone detected was MK-7. The results of the phenotypical, phylogenetic and biochemical analyses between the study strain and some related type strains indicated that this strain represent a novel species of the genus Carboxylicivirga within the family Marinilabiliaceae , for which the name Carboxylicivirga sediminis sp. nov. is proposed. The type strain is JR1T (=MCCC 1K03323T=KCTC 52869T).

Nucleophilic substitutions at P centers are of high importance in biological processes and asymmetric synthesis. However, detailed studies on this topic are rare. P-Stereogenic compounds containing P–Cl, P–O, and P–S bonds were diastereoselectively prepared and then used to study the substitution of Cl, O, and S at phosphorus centers with organometallic reagents. It was proposed that with alkynyl metallic reagents an SN2-like mechanism (route A1) and a Berry pseudorotation (BPR) of pentacoordinated phosphorus intermediates (route B1) were involved and afforded P-inverted and P-retained products, respectively. The P-inverted conversion of a P–Cl functionality to a P–C functionality can be controlled by either the temperature or the order of addition of the starting materials. The introduction of a P–Cl bond using an alkyl metallic reagent proceeded through routes A2 and A2′. At higher temperatures, P-inverted products were predominantly afforded via SN2-like route A2. At lower temperatures, bis-substituted...

A library of six luminescent Ir(III) complexes were synthesized and studied for their capacity to function as probes for G-quadruplex DNA. The novel Ir(III) complex 1 was discovered to be selective for G-quadruplex structures and was subsequently used for the construction of a label-free G-quadruplex-based ochratoxin A (OTA) sensing platform in aqueous solution. The assay exhibited linearity for OTA in the range of 0 to 60 nM (R2 = 0.9933), and the limit of detection for OTA was 5 nM. Furthermore, this assay was highly selective for OTA over its structurally related analogues.

Phenyl dichlorophosphine reacted with (L)-(–)-menthol to afford two diastereomers of menthyl phenylphosphinate (RP)-1a/(SP)-1a′ in up to 89:11 dr. Compound (RP)-1a was isolated in 58 % yield (60 g) and > 99:1 dr. An HCl-promoted diastereoselective hydrolysis of the P–Cl species was found to be involved in the reaction. On the basis of this, a mixture of 1a/1a′ with 50:50 dr was converted to a mixture enriched in 1a with 88:12 dr by treatment with phosphorus trichloride.

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.

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).

Tumor necrosis factor α-converting enzyme (TACE) plays a critical role in diverse physiological processes such as inflammation, hematopoiesis, and development. In this study, a pharmacophore model constructed from a training set of TACE inhibitors was used to screen an in-house database of organic compounds, from which compound 1 emerged as a top candidate. In a cell-free assay, compound 1 inhibited TACE enzymatic activity in a dose-dependent manner. Moreover, compound 1 inhibited the production of soluble TNF-α in human acute monocytic leukemia THP-1 cells without impacting nitric oxide production, and exhibited anti-proliferative activity against THP-1 cells. We envisage that compound 1 may be employed as a useful scaffold for the development of more potent TACE inhibitors. This study also validates the use of pharmacophore modeling to identify enzyme inhibitors. ASTAR (Agency for Sci., Tech. and Research, S’pore)

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.

Zinc promoted asymmetric Barbier-type homopropargylation of aldimines is demonstrated. 2-Chlorotetrafluoroethanesulfinamide was used as the chiral auxiliary and the corresponding homopropargylamines were obtained in good yields with up to 98% diastereoselectivity under mild conditions.