Carbopalladation of nitriles: synthesis of 2,3-diarylindenones and polycyclic aromatic ketones by the Pd-catalyzed annulation of alkynes and bicyclic alkenes by 2-iodoarenenitriles

2-iodobenzonitrile, its derivatives, and various heterocyclic analogues undergo palladium(0)-catalyzed annulation onto diarylacetylenes or bicyclic alkenes to afford 2,3-diarylindenones and polycyclic aromatic ketones in very good to excellent yields. This reaction represents one of the first examples of the addition of an organopalladium moiety to the carbon-nitrogen triple bond of a nitrile. The reaction is compatible with a number of functional groups. A reaction mechanism, as well as a model accounting for the electronic effects of substituents on the aromatic ring of the nitrile, is proposed.     

2D Titania–Carbon Superlattices Vertically Encapsulated in 3D Hollow Carbon Nanospheres Embedded with 0D TiO2 Quantum Dots for Exceptional Sodium‐Ion Storage

Two‐dimensional (2D) superlattices offer promising technological opportunities in tuning the intercalation chemistry of metal ions. Now, well‐ordered 2D superlattices of monolayer titania and carbon with tunable interlayer‐spacing are synthesized by a molecularly mediated thermally induced approach. The 2D superlattices are vertically encapsulated in hollow carbon nanospheres, which are embedded with TiO₂ quantum dots, forming a 0D‐2D‐3D multi‐dimensional architecture. The multi‐dimensional architecture with the 2D superlattices encapsulated inside exhibits a near zero‐strain characteristic and enriched electrochemical reactivity, achieving a highly efficient Na⁺ storage performance with exceptional rate capability and superior long‐term cyclability.     

Ultra‐Tough Inverse Artificial Nacre Based on Epoxy‐Graphene by Freeze‐Casting

Epoxy nanocomposites combining high toughness with advantageous functional properties are needed in many fields. However, fabricating high‐performance homogeneous epoxy nanocomposites with traditional methods remains a great challenge. Nacre with outstanding fracture toughness presents an ideal blueprint for the development of future epoxy nanocomposites. Now, high‐performance epoxy‐graphene layered nanocomposites were demonstrated with ultrahigh toughness and temperature‐sensing properties. These nanocomposites are composed of ca. 99 wt % organic epoxy, which is in contrast to the composition of natural nacre (ca. 96 wt % inorganic aragonite). These nanocomposites are named an inverse artificial nacre. The fracture toughness reaches about 4.2 times higher than that of pure epoxy. The electrical resistance is temperature‐sensitive and stable under various humidity conditions. This strategy opens an avenue for fabricating high‐performance epoxy nanocomposites with functional properties.     

A first-principles investigation on interactions between various surface-terminated diamond films

To elucidate the influence of different terminations on diamond surface interaction, the geometry and electronic structures of the diamond films modified by different terminations (H, F, O, NH₂, and OH) are studied by using the first principles method. Strong bonding is formed between the clean diamond surfaces, which suggest an obvious interface interaction. Both H and F terminals have significant effects on the reduction of the interface interactions. Due to the larger difference in electronegativity between C and F, the F termination layer has a higher electron density coverage to give a larger repulsive force. Therefore, the interaction between the F-terminated diamond interfaces is stronger than that between the H-terminated diamond interfaces. The O-terminated diamond surfaces are unstable. The NH₂- and OH-terminals have weak interaction due to the presence of large functional group atoms that leads to an electronic offset.     

Two—dimensional Network Crown Ether Complex.Synthesis and Crystal Structure of 18—Crown—6 Complex：[K（18—C—6）]2[Cd—（nmt）2]

The novel complex [K(18-C-6)]2[Cd(mnt)2][18-C-6-18-crown-6,nmt=1,2-dicyanoethene-1,2-dithiolate,C2S2-(CN)2^2-] was synthesized and characterized by elemental analysis,IR spectrum and X-ray diffraction analysis.The complex displays two-dimensional network structure of [K(18-C-6)] complex segments and [Cd(nmt)2] complex segment bridged by S-K-S,S-K-N and N-K-N interactions between adjacent[K(18-C-6)] and [Cd(mnt)2]units.     

Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative

~~Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative@赵红卫$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @江致勤$Department of Chemistry, Tongji Unviersity!Shanghai 200092,China @窦大营$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @吴铁一$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @王文锋$Shanghai…     

Reactivity of the Hydroxy Groups in Melezitose and Their Selective Protection

The reactivity of melezitose hydroxy groups was studied by tritylation in pyridine with subsequent acetylation. After partial detritylation of the products, acetyl group transfer from position 4 to 6 was observed. The structure of the prepared melezitose derivatives was established on the basis of their IR, ¹H, ¹³C, and ¹H-¹H COSY NMR, and mass spectra (fast atom bombardment), as well as from the results of model calculations performed with the aid of SGI Indigo Molecule-Pattern-Work-Station software package (Biosym) where the potential energy function was approximated with the CVFF potential. The reactivity of primary hydroxy groups in melezitose was found to decrease in the following order: 6' > 6 6' > 1'.     

