Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with the Michael acceptor, diethyl ethoxycarbonylbutendienoate

Palladium-catalyzed intermolecular cyclocarbonylation of 2-iodoanilines with diethyl ethoxycarbonylbutendienoate produces 2,3,3-triethoxycarbonyl-2,3-dihydro-4(1H)-quinolinone derivatives in moderate to good yields. This protocol involves Michael addition and subsequent carbonylation.     

A new waterNa(+) coordination motif in an unexpected diatrizoic acid disodium salt crystal form

The disodium salt of diatrizoic acid crystallises as a tetragonal channel hydrate structure. One of the incorporated water molecules is coordinated to three individual sodium cations in a unique geometry.     

Higher-order zincates as transmetalators in alkyl-alkyl negishi cross-coupling

Negishi revisited: higher-order alkyl zincates have been subjected to Negishi coupling with alkyl bromides. For the first time, coupling takes place in straight THF, i.e., without a salt additive and a high dielectric co-solvent. This provides evidence that it is the higher-order zincate that undergoes transmetalation to Pd, and not mono-anionic zincates or any of the other species present in the Schlenk equilibrium.     

Ionic diamine rhodium complex catalyzed reductive N-heterocyclization of N-(2-nitroarylidene)amines

Ionic diamine rhodium complexes catalyze the reductive N-heterocyclization of N-(2-nitroarylidene)amines under carbon monoxide to afford the corresponding 2H-indazoles in up to 75% yields.     

(PbS)32: a baby crystal

Theoretical calculations based on density functional theory have found (PbS)(32) to be the smallest cubic cluster for which its inner (PbS)(4) core enjoys bulk-like coordination. Cubic (PbS)(32) is thus a "baby crystal," i.e., the smallest cluster, exhibiting sixfold coordination, that can be replicated to obtain the bulk crystal. The calculated dimensions of the (PbS)(32) cluster further provide a rubric for understanding the pattern of aggregation when (PbS)(32) clusters are deposited on a suitable surface, i.e., the formation of square and rectangular, crystalline nano-blocks with predictable dimensions. Experiments in which mass-selected (PbS)(32) clusters were soft-landed onto a highly ordered pyrolytic graphite surface and the resulting aggregates imaged by scanning tunneling microscopy provide evidence in direct support of the computational results.     

Heterobimetallic lanthanide-gold coordination polymers: structure and emissive properties of isomorphous [(n)Bu4N]2[Ln(NO3)4Au(CN)2] 1-D chains

A new series of lanthanide-containing dicyanoaurate coordination polymers, [(n)Bu(4)N](2)[Ln(NO(3))(4)Au(CN)(2)] (Ln = Nd, Eu, Gd or Tb), were synthesized and structurally characterized. They form an isomorphous series, crystallizing in the space group I2(1)2(1)2(1). The structure is composed of a one dimensional zigzag of Ln-N-C-Au-C-N-Ln chains with no intra- or inter-chain aurophilic interactions. The series is related to and can be described as a reduced dimensionality analogue of the previously studied Ln[Au(CN)(2)](3)·3H(2)O. Unlike the Ln[Au(CN)(2)](3)·3H(2)O series, there is no efficient energy transfer between dicyanoaurate and the lanthanide metal centers in the complexes and they essentially act as two separate emissive chromophores.     

Coupling of the Double Bond Stretching Vibration in Divinyl Ethers

Abstract

Examination of the Infrare and Raman spectra of cis, cis-dipropenyl ether (which was produced by isomerization of diallyl ether) has produced evidence for strong vibrational coupling between the two double-bonds. This ether has strong bands it 1655 cm^?1 in the infrared and at 1691 cm^?1 in the Raman. The 1658 cm^?1 band in the Raman is about 10 fold less intense than the strong polarised band. Thus it appears reasonable to associate the strong IR and Raman bands with the asymmetric and symmetric vibrations shown.     

Bend radiation in optical fibers

Abstract

A new, relatively simple way of calculating bend radiation is developed. As is often done in propagation over gently curved surfaces, the fiber curvature is accounted for by placing a straight fiber in a fictitious medium that is inhomogeneous in the plane of the bend. For a gently curved fiber, the medium is slowly varying and the WKB method is used to approximate the radial field dependence. This solution is related to the unperturbed straight fiber solution through an ansatz consistent with the WKB solution. The propagating modes in this approximation remain orthogonal, allowing an immediate generalization to the multimoded case. The radiation loss per unit length is calculated two ways and is consistent with results in the literature.     

Ensemble Steering, Weak Self-Duality, and the Structure of Probabilistic Theories

In any probabilistic theory, we say that a bipartite state ω on a composite system AB steers its marginal state ω ^B if, for any decomposition of ω ^B as a mixture ω ^B =∑ _i p _i β _i of states β _i on B, there exists an observable {a _i } on A such that the conditional states $\omega_{B|a_{i}}$ are exactly the states β _i . This is always so for pure bipartite states in quantum mechanics, a fact first observed by Schrödinger in 1935. Here, we show that, for weakly self-dual state spaces (those isomorphic, but perhaps not canonically isomorphic, to their dual spaces), the assumption that every state of a system A is steered by some bipartite state of a composite AA consisting of two copies of A, amounts to the homogeneity of the state cone. If the state space is actually self-dual, and not just weakly so, this implies (via the Koecher-Vinberg Theorem) that it is the self-adjoint part of a formally real Jordan algebra, and hence, quite close to being quantum mechanical.     

Spectral Analysis for Stationary Solutions of the Cahn–Hilliard Equation in ℝ d

We consider the spectrum associated with three types of bounded stationary solutions for the Cahn–Hilliard equation on ? ^d , d ≥ 2: radial solutions, saddle solutions (only for d = 2), and planar periodic solutions. In particular, we establish spectral instability for each type of solution. The important case of multiply periodic solutions does not fit into the framework of our approach, and we do not consider it here.