Multi-responsive luminescent sensitivities of two pillared-layer frameworks towards nitroaromatics, Cr2O72-, MnO4- and PO43- anions

Combining Zn(II) with two dicarboxylic acids of different length and functional groups results in the 2D metal-carboxylate layer of different size and shape, which are further connected by the same bis-pyridyl-bis-amide pillar to afford two 4-fold and 3-fold interpenetrating pillared-layer networks (1 and 2). Luminescent properties of 1 and 2 have been systematically investigated and demonstrated multi-responsive luminescent sensitivities. 1 can be used for highly sensitive detection of nitroaromatics. In particular, 2 can be used turn-off sensing towards Cr₂O₇^2- and MnO₄^- anions as well as turn-on sensing towards PO₄^3- anion in aqueous solution with high sensitivity and remarkable recyclability. The sensing mechanism is also discussed.

TMSOTf-mediated Kröhnke pyridine synthesis using HMDS as the nitrogen source under microwave irradiation

An efficient protocol for the preparation of pyridine skeletons has been successfully developed involving the TMSOTf/HMDS (trifluoromethanesulfonic acid/hexamethyldisilane) system for the intermolecular cyclization of chalcones under MW (microwave) irradiation conditions. This method provides a facile approach to synthesize 2,4,6-triaryl or 3-benzyl-2,4,6-triarylpyridines in good to excellent yields. Interestingly, the 2,6-diazabicyclo[2.2.2]oct-2-ene core was obtained by changing the acid additive to Sn(OTf)2, and the desired product was also confirmed using X-ray single-crystal diffraction analysis.

Fluoranthene dyes for the detection of water content in methanol

Three novel fluoranthene dyes were obtained by cycloaddition reactions using acrylonitrile and dialkyl acetylenedicarboxylates. Their fluorescence properties in different polar-organic solvents were investigated systematically. Meanwhile, spectral changes induced by the addition of water in methanol were observed, indicating that these fluoranthenes dyes can be efficiently used to detect the water content in methanol as probes. Significantly, the practical test measurements for the water contents in methanol illustrated the measured results with the three fluorescent probes were basically consistent with the water content added artificially. This demonstrated the potential of these fluoranthene dyes as probes in measuring the water content in methanol.

Recent advances and future challenges in the synthesis of 2,4,6-triarylpyridines

2,4,6-Triarylpyridines are key building blocks to access functional molecules that are used in the design of advanced materials, metal-organic frameworks, supramolecules, reactive chemical intermediates and drugs. A number of synthetic protocols to construct this heterocyclic scaffold have been developed to date, the most recent of which (2015-present) are included and discussed in the present review. An emphasis has been placed on the utility of each synthetic approach in view of the scope of aryl/hetaryl substituents, limitations and an outlook of each method to be used in applied sciences.

Insight into the Construction of (3,6)-Connected rtl, ant, and Chiral anh Nets Based on Structural Investigation of Several MOFs via Steric Tuning of Linkers

Six cobalt-organic frameworks (1-6) were solvothermally constructed with a tritopic pyridine-carboxylate linker (L-H) and its methyl- and methoxy-functionalized derivatives (L-OCH₃ and L-CH₃). Due to incorporated multiple substituents with various steric hindrances, the tritopic linkers adopt different molecular configurations, Y-shaped and T-shaped, which further combine octahedral or trigonal-prismatic inorganic nodes to afford diverse (3,6)-connected nets. Consequently, 1 and 2 are rtl nets and 3 and 4 are ant nets. Notably, 5 and 6 present rarely observed chiral anh (flu-3) networks with left-handed double helical chains. The structural investigation indicates that the steric tuning of linkers may essentially dictate the resulting diverse MOF structures. Furthermore, the MOFs presented here can be regarded as an ideal structural platform for a better understanding of the assembly of (3,6)-connected rtl, ant, and chiral anh nets, which are closely related to the shape and geometric configuration/conformation of tridentate organic nodes as well as inorganic building nodes.

A multifunctional Cd(ii)-based metal–organic framework with amide groups exhibiting luminescence sensing towards multiple substances

By incorporating flexible amide group onto skeleton of a tetracarboxylate linker endows it with potential to serve as tetrahedral node and facilitate the construction of a flu net, which significantly demonstrates multi-responsive behavior.

A water-soluble fluorescent probe for detecting creatinine in totally aqueous media and imaging exogenous creatinine in living cells

The design of vigorous tools for creatinine determination is extremely important in the diagnosis and treatment of kidney diseases. In the study, we examine a robust fluorescent turn-on probe (NCP-Pd) for creatinine detection in a completely aqueous solution based on the metal palladium-catalyzed reaction. In the presence of creatinine, the NCP-Pd dissociates and subsequently restores the fluorescence due to elimination of the heavy atom quenching effect and prevention of the photoinduced electron transfer effect. The probe NCP-Pd displays excellent detecting performance with respect to creatinine such as good water solubility, high selectivity, and a low detection limit (0.16 μM). Additionally, in order to ensure its clinical application, this probe is operated in blood serum samples for detecting creatinine and compared with a commercial clinical method. The results indicate an extremely high agreement with the commercial clinical method. Furthermore, the results confirm that the probe NCP-Pd exhibits satisfactory cell permeability and low cytotoxicity and can detect creatinine in L929 and HCT116 cells. The study provides a potential application for detecting creatinine and conducting pathological research on creatinine-involved diseases.

Amide-functionalized ionic indium–organic frameworks for efficient separation of organic dyes based on diverse adsorption interactions

Two amide groups functionalized anionic indium–organic frameworks demonstrated efficient separation of organic dyes based on diverse adsorption interactions, and can be potentially applicable in column-chromatographic separation of dyes.