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Iridium-catalysed regioselective C–H alkynylation of unprotected primary benzylamines and aliphatic aldehydes has been developed using in situ-installed aldimine directing groups.

This work describes a photocatalytic redox-neutral arylation of cyclopropanols with cyanoarenes via radical-mediated C–C and C–CN bond cleavage to afford various β-arylated ketones.

Site-selective C–H silylation has emerged as an efficient tool that can be used to simplify the synthesis of organosilicon compounds; however, catalytic para-selective C–H silylation of electron-deficient arenes has remained a much less explored area. Herein, we report an iron-enabled para-selective C–H silylation of benzamide derivatives with chlorosilanes, which constitutes an efficient and general route for the synthesis of a wide range of para-silicon functionalized benzamides from easily accessible starting materials.

A simple silver-catalyzed regioselective deuteration of (hetero)arenes and α-deuteration of 2-alkyl azaarenes has been described. This strategy provides an efficient and practical avenue to access various deuterated electron-rich arenes, azaarenes and α-deuterated 2-alkyl azaarenes with good to excellent deuterium incorporation utilizing D2O as the source of deuterium atoms.

Upconversion core–shell nanoparticles have attracted a large amount of attention due to their multifunctionality and specific applications. In this work, based on a NaGdF4 sub-10 nm ultrasmall nanocore, a series of core–shell upconversion nanoparticles with uniform size doped with Yb3+, Er3+ and NaDyF4 shells with different thicknesses were synthesized by a facile sequential growth process. NaDyF4 coated upconversion luminescent nanoparticles showed an obvious fluorescence quenching under excitation at 980 nm as a result of energy resonance transfer between Yb3+, Er3+ and Dy3+. NaGdF4:Yb,Er@NaDyF4 core–shell nanoparticles with ultrathin layer shells exhibited a better T1-weighted MR contrast.

It is a significant challenge to develop nanoscale magnetic resonance imaging (MRI) contrast agents with high performance of relaxation. In this work, Gd3+-doped CaF2-based core–shell nanoparticles (CaF2:Yb,Er@CaF2:Gd) of sub-10 nm size were controllably synthesized by a facile sequential growth method. The as-prepared hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles modified using PEG-PAA di-block copolymer benefited from the presence of Gd only in the outer CaF2 layer of the nanoparticles, which exhibited r1 as high as 21.86 mM−1 s−1 under 3.0 T, seven times as high as that of commercially used gadopentetate dimeglumine (Gd-DTPA). Low cytotoxicity, no hemolysis phenomenon and no potential gadolinium ion leakage phenomenon of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles have been observed and confirmed. Clear vascular details can be observed in magnetic resonance angiography and obvious MR signal of 4T1 tumor area could be significantly improved by intravenous injection of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles at a low dosage in mice. A series of in vivo biological safety evaluations confirmed the good biocompatibility of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles, which might be employed in clinical blood pool imaging and tumor diagnosis as a safe and efficient MRI probe.

As the implications of reactive oxygen species (ROS) are elucidated in many diseases, ROS-responsive nanoparticles are attracting great interest from researchers. In this work, a ROS sensitive thioketal (TK) moiety with a π-conjugated structure was introduced into biodegradable methoxy poly(ethylene glycol)-thioketal-poly(ε-caprolactone)mPEG-TK-PCL micelles as a linker, which was designed to speed up the drug release and thus enhance the therapeutic efficacy. The micelle showed a high drug loading content of 12.8% and excellent stability under physiological conditions because of the evocation of π-π stacking and hydrophobic interactions with the anticancer drug doxorubicin (DOX). The polymeric micelle presented a better drug carrier capacity and higher in vitro anticancer efficacy towards cancer cells. The in vivo study showed that DOX-loaded mPEG-TK-PCL micelles displayed lower toxicity towards normal cells and remarkably enhanced antitumor efficacy. This research provides a way to design potential drug carriers for efficient cancer chemotherapy.

Correction for ‘Iron-catalyzed para-selective C–H silylation of benzamide derivatives with chlorosilanes’ by Pei Liu et al., Org. Chem. Front., 2021, DOI: 10.1039/d1qo00243k.

