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Described herein is a copper-catalyzed efficient oxidative dearomatized functionalization of indoles by using alcohols as the nucleophiles. Various 3-alkoxy-2-oxindoles were accessible with good isolated yields. The synthetic potential applications are demonstrated by the large-scale reaction, as well as the derivatization of the desired 3-alkoxy substituted-2-oxindole products.

An efficient three-component radical iodosulfonylative cyclization of enynes is described. The visible-light irradiation of iodoform with sulfinates enables sulfonyl radical generation under catalyst- and oxidant-free conditions and triggers the radical addition, cyclization and iodination cascade reactions, giving various vinyl iodide containing sulfones in moderate to good yields.

A copper-catalyzed bromo-cyanomethylative cyclization of 1,6-enynes is demonstrated. The treatment of 2-bromoacetonitrile with CuI enables the alkyl radical generation and triggers the radical addition/cyclization/bromination sequence, giving various vinyl C-Br bonds containing functionalized heterocycles in good yields.

Described herein is a stereo- and regioselective

Three protein microenvironment-sensitive pillar[5]arene-based fluorescent probes (3/4/5C-B) were designed and synthesized based on intramolecular charge transfer (ICT) mechanism. Unlike the majority of micromolecular ICT probes, the aforementioned probes displayed differentiated sensitivity to multiple proteins. The 7-(diethylamino)coumarin-3-formic acid (DCCA) group in the probes was essential for their sensitivity. The presence of a pillar[5]arene group was also crucial as they benefit 3/4/5C-B form complexes with the proteins, although it changed the electron density distribution of the DCCA group. 3/4/5C-B exhibited favorable carrier ability for regorafenib (REG). 4C-B had the best spatial structure for complexation. The 3/4/5C-B-REG complexes would assemble into high drug-loading fluorescent nanoparticles in a physiological environment (pH = 7.4). Such nanoparticles exhibited pH-triggered enrichment ability, which rapidly enriched REG in the acidic environment (pH = 6.0). Moreover, the complexation between 3/4/5C-B and REG maintained the live-cell membrane imaging property of the probes and the excellent targeted anticancer activity of the drug.

The fluorinative alkoxylation of simple alkenes under catalyst-free conditions was achieved. Various substituted olefins, including terminal and internal alkenes, and oxygen-containing nucleophiles were compatible with the standard conditions, and gave a variety of β-fluoroethers in good to excellent yields. Notably, the alkynyl and chloride-containing nucleophiles were well tolerated. In addition, acetic acid and TsNH2 could be also used as nucleophiles and successfully afforded the desired products in good yields.

A novel fluorescent chemosensor of the derivatives of calix[4]arene (SAX) for Congo red (CR) in methyl-β-cyclodextrin/Triton X-100 synergistic sensitized system was developed. The results showed that the fluorescence intensity of SAX could be quenched by CR, and the fluorescence quenching (∆F = FSAX − FCR-SAX) was synergistic sensitized by methyl-β-CD and Triton X-100. Under the conditions of λex/em = 332/468 nm and pH 7.5, the linear range and the detection limit for CR were found to be 0.040–8.0 μg/mL and 8.9 ng/mL, respectively. The mechanism of determination was discussed by quenching type analysis and sensitizing effect. This method has also been applied for the determination of CR in beef samples with satisfactory results.

Calixarenes and their derivatives are the third generation of macrocyclic hosts in supramolecular chemistry. They are an extremely versatile class of macromolecules due to their superior geometric shapes, excellent flexibility, improved conformational mobility, easily modification and no immune response in vivo. Additionally, they could be functionalized by some groups with good water solubility or biological activity on the upper or lower rim to obtain the derivatives that can be used as the carrier for drugs. P-tert-butyldihomooxacalix[4]arene is a well-known calix[4]arene analog in which one CH2 bridge is replaced by one -O- group. Thus, dihomooxacalix[4]arene has slightly larger cavity than that of calix[4]arene and usually possesses a more flexible cone conformation and the bridged oxygen atom might provide additional binding sites. On the other hand, gels are interesting soft materials owing to their functional properties leading to potential applications. Using gels as drug carriers have attracted tremendous attention for their mumerous advantages to medical treatments, including prolonged drug release time, reduced side effects of drugs and maintain effective plasma concentration. Unfortunately, molecular gels based on p-tert-butyldihomooxacalix[4]arene are rarely reported. Here, we synthesized new functional p-tert-butyldihomooxacalix[4]arene 1 through Ugi reaction in good yield (70%), starting from condensed p-tert-butyldihomooxacalix[4]arene O-alkoxy-substituted benzaldehydes, benzoic acid, benzylamine, and cyclohexyl isocyanide. The soft gel was prepared by adding the 1 into cyclohexane directly. It shows remarkable thermoreversibility and can be demonstrated for several cycles. As is revealed by SEM images, xerogel showed highly interconnected and homogeneous porous network structures, and hence the gel is suitable for storage and controlled release.

