Thermal parameters of 11,11-dimethyltricyclo [4,4,1,01,6] undeca-2,4,7,9-tetraene: A lattice-dynamical discussion

An unusual CC bond length (1.81 A) is observed in a derivative of [10] annulene; a possibility of coexistence of two different isomers in the same crystal structure is definitely ruled out by a lattice-dynamical analysis of thermal motion.     

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Iminophosphine-palladium(0) complexes as highly active catalysts in the Suzuki reaction. Synthesis of undecaaryl substituted corroles

The iminophosphine-palladium(0) complex [Pd(dmfu)(P-N)] [dmfu=dimethyl fumarate; P-N=2-(PPh₂)C₆H₄-1-CHNC₆H₄-4-OMe] is a very efficient catalyst for the Suzuki coupling. In the reaction of aryl bromides with phenylboronic acid, turnover numbers up to ca. 200,000 are obtained at 110 °C in 2 h. Good rates are obtained also with the sterically hindered and electronically deactivated 2-bromo-1,3,5-trimethylbenzene. The complex is able to catalyze the exhaustive arylation of 2,3,7,8,12,13,17,18-octabromo-5,10,15-triphenylcorroleCu(III) to yield the corresponding undecaaryl substituted derivative.     

Barmer to internal rotation in the methylammonium ion

As experimentally available data only give indirect information about geometrical and electronic properties of the methylammonium ion, ab initio MO-LCAO-SCF calculations, with different minimal and extended basis sets, have been performed on this ion to determine its optimized geometry and internal rotation barrier. Results suggest the existence of a hindered internal rotation with a barrier of about 2 kcal mole^?1.     

Biogenetic-Type Total Synthesis of (±)-2-Deoxystemodinone. Preliminary Communication

A biogenetic-type total synthesis of(±)-2-deoxystemodinone ( 1 ), by solvolytic rearrangement of the 1-methyl[2.2.2]oct-2-yl methanesulphonate 4 , is described.     

Finite element and finite volume‐element simulation of pseudo‐ECGs and cardiac alternans

In this paper, we are interested in the spatio‐temporal dynamics of the transmembrane potential in paced isotropic and anisotropic cardiac tissues. In particular, we observe a specific precursor of cardiac arrhythmias that is the presence of alternans in the action potential duration. The underlying mathematical model consists of a reaction–diffusion system describing the propagation of the electric potential and the nonlinear interaction with ionic gating variables. Either conforming piecewise continuous finite elements or a finite volume‐element scheme are employed for the spatial discretization of all fields, whereas operator splitting strategies of first and second order are used for the time integration. We also describe an efficient mechanism to compute pseudo‐ECG signals, and we analyze restitution curves and alternans patterns for physiological and pathological cardiac rhythms. Copyright © 2014 John Wiley & Sons, Ltd.