Oxidative homocoupling of arylboronic acids catalyzed by a 4‐aminoantipyrine–Pd(II)complex

A one‐step synthesis of symmetric biaryls is reported under very mild conditions via the homocoupling reaction of substituted arylboronic acids using an air‐ and moisture‐stable 4‐aminoantipyrine–Pd(II) complex as catalyst. The reaction is conducted at a low catalyst loading of 0.1 mol% at room temperature in methanol in the presence of K₂CO₃ as the base and KMnO₄ as the oxidant. The catalytic methodology is shown to be compatible with diverse functional groups and affords the desired biphenyls in good to excellent yields. Copyright © 2015 John Wiley & Sons, Ltd.     

Facile Preparation of Homo‐ and Hetero‐Dimetallic Complexes with a 4‐Phosphino‐Substituted NHC Ligand. Toward the Design of Multifunctional Catalysts

A series of bimetallic complexes have been synthesized that are supported by a 4‐phosphino‐substituted NHC ligand. The use of this stable ligand reduces the number of synthetic steps and allows for a wide range of metal combinations to be introduced into the complexes.     

Quadruplex DNA‐Stabilising Dinuclear Platinum(II) Terpyridine Complexes with Flexible Linkers

Four dinuclear terpyridineplatinum(II) (Pt–terpy) complexes were investigated for interactions with G‐quadruplex DNA (QDNA) and duplex DNA (dsDNA) by synchrotron radiation circular dichroism (SRCD), fluorescent intercalator displacement (FID) assays and fluorescence resonance energy transfer (FRET) melting studies. Additionally, computational docking studies were undertaken to provide insight into potential binding modes for these complexes. The complexes demonstrated the ability to increase the melting temperature of various QDNA motifs by up to 17 °C and maintain this in up to a 600‐fold excess of dsDNA. This study demonstrates that dinuclear Pt–terpy complexes stabilise QDNA and have a high degree of selectivity for QDNA over dsDNA.     

Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles

A facile approach to bimetallic phosphides, Co‐Fe‐P, by a high‐temperature (300 °C) reaction between Co‐Fe‐O nanoparticles and trioctylphosphine is presented. The growth of Co‐Fe‐P from the Co‐Fe‐O is anisotropic. As a result, Co‐Fe‐P nanorods (from the polyhedral Co‐Fe‐O nanoparticles) and sea‐urchin‐like Co‐Fe‐P (from the cubic Co‐Fe‐O nanoparticles) are synthesized with both the nanorod and the sea‐urchin‐arm dimensions controlled by Co/Fe ratios. The Co‐Fe‐P structure, especially the sea‐urchin‐like (Co_0.54Fe_0.46)₂P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.     

Microplastics occurrence and fate in the environment

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Massey products,A∞-algebras,differential equations,and Chekanov homology

We consider (classical and generalized) Massey products on the Chekanov homology of a Legendrian knot, and we prove that they are invariant under Legendrian isotopies. We also construct a minimal A_∞-algebra structure on the Chekanov algebra of a Legendrian knot, we prove that this structure is invariant under Legendrian isotopy, and we observe that its higher multiplications allow us to find representatives for classical Massey products. Finally, we consider differential equations: we remark that the Massey product Legendrian invariants admit a “dynamical interpretation”, in the sense that they provide solutions for a Maurer-Cartan equation posed on an infinite-dimensional bigraded Lie algebra, and we show how to set up and solve a (twisted) Kadomtsev-Petviashvili hierarchy of equations starting from the Chekanov algebra of a Legendrian knot.     

A novel nucleophilic attack to N-enoyl oxazolidinethiones

The oxazolidinethione synthon can act as a chiral auxiliary and nucleophile (S⁻) carrier molecule simultaneously. Surprisingly, the thiolate attacks N-enoyl oxazolidinethiones producing a new heterocycle, as established by X-ray analysis.     

DC-electric-field-modified second-harmonic generation at the Si(100) surface

1 resonances for clean and H covered surfaces shift as a function of the dc field in agreement with experiment. This suggests the presence of built-in electric fields whose strength depends on the H coverage, and which are strongly localized in the subsurface region. Received: 20 September 1998     

Crystal structure of 1beta-hydroxy-beta-homopipitzolone (9-hydroxy-2,6,9-trimethyltricyclo[6,3,1,0(1,6)]dodeca-5,10,11,12-tetraone).

C15H18O5 is orthorhombic, P2(1)2(1)2(1). The unit-cell dimensions at 293 K are a = 6.526(3), b = 10.247(4), c = 21.008(13) A, V = 1404.8(12) A3, Dx = 1.316 g/cm3, and Z = 4. The R value is 0.044 for 1288 observed reflections. The A, B and C rings adopt chair, twist, and half-chair conformations. The absolute configuration is inferred from the C6 stereochemistry of (+)-cedrol. The crystal structure is stabilized by an O-H...O hydrogen bond and van der Waals forces.