A novel surfactant sensitized fluorescent chemosensor for safranine T (ST) based on calixarene-1,3-diacyl hydrazone (CADH) in sodium dodecyl sulfate (SDS) medium was investigated. The fluorescence intensity of CADH was quenched by ST due to the formation of weak fluorescent inclusion complex (ST-CADH), and the fluorescence quenching (Δ F = F CADH − F ST-CADH ) was sensitized in SDS. Under the optimal conditions, the linear range of calibration curve for the determination of ST was 0.02–3.00 μg/m and the detection limit estimated 0.015 μg/mL with RSD 2.2% ( n = 3, c = 1.0 μg/mL). The mechanism of determination was discussed with the fluorescence quenching type, the inclusion of CADH with ST and surfactant sensitized effect. This method has been applied for the detection of ST in real samples with satisfactory results.

A fluorescent chemosensor for paeonol based on tetramethoxy resorcinarene tetraoxyacetic acid (TRTA) in hexadecyltrimethylammonium bromide (CTAB) medium was investigated. The fluorescence of TRTA was quenched by paeonol due to the formation of weak fluorescent inclusion complex (Paeonol–TRTA), and the fluorescence quenching (Δ F = F TRTA − F Paeonol–TRTA ) was sensitized in CTAB. Under the optimal conditions, the linear range of calibration curve for the determination of paeonol was 0.02–6.40 μg/mL. The detection limit estimated and RSD was 12.05 ng/mL, 2.57% ( n = 3, c = 1.0 μg/mL). The mechanism of determination was discussed by quenching type analysis, absorption spectrum titrations, Benesi–Hildebrand method, fluorescence quantum yield and IR spectra. This method has also been applied for the determination of paeonol in real sample with satisfactory result.

Fluorescence quenching by copper(II) of a Schiff base derivative of p-tert-butylcalix[4]arene (SANCAX) in 0.1% polyethylene glycol tert-octylphenyl ether (Triton X-100) medium was investigated. The fluorescence of SANCAX is quenched by Cu2+ due to the formation of a weaker fluorescent inclusion complex (Cu-SANCAX). The fluorescence quenching (ΔF = FSANCAX − FCu-SANCAX) is sensitized in Triton X-100. Under optimal conditions, the linear range calibration curve for the determination of Cu2+ is 0.005–0.08 μg mL−1. The detection limit is 3.05 ng mL−1 with an RSD of 1.55% (n = 3, c = 0.05 μg mL−1). The SANCAX fluorescence quenching mechanism was investigated by the Benesi–Hildebrand method, fluorescence quantum yield, and IR. The method has been applied in the determination of trace Cu2+ in real samples with satisfactory results.

The surfactant sensitized spectrofluorimetry for speciation of chromium (Cr(VI)/Cr(III)) was developed. The analytical procedure was that the fluorescence intensity of l4,10,16,22-tetramethoxyl resorcinarene carboxylic acid derivatives (TRCA) could be selectively quenched by Cr(VI) and the fluorescence quenching value (ΔF=FTRCA-FCr(VI)-TRCA) was increased in cetyltrimethylammonium bromide (CTAB). The main influence factors on the fluorescence quenching (ΔF) were investigated in detail. Under the optimal conditions, the linear range of calibration curve for the determination of Cr(VI) was 0.10~5.00 μg/mL, and the detection limit was 0.024 μg/mL with RSD=2.10% (c=1.0 μg/mL, n=3). The concentration of Cr(III) was calculated by subtracting Cr(VI) from the total chromium determined after oxidizing Cr(III) to Cr(VI). The preliminary sensitized mechanism was discussed with the inclusion constant (K) of TRCA-Cr(VI), the fluorescence quantum yield of TRCA, and IR spectra characterization. The method has been applied to the speciation analysis of Cr(VI)/Cr(III) in water samples.

Different Lewis acids were screened to catalyze the reaction of 2-amino-thiophene-3-carboxylate, orthoformate and aryl amine to form 2-substituted thieno[2,3-d]pyrimidin-4(3H)-one. Zn(OAc)2 was demonstrated to efficiently catalyze the reaction. 20 substituted thieno[2,3-d]pyrimidines were synthesized by adding 0.5% mol Zn(OAc)2 as catalyst under microwave irradiation.

Sodium periodate efficiently catalyzed the three-component Biginelli reaction of an aldehyde, α β-keto ester or β-keto ketone, and urea or thiourea at room temperature under solvent-free conditions and afforded the corresponding 3,4-dihydropyrimidine-2-(1H)-ones in excellent yields.

A series of aryl pyrogallol[4]arenes were efficiently synthesized in excellent yields by cyclocondensation of pyrogallol with aromatic aldehydes under microwave irradiation. The structures of aryl pyrogallol[4]arenes were confirmed by characterization of their acylated derivatives. Under microwave irradiation, alkylation reactions of aryl pyrogallol[4]arenes with some alkylating reagents such as n-butyl iodide, benzyl chloride, and ethyl α-chloroacetate were also finished quickly to yield fully O-alkylated products. The 1H NMR spectra and crystal structures showed that the acylated and alkylated aryl pyrogallol[4]arenes existed mainly in rctt (cis–trans–trans) configuration.

