Bifunctional and recyclable polyesters by chemoselective ring-opening polymerization of a δ-lactone derived from CO and butadiene.

When aiming at the direct use of CO for the preparation of advanced/value-added materials, the synthesis of CO/olefin copolymers is very appealing but challenging. The δ-lactone 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVP), synthesized by telomerization of CO with 1,3-butadiene, is a promising monomer. However, its chemoselective ring-opening polymerization (ROP) is hampered by unfavorable thermodynamics and the competitive polymerization of highly reactive C=C double bonds under usual conditions.

Photodimerization-Triggered Photopolymerization of Triene Coordination Polymers Enables Macroscopic Photomechanical Movements.

Controlling the packing of olefinic molecules in crystals is essential for triggering solid-state [2 + 2] photocycloaddition reactions and the synthesis of photocontrolled smart materials. Herein, we report the stepwise photodimerization-triggered photopolymerization of two triene coordination polymers (CPs), {[Zn(2-BBA)(tpeb)]·0.5CHCN} (, 2-HBBA = 2-bromobenzoic acid, tpeb = 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene) and {[Zn(3-BBA)(tpeb)]·CHCN)} (, 3-HBBA = 3-bromobenzoic acid).

Tandem Protocol for Diversified Deuteration of Secondary Aliphatic Amines under Mild Conditions.

Deuteration of amine compounds has been widely of concern because of its practical role in organic reaction mechanisms and drug research; however, only limited deuteration label methods are accessible with DO as a deuterium source. Herein, we propose a convenient deuteration protocol, including preparing D by the AlGa activation method, using PtRu nanowires as catalysts, and utilizing the elementary step in the couple reaction involving an imine unit, to realize the rapid preparation of a secondary amine with a diversified deuteration label. The self-coupling between nitriles not only provides a symmetric secondary amine with four α-D atoms but also produces high-valued ND in an atomic-economic way.

Liquid Gallium-Assisted Pyrolysis of MOF Affording CNT Non-Hollow Frameworks in High Yields for High-Performance Sodium-Ion Battery Anode.

Carbon materials have great potential for applications in energy, biology, and environment due to their excellent chemical and physical properties. Their preparation by carbonization methods encounters limitations and the carbon loss during pyrolysis in the form of gaseous molecules results in low yield of carbon materials. Herein a low-energy (600 °C) and high-yield (82 wt.

Zwitterionic Thiolate-Protected Ag(0/I) and Ag(I) Clusters: Assembly, Structural Characterization, and Antibacterial Activity.

Zwitterionic thiolate ligands have the potential to introduce novel assembly modes and functions for noble metal clusters. However, their utilization in the synthesis of silver clusters remains understudied, particularly for the clusters containing reductive Ag(0) species. In this article, we report the first synthesis of a mixed-valence silver(0/I) cluster protected by zwitterionic Tab as thiolate ligands (Tab = 4-(trimethylammonio)benzenethiolate), denoted as [Ag(Tab)](PF)·16CHOH·6EtO (·16CHOH·6EtO), alongside an Ag(I) cluster [Ag(Tab)(PhCOO)(MeCN)(HO)](PF)·11MeCN (·11MeCN).

Interfacial Electronic Interactions Between Ultrathin NiFe-MOF Nanosheets and Ir Nanoparticles Heterojunctions Leading to Efficient Overall Water Splitting.

Creating specific noble metal/metal-organic framework (MOF) heterojunction nanostructures represents an effective strategy to promote water electrolysis but remains rather challenging. Herein, a heterojunction electrocatalyst is developed by growing Ir nanoparticles on ultrathin NiFe-MOF nanosheets supported by nickel foam (NF) via a readily accessible solvothermal approach and subsequent redox strategy. Because of the electronic interactions between Ir nanoparticles and NiFe-MOF nanosheets, the optimized Ir@NiFe-MOF/NF catalyst exhibits exceptional bifunctional performance for the hydrogen evolution reaction (HER) (η = 15 mV, η denotes the overpotential) and oxygen evolution reaction (OER) (η = 213 mV) in 1.

New Pyridine Dicarbene Pincer Ligands with Ring Expanded NHCs and their Nickel and Chromium Complexes.

The pincer complexes [NiBr(CNC)]Br (4), [CrBr(CNC)] (5 a) and [CrBrCl(CNC)] (5 b), where CNC=3,3'-(pyridine-2,6-diyl)bis(1-mesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene), were obtained from the novel ligand CNC, generated in situ from the precursor (CHNCH)Br and [NiBr(PPh)] or from [Cr{N(SiMe)}(THF)] and (CHNCH)Br by aminolysis, respectively. The tetrahedrally distorted square planar (τ≅0.30) geometry and the singlet ground state of Ni in 4 were attributed to steric constraints of the CNC backbone.

Construction of olefinic coordination polymer single crystal platforms: precise organic synthesis, exploration of reaction mechanisms and beyond.