Upconversion nanoparticles/semiconductor nanocomposites have received intense interest in the past two decades. In this work, we demonstrated a facile electrospinning technique and a hydrothermal-assisted crystallization process to fabricate upconversion nanoparticles (UCNPs)/CdS/TiO2 nanofibers successfully. Polyvinylpyrrolidone (PVP, Mw ≈ 1 300 000) has been selected as the polymer matrix and tetrabutyl titanate (TBT, 99.0%) was used as the titanium source. The morphologies and phase of the as-prepared samples have been studied using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Experimental results revealed that the polymer matrix (PVP) can be dissolved and removed completely under hydrothermal conditions. In addition, the crystalline phase of TiO2 was also achieved under hydrothermal conditions. The as-prepared composite nanofibers are hundreds of micrometers in length and 650 nm in diameter and show weak upconversion fluorescence under the excitation of near-infrared light (980 nm), indicating the high energy transfer efficiency between upconversion nanoparticles and semiconductors. As expected, the UCNPs/CdS/TiO2 nanofibers may have enhanced photocatalytic performance as they make full use of solar energy using UCNPs as nanotransducers for infrared (IR) light.

A facile strategy was put forward to fabricate highly luminescent metal–organic frameworks (MOFs) with tunable and white-light emission by incorporating lanthanide cations (Ln3+) into the channels of MIL-121 (Al(OH)(H2btec)·H2O) whose uncoordinated carboxyl groups can act as post-synthetic modification sites. The intense luminescence of Ln3+ doped MIL-121 indicates that the framework with rigid, permanently porous structure and non-coordinated carboxyl can serve as both a scaffold and an antenna for hosting and sensitizing the luminescence of Ln3+ cations. Moreover, a fine-tuning of the emitted color luminescence can be easily achieved by simply modulating the doping ratio or adjusting the excitation wavelength. Notably, the red–green–blue-based white light emitting Ln-MOFs can be realized by simultaneously doping Eu3+ and Tb3+ into the host framework. In addition, because of the excellent luminescence and the structural stability of Ln3+ functionalized MIL-121 (Ln3+@MIL-121) in water or solvents, the Eu3+@MIL-121 was developed as a luminescent probe for sensing of anions in aqueous solutions and small organic molecules. Luminescent studies reveal that Eu3+@MIL-121 not only display a high-sensitivity sensing function with respect to fluoride and dichromate ions but also exhibit significant solvent-dependent luminescent response to small-molecule pollutants, such as chloroform and acetone.

Two novel metal–organic frameworks, formulated as [Ni3(qptc)2(H2O)3]·3.5H2O·3Me2NH (1) and [Co3(qptc)2(H2O)4]·5H2O (2) (H4qptc = 1,1′:4′,1′′:4′′,1′′′-quaterphenyl-2,4,2′′′,4′′′-tetracarboxylic acid), have been hydrothermally constructed based on a rigid aromatic multicarboxylate ligand. The single-crystal X-ray diffraction analysis shows that complex 1 crystallizes in the triclinic crystal system with space group P and possesses a 4,8-connected 3D open framework including trinuclear nickel Ni3 SBUs, which belongs to an scu topology with the point symbols (416·612) and (44·62). Complex 2 belongs to the monoclinic crystal system with space group C2/c and exhibits a 3D framework containing Co3 SBUs, which is a flu topology with the point symbols (412·612·84) and (46). Furthermore, the variable-temperature magnetic susceptibilities of complexes 1 and 2 have been investigated. Both complexes show weak ferromagnetic coupling between metal ions estimated by using a linear trinuclear model for 1 in the range of 2–300 K and the PHI program for 2 in the range of 20–300 K taking the orbital contribution into consideration.

A new class of lanthanide luminescent MOFs was constructed by encapsulating Ln3+ into the pores of MIL-121 (Ln3+@MIL-121). Ag+ was found to be able to greatly enhance the weak visible or NIR luminescence of Ln3+@MIL-121 since it can induce more efficient intramolecular energy transfer from the ligand to Ln3+ in Ag–Ln co-doped MOFs.

