Ferrocene derived P,S-heterodonor ligands were effectively used in AgOAc catalyzed asymmetric cycloaddition of azomethine ylides. The roles of planar chirality and electronic properties of the phosphorous substituents have been examined, and up to 93% ee was obtained. 2007 Elsevier Ltd. All rights reserved. The 1,3-dipolar cycloaddition reaction has become a powerful synthetic tool, providing a...

Lipid domains are found in systems such as multicomponent bilayer membranes and single component monolayers at the air-water interface. It was shown by Keller et al. [J. Phys. Chem. 91, 6417 (1987)] that in monolayers, the size of the domains results from balancing the line tension, which favors the formation of a large single circular domain, against the electrostatic cost of assembling the di...

We demonstrate constraint of peptide backbone and side-chain conformation with 3D (1)H-(15)N-(13)C-(1)H dipolar chemical shift, magic-angle spinning NMR experiments. In these experiments, polarization is transferred from (15)N[i] by ramped SPECIFIC cross polarization to the (13)C(alpha)[i], (13)C(beta)[i], and (13)C(alpha)[i - 1] resonances and evolves coherently under the correlated (1)H-(15)N...

dipolar-dephasing method provides some information about the strength of dipolar coupling in solids. dipolar dephasing technique measures the time for a polarized carbon nucleus to lose its magnetization once the proton locking field is terminated. the dynamics of guest molecules adsorbed within the cavities and channels of nonporouszeolite strongly depend on the structure and chemical composit...

We have studied needle shaped three-dimensional classical spin systems with purely dipolar interactions in the microcanonical ensemble, using both numerical simulations and analytical approximations. We have observed spontaneous magnetization for different finite cubic lattices. The transition from the paramagnetic to the ferromagnetic phase is shown to be first-order. For two lattice types we ...

A “parallel plate” model describing the electrostatic potential energy of protein-protein interactions is presented that provides an analytical representation of the effect of ionic strength on a bimolecular rate constant. The model takes into account the asymmetric distribution of charge on the surface of the protein and localized charges at the site of electron transfer that are modeled as el...