Second–generation calix[4]resorcinarene-based dendrimers containing 16 or 24 terminal salicylideneimines were synthesised by divergent method in five steps from the corresponding calix[4]resorcinarenes.

In this paper, the interaction of safranine T (ST) and calix[4]arene (4,10,16,22-tetramethoxylresorcinarene carboxylic acid derivatives (TRCA)) was investigated with fluorescence spectroscopy. The results was shown that the fluorescence intensity of TRCA could be quenched by ST, and the fluorescence quenching (ΔF=FTRCA-FST-TRCA) was sensitised in cetyltrimethyl ammonium bromide (CTAB). Under the optimal conditions, the linear range of calibration curve for the determination of ST was 0.10-4.00 μg/mL. The detection limit and RSD was 0.034 μg/mL, 2.30% (n=3). The quantum yield (Yu) of ST was approximately 2.0 times higher in the presence of CTAB than that in the absence of CTAB. The method has been applied for the determination of ST in food samples with satisfactory results.

The tetranion ligand η7 -C2 B10 H124- has been observed for the first time in 1, which was obtained from the reaction of o-C2 B10 H12 with excess K metal followed by treatment with UCl4 . As shown in the picture (without K cations and coordinated THF molecules), 1 is a centrosymmetric dimer with a bent sandwich structure.

The tetranion ligand η

Five Zn(II) coordination polymers, [Zn(1,2,3-Hbtc)(1,4-bix)]·0.5(1,4-bix)·H2O (1), [Zn(mocip)(1,4-bix)] (2), [Zn3(1,2,3-btc)2(4,4′-bpy)2(H2O)2]2·7H2O (3), [Zn3(1,2,3-btc)2(bbi)3]2·3H2O (4) and [Zn(dmcaip)(1,3-bix)]·DMF (5), were prepared by hydro(solvo)thermal reactions of ZnO with 1,2,3-H3btc (1,2,3-H3btc = 1,2,3-benzenetricarboxylic acid) in the presence of different N-donor ligands (1,4-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, 4,4′-bpy = 4,4′- bipyridine, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), 1,3-bix = 1,3-bis(imidazol-1-ylmethyl)benzene, H2mocip = 2-(methoxycabonyl)isophthalic acid and H2dmcaip = 2-(dimethylcarbamoyl)isophthalic acid). Their crystal structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses and IR spectra. Complex 1 has a one-dimensional (1D) infinite tubular structure, whereas 2 exhibits two-dimensional (2D) supramolecular networks assembled from 1D chains and 1,4-bix. The three-dimensional (3D) framework of 3 can be described as a trinodal 4-connected (42·64)2(65·8)(42·64)2 topology, which consists of 2D [Zn3(1,2,3-btc)2] layers and 4,4′-bpy pillars. Complex 4 features a 5-nodal (3,4)-connected 3D coordination net with a (6·74·8)2(62·72·82)(6·72)2 topology. Complex 5 has a rare 1D double meso-helical supramolecular structure. Interestingly, in the complexes 2 and 5, the starting 1,2,3-H3btc reagents are converted into new ligands (mocip2− in 2 and dmcaip2− in 5) under solvothermal conditions via in situ ligand reactions. Moreover, thermal stabilities, X-ray powder diffraction and the fluorescent properties of complexes 1–5 have been investigated.

Four novel d10 metal–organic frameworks based on rigid 3,3′,5,5′- azobenzenetetracarboxylic acid (H4abtc) in the presence of auxiliary 2,2′-biimidazole (biim), 1,10-phenanthroline (phen) and pyridine (py) have been synthesized under hydrothermal conditions and structurally characterized. Their formulae are [Cd2(abtc)(biim)2]n (1), {[Cd(abtc)0.5(phen)]4·4H2O}n (2), {[Zn(abtc)0.5(phen)]4·2H2O}n (3) and [Zn3(abtc)(py)4(OH)2]n (4). Complex 1 possesses a one-dimensional (1D) infinite tubular structure by using biim as auxiliary ligand. The structures of complexes 2 and 3 exhibit three-dimensional (3D) (4,4)-connected frameworks with (4284) topologys by employing phen as auxiliary ligands. By utilizing py as auxiliary ligand, complex 4 is a (2,3,4)-connected framework with a (10)(83)2(8,105) topology in which there exists -{Zn-O-Zn}- zigzag chains and 46-member macrocycles which are linked by multicarboxylate ligands to form a 3D supramolecular structure. The structural differences among 1–4 indicate the importance of the auxiliary ligands for the framework formation of the coordination polymers. In addition, the thermal stabilities and photoluminescence properties of 1–4 are also investigated.