Nine 3D isomorphic bimetallic coordination polymers with different alkali metals (Na, K, and Rb) and halides (Cl, Br, and I) have demonstrated that the 4,5-dicyanoimidazole ligand is a good template in the assembly of bimetallic–organic networks. This provides an excellent template for the investigation of ion exchange and single-crystal to single-crystal (SCSC) transformation. The series of coordination polymers shows an unprecedented (3,4,6)-connected (5·72)6(52·6·73)6(56·66·73) net with a high topology density.

Hydrothermal reactions of Mn(II)/Co(II) salts and H4qptc in the presence of corresponding auxiliary N-donor ligands produced four novel complexes, {[Mn2(qptc)(4,4′-bibp)(H2O)4]·2H2O}n (1), [Mn2(qptc)(1,4-bib)(H2O)8]n (2), [Co2(qptc)(4,4′-bimbp)(H2O)2]n (3) and {[Co2(qptc)(1,3-dpp)(H2O)3]·H2O}n (4) (H4qptc = 1,1′:4′,1′′:4′′,1′′′-quaterphenyl-2,4,2′′′,4′′′-tetracarboxylic acid, 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl, 1,4-bib = 1,4-bis(1-imidazoly)benzene, 4,4′-bimbp = 4,4′-bis(imidazol-1-ylmethyl)biphenyl, 1,3-dpp = 1,3-di(4-pyridyl)propane). Single-crystal X-ray diffraction analysis showed that these complexes have different structures, including a 1D chain (2), a 2D layered structure (3), and a 3D network (1 and 4), depending on reaction conditions. Complex 1 is a 4,6-connected porous 3D framework with the point symbol (44·62)(44·610·8), which is composed of infinite 2D networks pillared by a 4,4′-bibp bridging ligand. 2 is a 1D zigzag chain, and the adjacent chains extend to a 3D supramolecular structure via non-covalent interactions involving contributions from carboxyl–water clusters. 3 is a 2D layer framework with an unprecedented topology, which are packed into a 3D supramolecular architecture by π⋯π and C–H⋯π interactions. 4 is a 4,6-connected 3D network with a Schlafli symbol of (3·4·54)(32·4·55·66·7). Furthermore, the magnetic susceptibility of complexes 1–4 have been investigated. 1 and 4 display weak antiferromagnetic behavior, 2 shows weak ferromagnetic interactions, and 3 exhibits different magnetic properties depending on temperature.

A lanthanide-functionalized MOF with extremely high water tolerance was developed as a fluorescent probe for hippuric acid (HA) in urine which is considered as the biological indicators of toluene exposure. For the first time, the urinary HA was detected by fluorescence spectrometry based on a recyclable Ln-MOF sensor.

Solvothermal reactions of LnCl3·6H2O (Ln = Eu, Tb, Sm and Dy) with 2-aminoterephthalic acid obtain four isostructural lanthanide(III)–organic frameworks. The structure has the topology of a gadolinium 2-aminoterephthalic acid (MOF-LIC-1). The as-obtained samples were characterized by X-ray diffraction, FT-IR, TGA and luminescence spectroscopy. They all belong to the luminescence materials system with broad band excitation, which could extend to the visible-light region. The selected ligand could effectively sensitize the luminescence of Eu3+, Tb3+ and Sm3+, particularly the Eu3+ ions; thus, leading to the characteristic luminescence of Ln3+. More significantly, the white-light emission may be realized by a single-component Sm(III) framework. Furthermore, Eu-MOF was selected as a representative sample to examine the potential of the material for the sensing of metal ions. It showed highly selective and sensitive luminescence sensing for Al3+ ions. In addition, the luminescence color change can be easily distinguished with the naked eye under UV-light irradiation.

