Porous and Robust Lanthanide Metal-Organoboron Frameworks as Water Tolerant Lewis Acid Catalysts

Porous and robust 12-connected metal–organic frameworks (MOFs) were constructed by linking tetranuclear lanthanide (Ln) carbonate clusters with organoboron-derived tricarboxylate bridging ligands. The high-connectivity Ln-MOFs feature remarkable thermal and hydrolytic stability and a large number of isolated Lewis acid B­(III) and Ln­(III) sites on the pore surfaces. The Nd-MOF assisted with sodium dodecylsulfate was found to be highly effective, recyclable, and reusable heterogeneous catalyst for the carbonyl allylation reaction, the Diels–Alder reaction, and the Strecker-type reaction in water. The transformations were cocatalyzed by Nd­(III) and B­(III) Lewis acids, with activities much higher than those of the individual organoboron and lanthanide counterparts and their mixture. This work highlights the potential of generating highly efficient water-tolerant solid catalysts via heterogenization of different weak and/or mild Lewis acids in confined spaces of robust MOFs

Homochiral Silver-Based Coordination Polymers Exhibiting Temperature-Dependent Photoluminescence Behavior

Homochiral coordination polymers based on zigzag or helical polymers are assembled from a semiflexible fluorescent bipyridyl ligand and linear coordinated Ag^I ions; they exhibit unusual temperature-dependent photoluminescence behavior, including multistep changes in energy and intensity upon cooling

Homochiral Silver-Based Coordination Polymers Exhibiting Temperature-Dependent Photoluminescence Behavior

Homochiral coordination polymers based on zigzag or helical polymers are assembled from a semiflexible fluorescent bipyridyl ligand and linear coordinated Ag^I ions; they exhibit unusual temperature-dependent photoluminescence behavior, including multistep changes in energy and intensity upon cooling

Porous and Robust Lanthanide Metal-Organoboron Frameworks as Water Tolerant Lewis Acid Catalysts

Porous and robust 12-connected metal–organic frameworks (MOFs) were constructed by linking tetranuclear lanthanide (Ln) carbonate clusters with organoboron-derived tricarboxylate bridging ligands. The high-connectivity Ln-MOFs feature remarkable thermal and hydrolytic stability and a large number of isolated Lewis acid B­(III) and Ln­(III) sites on the pore surfaces. The Nd-MOF assisted with sodium dodecylsulfate was found to be highly effective, recyclable, and reusable heterogeneous catalyst for the carbonyl allylation reaction, the Diels–Alder reaction, and the Strecker-type reaction in water. The transformations were cocatalyzed by Nd­(III) and B­(III) Lewis acids, with activities much higher than those of the individual organoboron and lanthanide counterparts and their mixture. This work highlights the potential of generating highly efficient water-tolerant solid catalysts via heterogenization of different weak and/or mild Lewis acids in confined spaces of robust MOFs

A Homochiral Metal–Organic Framework as an Effective Asymmetric Catalyst for Cyanohydrin Synthesis

A homochiral metal–organic framework (MOF) of an enantiopure 2,2′-dihydroxy-1,1′-biphenyl ligand was constructed. After exchanging one proton of the dihydroxyl group for Li­(I) ions, the framework is shown to be a highly efficient and recyclable heterogeneous catalyst for asymmetric cyanation of aldehydes with up to >99% ee. Compared with the homogeneous counterpart, the MOF catalyst exhibits significantly enhanced catalytic activity and enantioselectivity, especially at a low catalyst/substrate ratio, due to that the rigid framework could stabilize the catalytically active monolithium salt of biphenol against its free transformation to catalytically inactive and/or less active assemblies in reactions. The synthetic utility of the cyanation was demonstrated in the synthesis of (<i>S</i>)-bufuralol (a nonselective β-adrenoceptor blocking agent) with 98% ee

Chiral Metal–Organic Framework Decorated with TEMPO Radicals for Sequential Oxidation/Asymmetric Cyanation Catalysis

A chiral porous metal–organic framework (MOF) decorated with radicals has been successfully constructed by cocrystallizing achiral (2,2,6,6-tetramethylpiperidin-1-yl)­oxyl (TEMPO)-substituted tricarboxylate and enantiopure VO­(salen)-derived dipyridine ligands. The chiral MOF can function as an efficient heterogeneous catalyst for the sequential alcohol oxidation/asymmetric cyanation of aldehyde reactions with enhanced activity and enantioselectivity compared to the homogeneous counterpart

