Shock tube and modeling study of propene pyrolysis

The thermal decomposition of propene behind reflected shock waves with 1200 < T₅ < 1800 K and 1.6 × 10^?5 < ρ₅ < 2.7 × 10^?5 mol/cm³ was studied by IR laser kinetic absorption spectroscopy and gas-chromatographic analysis of reaction products. The present data together with earlier shock tube data were satisfactorily modeled with a 51-reaction mechanism. As the initial step of the reaction, three channels, C₃H₆ = CH₃ + C₂H₃ (1), C₃H₆ = H + AC₃H₅ (2), and C₃H₆ = CH₄ + C₂H₂ (3), were necessary to interpret all the experimental data. © John Wiley & Sons, Inc.     

Maximal minors of a matrix with linear form entries

Let P be a matrix whose entries are homogeneous polynomials in n variables of degree one over an algebraically closed field. We show that the maximal minors, say m-minors, of P generate the linear space of homogeneous polynomials of degree m if P has the maximal rank m at every point of the affine n-space except the origin.     

Novel Mg-responsive fluorescent chemosensor based on benzo-15-crown-5 possessing 1-naphthaleneacetamide moiety

A new fluorescent ionophore for Mg²⁺, 4′-(1-naphthaleneacetamido)benzo-15-crown-5 (1), was synthesized, and its complexation behavior in acetonitrile was investigated by means of UV and fluorescence spectrometry. In the absence of a metal ion, the naphthalene moiety showed quite weak fluorescence emission (fluorescence ‘Off’ state). On the other hand, after the addition of Mg²⁺, fluorescence emission from the naphthalene moiety increased (fluorescence ‘On’ state).     

Anomalous fluorescent responses of 9-fluorenecarboxamide derivatives possessing benzo-15-crown-5.

A new fluorescent ionophore for alkaline earth metal ions, 4'-(9-fluorenecarboxamido)benzo-15-crown-5 (3), was synthesized; its photochemical behavior was investigated using UV, fluorescence, (1)H NMR, and (13)C NMR spectrometry. In the absence of a metal ion, the fluorene moiety showed weak fluorescence emission (fluorescence "Off" state). However, complexation with metal ions greatly enhanced the fluorescence intensity (fluorescence "On" state).     

Palladium-catalyzed C-H activation/intramolecular amination reaction: a new route to 3-aryl/alkylindazoles

A method for the catalytic C-H activation of hydrazone compounds followed by intramolecular amination is described. It requires the use of a catalytic amount of Pd(OAc)2 in the presence of Cu(OAc)2 and AgOCOCF3, which efficiently effects the cyclization to afford variously substituted indazoles. The reactions proceed under relatively mild conditions and thus tolerate a variety of functional groups, including alkoxycarbonyl and cyano groups and halogen atoms.     

Hyperspherical slow variable discretization method for weakly bound triatomic molecules

We develop a method for calculating the bound state energies and the wave functions of weakly bound triatomic molecular systems. The method is based on the use of hyperspherical coordinates, combined with the slow variable discretization approach. The finite-element methods-discrete variable representation scheme provides an efficient means to solve the coupled-channel hyper-radial equations. Our method is applied to searching for bound states of the (20)Ne(2)H and (4)He(20)NeH triatomic molecules, using the best empirical pairwise interaction potentials. We consider not only zero total nuclear orbital momentum, J = 0, states but also J > 0 states. The (20)Ne(2)H system has been found to possess one bound state each for the J(Π)=0(+),1(-), and 2(+) symmetries, while there exist only one bound state for the (4)He(20)NeH system in the 0(+) symmetry. We shall calculate the bound state energies and analyze the molecular structures of these species in detail.     

Use of dimethyl carbonate as a solvent greatly enhances the biaryl coupling of aryl iodides and organoboron reagents without adding any transition metal catalysts

The coupling reaction of aryl iodides with arylboronic acids to give biaryl compounds can be efficiently performed without adding a transition metal catalyst. The key to success is the use of dimethyl carbonate as a solvent. This finding provides a new strategy for constructing a biaryl linkage.