A Supramolecular Catalyst Self-Assembled From Polyoxometalates and Cationic Pillar[5]arenes for the Room Temperature Oxidation of Aldehydes

Oxidizing aldehydes to generate carboxylic acids is a crucial reaction in nature and in chemical industry. The aldehyde oxidation, an easily achieved process in liver cells, is inert toward autoxidation in industrial production and difficultly achieved under enzymatic condition (in water, at pH 7, at room temperature). Herein, we prepared a supramolecular catalyst which are nanospheres assembled in aqueous media by chromium centered Anderson polyoxometalates Na3[CrMo6O18(OH)3] (namely, CrMo6) and cationic pillar[5]arenes (namely, P5A) with 10 positive charges which can be used as the phase transfer catalysts (PTCs). This supramolecular catalyst was exploited on aldehydes oxidation under enzymatic condition with relatively good conversion. Through DLS monitoring, the diameters of nanospheres were variable while changing the charge ratios of the ionic complexes (P5A-CrMo6), and it is probably because of the closer charge ratios causing the more compact assemblies. Also, the nano-morphologies were monitored by TEM and SEM, and the nanostructures were characterized by zeta potential, the X-ray energy-dispersive spectroscopy (EDS), elemental analysis

Unprecedented halide‐ion binding and catalytic activity of nanoscale anionic metal oxide clusters

One halide ion (X−) can bind on the surface of nanoscale Anderson‐type polyoxometalate (POMs) clusters [(n‐C4H9)4N]3{AlMo6O18(OH)3[(OCH2)3CCH3]}, and form stable complexes in solution with binding constant K=1.53×103. Single‐crystal structural analysis showed that this binding behavior occurs through multiple hydrogen bonding between X− and three hydroxy groups on the uncapped side of the cluster. This supramolecular interaction in the cluster systems means that their catalytic activities, evaluated from the oxidation of alcohols to aldehydes, can be switched upon the introduction of halide ions and water molecules. The halide ions work as inhibitors by blocking the active sites of the clusters while they can be re‐activated by the addition of water

Polyoxometalatocrown ether: A new type of metallacrown ether based on polyoxometalate

Using chain-like polyethers consisting of two terminal –NH2 groups and (TBA)4[α-Mo8O26] as starting materials, two polyoxometalatocrown ethers were prepared by a cyclization reaction through the formation of Mo≡N triple bonds: (TBA)2[Mo6O17N(o-C6H4OCH2(CH2OCH2)nCH2OC6H4-o)N] (compounds 1, n = 1; 2, n = 2). As confirmed by single-crystal X-ray diffraction and infrared (IR) studies, the polyoxometalatocrown ether 2 can capture primary ammonium cations in solid state

Supramolecular self-assembly of polyoxometalates and cyclodextrin: Progress and perspectives

In this study, we present a comprehensive overview of supramolecular self-assemblies comprising cyclodextrins (CDs) and polyoxometalates (POMs). We summarize the recent advancements in supramolecular POM–CD systems, including their structures, functions, and applications. Subsequently, we focus on the self-assembly behavior of CDs and POMs, encompassing the formation of inclusion complexes, host–guest interactions, and the development of hybrid materials. In addition, we discuss the remarks on future outlooks and hope that this review will serve as a valuable reference for researchers engaged in the fields of supramolecular/POM chemistry, materials science, and nanotechnology

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Recent Advances of Anderson-Type Polyoxometalates as Catalysts Largely for Oxidative Transformations of Organic Molecules

Anderson-type ([XM6O24]n−) polyoxometalates (POMs) are a class of polymetallic-oxygen cluster inorganic compounds with special structures and properties. They have been paid extensive attention by researchers now, due to their chemical modification and designability, which have been widely applied in the fields of materials, catalysis and medicine. In contemporary years, the application of Anderson-type POMs in catalytic organic oxidation reaction has gradually shown great significance for the research of green catalytic process. In this paper, we investigate the application of Anderson-type POMs in organic synthesis reaction, and these works are summarized according to the different structure of POMs. This will provide a new strategy for further investigation of the catalytic application of Anderson-type POMs and the study of green catalysis

Additive-Mediated Selective Oxidation of Alcohols to Esters via Synergistic Effect Using Single Cation Cobalt Catalyst Stabilized with Inorganic Ligand

The direct catalytic oxidation of alcohols to esters is very appealing, but the economical-friendly catalysis systems are not yet well established. Herein, we show that a pure inorganic ligand-supported single-atomic cobalt compound, (NH4)3[CoMo6O18(OH)6] (simplified as CoMo6), could be used as a heterogeneous catalyst and effectively promote this type of reaction in the presence of 30% H2O2 using KCl as an additive. The oxidative cross-esterification of various alcohols (aromatic and aliphatic) could be achieved under mild conditions in nearly all cases, affording the corresponding esters in high yields, including several drug molecules and natural products. Detailed studies have revealed that chloride ion is able to bind to the CoMo6 to form a supramolecular dimer 2(CoMo6∙Cl), which can effectively catalyze the reaction via a synergistic effect from chloride ion and CoMo6. Mechanism studies and control reactions demonstrate that the esterification proceeds via the key oxidative immediate of aldehydes