A Novel and Versatile Strategy to Prepare Metal–Organic Molecular Precursor Solutions and Its Application in Cu(In,Ga)(S,Se)₂ Solar Cells

A novel and versatile metal–organic molecular precursor-based solution approach and the fabrication of high efficiency Cu­(In,Ga)­(S,Se)₂ solar cells are presented. Many types of metal oxides, hydroxides, and acetylacetonates (acac), such as Cu₂O, ZnO, SnO, Sb₂O₃, MnO, PbO, In­(OH)₃, Cd­(OH)₂, Ga­(acac)₃, and so forth, can be easily dissolved in butyldithiocarbamic acid, forming thermally degradable metal–organic molecular precursor solutions. By developing a simple and green ethanol solution-processed route and tuning the chemical composition of the Cu­(In,Ga)­(S,Se)₂ thin film, as-fabricated solar cells exhibit an average power conversion efficiency up to 8.8%

Identification of a Plasma Four-microRNA Panel as Potential Noninvasive Biomarker for Osteosarcoma

<div><p>Background</p><p>Circulating microRNAs (miRNAs) are emerging as promising biomarkers for human cancer. Osteosarcoma is the most common human primary malignant bone tumor in children and young adults. The objective of this study was to investigate whether circulating miRNAs in plasma could be a useful biomarker for detecting osteosarcoma and monitoring tumor removal dynamics.</p><p>Methods</p><p>Plasma samples were obtained from 90 patients before surgery, 50 patients after one month of surgery, and 90 healthy individuals. The study was divided into three steps: First, initial screening of the profiles of circulating miRNAs in pooled plasma samples from healthy controls and pre-operative osteosarcoma patients using a TaqMan low density array (TLDA). Second, evaluation of miRNA concentration in individual plasma samples from 90 pre-operative osteosarcoma patients and 90 healthy controls by a quantitative real time PCR (qRT-PCR) assay. Third, evaluation of miRNA concentration in paired plasma samples from 50 pre- and post-operative osteosarcoma patients by qRT-PCR assay.</p><p>Results</p><p>Four plasma miRNAs including miR-195-5p, miR-199a-3p, miR-320a, and miR-374a-5p were significantly increased in the osteosarcoma patients. Receiver operating characteristics curve analysis of the combined populations demonstrated that the four-miRNA signature could discriminate cases from controls with an area under the curve of 0.9608 (95% CI 0.9307-0.9912). These 4 miRNAs were markedly decreased in the plasma after operation. In addition, circulating miR-195-5p and miR-199a-3p were correlated with metastasis status, while miR-199a-3p and miR-320a were correlated with histological subtype.</p><p>Conclusions</p><p>Our data suggest that altered levels of circulating miRNAs might have great potential to serve as novel, non-invasive biomarkers for osteosarcoma.</p></div

Analysis of plasma miRNA expression profiles by TLDA.

<p>Correlation and scatter plot analysis of miRNAs expression levels in pooled plasma samples from healthy controls and pre-operative osteosarcoma patients (each pooled from 10 individuals).</p

Chiral 3D Covalent Organic Frameworks for High Performance Liquid Chromatographic Enantioseparation

In spite of their great promise for enantioselective processes due to the rich host–guest chemistry, it remains a challenge to construct covalent organic frameworks (COFs) with chiral three-dimensional (3D) structures. Here we report bottom-up synthesis of the first example of 3D chiral COFs by imine condensation of an enantiopure 2-fold symmetric TADDOL-derived tetraaldehyde with a tetrahedral tetra­(4-anilyl)­methane. After postsynthetic oxidation of imine linkages, the framework is transformed into an amide-linked COF with retention of crystallinity and permanent porosity as well as enhanced chemical stability. The resultant isostructural COFs feature a 4-fold interpenetrated diamondoid open framework with tubular channels decorated with chiral dihydroxy auxiliaries. Both COFs can be used as chiral stationary phases for high performance liquid chromatography to enantioseparate racemic alcohols, and the oxidized COF shows superior separation performance compared to the pristine framework