A series of novel polymer–lanthanide–zeolite A hybrid films have been synthesized by polymerization of ethyl methacrylate (EMA) and 4-vinylpyridine (4VP) containing surface modified zeolite A, inside the channels of which lanthanide complexes are incorporated. The surface modification was conducted by first functionalizing zeolite A with a multi-functional linker and then covalently grafting lanthanide ions which coordinate to both the molecular linker and the polymer chain. The SEM images suggest that lanthanide-based zeolite A particles are evenly dispersed in the polymer matrices, leading to a certain transparency of the thin films. The luminescence properties of the resulting materials were characterized in detail and the results reveal that all the materials exhibit intense emission lines upon UV-light irradiation. Various emitting colors of the zeolite A–polymer materials can be obtained by simply changing the lanthanide complexes inside and outside the channels of zeolite A. Furthermore, the white light emission from the tricolor luminous materials can be easily obtained by adjusting the different concentrations of the doped ions and the excitation wavelength.

A 3D microporous compound Al(OH) (H2btec)·H2O (MIL-121) containing uncoordinated carbonyl groups is selected as a parent metal–organic framework (MOF). Moreover, because the uncoordinated carbonyl groups in the channels could act as a postsynthetic modification sites, a robust luminescent lanthanide-based MOF can be constructed by encapsulating Eu3+ cations into the pores of MIL-121. The intense luminescence of Eu3+ incorporated MIL-121 products demonstrates that the framework with rigid, permanently porous structure and non-coordinated carboxyl group is an efficient scaffold for hosting and sensitizing Eu3+ cations. More significantly, the robust Eu3+@MIL-121 shows excellent selectivity, fast detection time (

Eight host-guest assemblies of zeolite A (ZA) and their thin films have been synthesized. The assembly of zeolite A was prepared by first embedding lanthanide complexes (Eu(TTA)n or Tb(TAA)n) into the cages of zeolite A and then grafting lanthanide complexes (Eu(L) or Tb(L), L = bipy or phen) onto the surface of functionalized zeolite A via 3-(methacryloyloxy)propyltrimethoxysilane (γ-MPS). The obtained organic-inorganic hybrid materials were investigated by means of XRD, FT-IR, SEM and luminescence spectroscopy. Firstly, the dependence of the crystal stability of zeolite A as the host of lanthanide complexes on the level of ion exchange was studied by XRD. The results indicated the degradation and partial collapse of zeolite A framework occurred upon doping with high amounts of lanthanide complexes into its channels. The integrity of zeolite A's framework was well maintained after fabrication through careful control of the ion-exchange extent. Secondly, the thin films of zeolite A assemblies obtained this way have the properties of homogeneous dense packing and a high degree of coverage of the crystals on the ITO glass, as shown in SEM images. Thirdly, the luminescence behavior of all the materials were investigated in detail. Among them, four white light-emitting materials from a three-component system that comprises a blue-emitting zeolite A matrix, a red-emitting europium complex and a green-emitting terbium complex were obtained.

The novel coordination polymer [Co4(2,2′-bipy)4(H2O)2(btec)2]n (btec = 1,2,4,5-benzenetetracarboxylate), 1, has been hydrothermally synthesized. X-Ray diffraction experiments reveal that 1 exhibits an interesting two-dimensional (2D) chiral undulated (6,4)-network, which represents the first example of a 2D chiral coordination polymer containing two kinds of organic ligands. The value of the Flack parameter, x = 0.52(2), shows that the crystal of 1 is an inversion twin containing approximately 50% of the right-handed and 50% of the left-handed crystal structure and the whole compound is a racemate. Variable temperature magnetic susceptibility indicates that antiferromagnetic interactions exist between metallic Co(II) centers in 1.

We demonstrate an efficient synthesis of novel layered double hydroxide mesoporous silica core-shell nanostructures (LDH@mSiO(2)) that have a hexagonal MgAl-LDH nanoplate core and an ordered mesoporous silica shell with perpendicularly oriented channels via a surfactant-templating method. Transmission electron microscopy, X-ray diffraction and N(2) sorption analyses confirmed that the obtained nanostructures have uniform accessible mesopores (∼2.2 nm), high surface area (∼430 m(2) g(-1)), and large pore volume (∼0.22 cm(3) g(-1)). Investigations of drug release and bio-imaging showed that this material has a slow release effect of ibuprofen and good biocompatibility. This work provides an economical approach to fabricate LDH@mSiO(2) core-shell nanostructures, which may have great potential in broad drug delivery and hyperthermia therapy applications.