Olefin [2+2] photocycloaddition reactions based on coordination-bond templates provide numerous advantages for the selective synthesis of cyclobutane compounds. This review outlines the recent advances in the design and construction of single crystal platforms of olefinic coordination polymers for precise organic synthesis, exploration of reaction mechanisms, and possible developments as comprehensively as possible. Numerous examples are presented to illustrate how the arrangements of the olefin pairs influence the solid-state photoreactivity and examine the types of cyclobutane products.

Daily fluctuations in blood glucose with normal aging are inversely related to hippocampal synaptic mitochondrial proteins.

Defective brain glucose utilization is a hallmark of Alzheimer's disease (AD) while Type II diabetes and elevated blood glucose escalate the risk for AD in later life. Isolating contributions of normal aging from coincident metabolic or brain diseases could lead to refined approaches to manage specific health risks and optimize treatments targeted to susceptible older individuals. We evaluated metabolic, neuroendocrine, and neurobiological differences between young adult (6 months) and aged (24 months) male rats.

In situ observation of a stepwise [2 + 2] photocycloaddition process using fluorescence spectroscopy.

Using highly sensitive and selective in situ techniques to investigate the dynamics of intermediates formation is key to better understand reaction mechanisms. However, investigating the early stages of solid-state reactions/transformations is still challenging. Here we introduce in situ fluorescence spectroscopy to observe the evolution of intermediates during a two-step [2 + 2] photocycloaddition process in a coordination polymer platform.

Self-Assembly of Cluster-Mediated 3D Catenanes with Size-Specific Recognition Behavior.

Although interlocked three-dimensional molecules display unique properties associated with their spatial structures, their synthesis and study of their host-guest properties remain challenging. We report the formation of a novel [2]catenane, [EtN]@[(Tp*WSCuCl)(-bpype)](OTf) ([EtN][](OTf)), by self-assembly of the cluster node [Tp*WSCuCl] and the organic linker ()-1,2-diphenyl-1,2-bis(4-(pyridin-4-yl)phenyl)ethene (-bpype). Single-crystal X-ray and NMR analyses established that [] is formed by the interpenetration of two cluster-organic cages.

Gold complexes with remote-substituted amino N-heterocyclic carbenes.

The 4-RN-1,3-Ar-imidazolium salt, R = iPr, Bu, Ar = Mes, Dipp, Mes = mesityl, Dipp = 2,6-bis-diisopropyl-phenyl was metalated by Au at the C2-, C5- and 4-RN positions depending on the reactants and conditions employed; a rare direct rearrangement of a Au aminide to an abnormal imidazol-5-ylidene Au complex was also observed and based on a DFT study it may involve TfO facilitated H transfer.

Photopolymerization-Driven Macroscopic Mechanical Motions of a Composite Film Containing a Vinyl Coordination Polymer.

We report a unique vinyl coordination polymer (CP), [Zn(4-Fb) (tkpvb)] (1, 4-HFb=4-fluorobenzoic acid, tkpvb=1,2,4,5-tetrakis(4-pyridylvinyl)benzene) that undergoes a rare photopolymerization reaction to form a two-dimensional CP integrated with a one-dimensional linear organic polymer. Upon light irradiation at different wavelengths, 1 exhibits an unprecedented phenomenon of photoinduced nonlinear lattice expansion. 1 can be uniformly dispersed in polyvinyl alcohol (PVA) to form the composite film of 1-PVA.

Carbonylmetallates as Versatile 2-, 4- or 6-Electron Donor Metalloligands in Transition-Metal Complexes and Clusters: A Global Approach.

Carbonylmetallates [m] , such as [MoCp(CO) ] , [Mn(CO) ] , [Co(CO) ] , have long been successfully used in the preparation of hundreds of metal-metal bonded carbonyl complexes and clusters, in particular of the heterometallic type. We focus here on situations where [m] can be viewed as a terminal, doubly or even triply bridging metalloligand, developing metal-metal interactions with one, two or three metal centers M, respectively. With metals M from the Groups 10-12, it is not straightforward or even impossible to rationalize the structure of the resulting clusters by applying the well-known Wade-Mingos rules.

Surface deposition of 2D covalent organic frameworks for minimizing nanocatalyst sintering during hydrogenation.

A strategy of depositing 2D COFs on heterogeneous catalysts was reported for the first time to suppress the agglomeration and sintering of the supported metal nanoparticles during hydrogenation processes. The COF-decorated nanocatalysts exhibited excellent stability in various hydrogenation reactions including the reduction of dimethyl oxalate (DMO), furfural, and other chemicals.

Dual-ligand and hard-soft-acid-base strategies to optimize metal-organic framework nanocrystals for stable electrochemical cycling performance.