Cube‐like 12‐MC‐4 and Offset Stacked 10‐MC‐3 Metallacrowns: Synthesis,Structure, and Magnetic Properties

Two complexes [Mn^III₄(naphthsao)₄(naphthsaoH)₄] ( 1 ) and [Fe^III₆O₂(naphthsao)₄(O₂CPh)₆] ( 2 ) [naphthsao = 1‐(1‐hydroxy‐naphthalen‐2‐yl)ethanone oxime] were obtained through the reactions of naphthsao ligand and MnCl₂ · 4H₂O or FeCl₃ · 6H₂O in the presence of triethylamine (Et₃N). Their structures were determined by X‐ray single crystal diffraction, elemental analysis, and IR spectra. Complex 1 displays 12‐MC‐4 metallacrown structural type with cube‐like configuration and 2 shows an offset stacked 10‐MC‐3 structural type with the ring connectivity containing Fe–O–C–O–Fe–O–N–Fe–O–N. Magnetic susceptibility measurement reveals the ferromagnetic interactions and field‐induced slow relaxation of the magnetization for 1 , whereas out‐of‐phase signal is not observed for 2 .     

A new three‐dimensional cobalt(II) coordination polymer based on V‐shaped 3,4′‐oxydibenzoate: synthesis,crystal structure and magnetic properties

A new coordination polymer (CP), namely poly[(μ‐4,4′‐bipyridine)(μ₃‐3,4′‐oxydibenzoato)cobalt(II)], [Co(C₁₄H₈O₅)(C₁₀H₈N₂)]_n or [Co(3,4′‐obb)(4,4′‐bipy)]_n ( 1 ), was prepared by the self‐assembly of Co(NO₃)₂·6H₂O with the rarely used 3,4′‐oxydibenzoic acid (3,4′‐obbH₂) ligand and 4,4′‐bipyridine (4,4′‐bipy) under solvothermal conditions, and has been structurally characterized by elemental analysis, IR spectroscopy, single‐crystal X‐ray crystallography and powder X‐ray diffraction (PXRD). Single‐crystal X‐ray diffraction reveals that each Co^II ion is six‐coordinated by four O atoms from three 3,4′‐obb^2? ligands, of which two function as monodentate ligands and the other as a bidentate ligand, and by two N atoms from bridging 4,4′‐bipy ligands, thereby forming a distorted octahedral CoN₂O₄ coordination geometry. Adjacent crystallographically equivalent Co^II ions are bridged by the O atoms of 3,4′‐obb^2? ligands, affording an eight‐membered Co₂O₄C₂ ring which is further extended into a two‐dimensional [Co(3,4′‐obb)]_n sheet along the ab plane via 3,4′‐obb^2? functioning as a bidentate bridging ligand. The planes are interlinked into a three‐dimensional [Co(3,4′‐obb)(4,4′‐bipy)]_n network by 4,4′‐bipy ligands acting as pillars along the c axis. Magnetic investigations on CP 1 disclose an antiferromagnetic coupling within the dimeric Co₂ unit and a metamagnetic behaviour at low temperature resulting from intermolecular π–π interactions between the parallel 4,4′‐bipy ligands.     

General π‐Electron‐Assisted Strategy for Ir,Pt, Ru,Pd, Fe,Ni Single‐Atom Electrocatalysts with Bifunctional Active Sites for Highly Efficient Water Splitting

Both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial to water splitting, but require alternative active sites. Now, a general π‐electron‐assisted strategy to anchor single‐atom sites (M=Ir, Pt, Ru, Pd, Fe, Ni) on a heterogeneous support is reported. The M atoms can simultaneously anchor on two distinct domains of the hybrid support, four‐fold N/C atoms (M@NC), and centers of Co octahedra (M@Co), which are expected to serve as bifunctional electrocatalysts towards the HER and the OER. The Ir catalyst exhibits the best water‐splitting performance, showing a low applied potential of 1.603 V to achieve 10 mA cm^?2 in 1.0 m KOH solution with cycling over 5 h. DFT calculations indicate that the Ir@Co (Ir) sites can accelerate the OER, while the Ir@NC₃ sites are responsible for the enhanced HER, clarifying the unprecedented performance of this bifunctional catalyst towards full water splitting.