Ligand affinities predicted with the MM/PBSA method: dependence on the simulation method and the force field.

The free energy of binding between avidin and seven biotin analogues has been calculated with the molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) method. We have studied how the force field and the method to generate geometries affect the calculated binding free energies. Four different force fields were compared, but we saw no significant difference in the results.

Expanding the scope of Lewis acid catalysis in water: remarkable ligand acceleration of aqueous ytterbium triflate catalyzed Michael addition reactions.

[reaction: see text] Significant rate acceleration of metal-catalyzed Michael addition reactions in water was observed upon addition of small, dibasic ligands. Ytterbium triflate and TMEDA was the most effective combination leading to a nearly 20-fold faster reaction than in the absence of ligand.