Most metal-organic frameworks (MOFs) hardly maintain their physical and chemical properties after exposure to acidic, neutral, or alkaline aqueous solutions, resulting in insufficient stability, therefore limiting their applications. Thus, the design and synthesis of stable size/morphology-controlled MOF nanocrystals is critical but challenging. In this study, dual-ligand and hard-soft-acid-base strategies were used to fabricate a variety of 3D pillared-layer [Ni(thiophene-2,5-dicarboxylate)(4,4-bipyridine)] MOF nanocrystals (1D nanofibers, 2D nanosheets and 3D aggregates) with controllable morphology by varying the concentration of 4,4-bipyridine and thus controlling the crystal growth direction.

A cavity-shaped -chelating P,N ligand for highly selective nickel-catalysed ethylene dimerisation.

The presence of a permethylated α-cyclodextrin (α-CD) cavity in a chelating P,N ligand promotes exclusive formation of 1 : 1 ligand/metal complexes. In MX complexes, one of the two halido ligands is forced to reside inside the CD hollow while the second one is pointing outside. Unlike its cavity-free analogue, a Ni(II) complex of the CD ligand is a highly selective precatalyst for ethylene dimerisation (96% C selectivity with up to 95% of 1-butene within the C fraction).

Electrochemical activation-induced surface-reconstruction of NiO microbelt superstructure of core-shell nanoparticles for superior durability electrocatalysis.

The tailoring of intrinsic electronic structures and extrinsic hierarchical morphologies is widely recognized as a promising strategy to enhance the oxygen evolution reaction (OER) performance of electrocatalysts. It is generally accepted that the surface of the transition metal-based electrocatalyst exposed to the alkaline electrolyte is highly oxidized and reconstructed, forming an amorphous layer during the electrochemical process. This amorphous active phase is favorable for OER due to its abundant dangling bonds, vacancies and defects, which is tricky to be rationally prepared by conventional methods.

Controllable multiple-step configuration transformations in a thermal/photoinduced reaction.

Solid-state photochemical reactions of olefinic compounds have been demonstrated to represent powerful access to organic cyclic molecules with specific configurations. However, the precise control of the stereochemistry in these reactions remains challenging owing to complex and fleeting configuration transformations. Herein, we report a unique approach to control the regiospecific configurations of C = C groups and the intermediates by varying temperatures in multiple-step thermal/photoinduced reactions, thus successfully realizing reversible ring closing/opening changes using a single-crystal coordination polymer platform.

Experimental and Theoretical Study of Ni - and Pd -Promoted Double Geminal C(sp )-H Bond Activation Providing Facile Access to NHC Pincer Complexes: Isolated Intermediates and Mechanism.

We report the first examples of metal-promoted double geminal activation of C(sp )-H bonds of the N-CH -N moiety in an imidazole-type heterocycle, leading to nickel and palladium N-heterocyclic carbene complexes under mild conditions. Reaction of the new electron-rich diphosphine 1,3-bis((di-tert-butylphosphaneyl)methyl)-2,3-dihydro-1H-benzo[d]imidazole (1) with [PdCl (cod)] occurred in a stepwise fashion, first by single C-H bond activation yielding the alkyl pincer complex [PdCl(PC P)] (3) with two trans phosphane donors and a covalent Pd-C bond. Activation of the C-H bond of the resulting α-methine C H-M group occurred subsequently when 3 was treated with HCl to yield the NHC pincer complex [PdCl(PC P)]Cl (2).

Engineering the Electronic Structures of Metal-Organic Framework Nanosheets via Synergistic Doping of Metal Ions and Counteranions for Efficient Water Oxidation.

Metal-organic framework (MOF) nanosheets with attractive chemical and structural properties have been considered as prominent oxygen evolution reaction (OER) electrocatalysts, while the insufficient exposed active sites and low electrical conductivity of MOFs limit their electrocatalytic activity and further industrial applications. Herein, a unique strategy to remarkably boost electrocatalytic OER activity of one Ni-based MOF is developed by the simultaneous incorporation of Fe ions and BF anions within its layer structure. The optimized electrocatalyst NiFe-MOF-BF-0.

Flexible Vertex Engineers the Controlled Assembly of Distorted Supramolecular Tetrahedral and Octahedral Cages.

Designing and building unique cage assemblies attract increasing interest from supramolecular chemists but remain synthetically challenging. Herein, we propose the use of a flexible vertex with adjustable angles to selectively form highly distorted tetrahedral and octahedral cages, for the first time, in which the flexible vertex forms from the synergistic effect of coordination and covalent interactions. The inherent interligand angle of the vertex can be modulated by guest anions present, which allows for the fine-tuning of different cage geometries.

Pillared-layer Ni-MOF nanosheets anchored on TiC MXene for enhanced electrochemical energy storage.

The poor conductivity, unsatisfactory stability and easy aggregation of metal-organic framework (MOF) nanomaterials have been recognized as the main reasons that prevent their practical application. Here, we report the highly conductive and cyclic-stable TiC MXene@pillared-layer [Ni(thiophene-2,5-dicarboxylate)(4,4'-bipyridine)] MOF composites (MXene@Ni-MOF). Based on the hard-soft-acid-base principle, the pillared-layer Ni-MOF porous structure with Ni-N coordination bonds confer better structural stability.