Dynamics of the Staudinger Reaction.

The Staudinger reaction of phosphane and azide has been investigated by Atom-centered Density Matrix Propagation (ADMP) approach to ab initio molecular dynamics (AIMD) in combination with molecular orbital analysis within density functional theory. At room temperature, the reaction pathway with the cis initial attack dominates the Staudinger reaction. Electrostatic interaction, charge transfer, and covalent overlap are responsible for the initial attack and for the system to overcome the initial reaction barrier. The rotation of PH3 and PH vibrations facilitate the isomerization of the system from cis intermediate to the last transition state, which indicates that small substituent groups on phosphane can facilitate the last stage of the Staudinger reaction. During the course of the reaction, the change of the average polarizability correlates positively to the change of the potential energy of the system, which clearly suggests that polar solvents can facilitate the overall reaction by stabilizing all transition states and reducing all reaction barriers.