The study of coordinate process of Chiral Diiminodiphophine Ligand with Ruthenium by in situ variable temperature 31P NMR and computer modeling

The coordinate process of Chiral Diiminodiphophine Ligand with Ruthenium is investigated with in situ variable temperature 31P NMR and computer modeling. At first the chemical shifts of ligand and the six-coordinated complex are determined at - 13. 0ppm and 48. 2ppm, respectively. During the coordinate process at the temperature between 293K and 313K, the four- and five-coordinated intermediates are produced one after the other. The four-coordinated intermediate has two signals at 30. 8ppm and - 15. 0ppm, and the five-coordinated intermediate has two peaks at 35. 1ppm and - 16. 5ppm. At 343K only the six-coordinated complex is found in the product, it's signal appears at 48. 2ppm. Molecular modeling is used to show their conformations. All coordinated complexes are constructed and optimized with molecular mechanics and molecular dynamics. The calculation results show that the four-coordinated complex has two conformers with an energy difference of 9kcal (.) mol (-1), which are in equilibrium. The five-coordinated intermediate has only one preferred conformation with a single uncoordinated P atom. The calculated construction of six-coordinated complex reveals that two chloride atoms located on both sides perpendicular to the planar consisted from PNNP atoms. The conformation energy is 162. 0kcal (.) mol (-1), to which the bond angle energies contribute 112. 5kcal (.) mol (-1), and the electrostatic energy is - 41. 4kcal (.) mol(-1). This means that the electrostatic interactions are benefit to producing completely coordinate product. At the same time the convergent ligand molecule bears larger bond angle torsions.