Sz~rnmnr~~ . From a molecular orbital study of model systems we derivc the electronic requiremcnts for the Grob fragmentation. The necessary condition for an allowed fragmentation in an ?I-C,-C,-C,-N system, or the amino cation +C,-C,-C,-N is the level ordering A below S . This in turn is set by maximal through-bond coupling of the empty cation orbital and the nitrogen lone pair. The conformati...

A novel photoredox-catalyzed C(sp 3 )–C(sp ) cross-coupling between N -arylamines and cycloketone oxime esters under mild conditions has been accomplished.

designing a power splitter with five ports has been shown in this article. in order to prevent the direct coupling between waveguides, a t-shaped structure with an appropriate distance has been used. the coupling between the parallel photonic crystal waveguides is based on multimode interference, while selecting the output efficiency is performed by setting the refractive coefficients and radiu...

hemicellulose of southern yellow pine wood spices was extracted by pressurized hot water at three different temperatures: 140°c, 155°c and 170°c. compounding with pp (polypropylene) was performed by extrusion after preparing wood flour and sieving to determine its mesh size. the ratio of wood to polymer was 50:50 based on oven-dry weight of wood flour. all extraction treatments and control samp...

It is proven that the inverse localization length of an Anderson model on a strip of width L is bounded above by L/λ2 for small values of the coupling constant λ of the disordered potential. For this purpose, a formalism is developed in order to calculate the bottom Lyapunov exponent associated with random products of large symplectic matrices perturbatively in the coupling constant of the rand...

N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h(-1) at 25°C and the irradiation...

The 1 N hyperfine multiplets of low-7 rotational transitions of the E and Z isomers of HN = CH — C = N, produced by flash pyrolysis from (CH 3 ) 2N —C = N as precursor, were observed and analysed. The quadrupole coupling constants determined are (c-axis perpendicular to the molecular plane): , Xaa/MHz XJUWz XJUHz E H — N = CH — C = N -4 .160(10) +1.658(31) +2.502(31) E H N = C H C = N +0.764(11...