Designing and synthesis of phosphine derivatives of Ru3(CO)12 - Studies on catalytic isomerization of 1-alkenes

A comparative investigation on the isomerization reactions of 1-alkenes to their corresponding 2-alkenes catalyzed Ru-3(CO)(12) (1), Ru-3(CO)(9)(PEt3)(3) (2) and Ru-3(CO)(10)(dppe) (3), (where dppe = 1,2-bis(diphenylphosphino) ethane) is described. Both the complexes of types 2 and 3 were characterized by all analytical and spectroscopic data. The molecular structure of 2 was confirmed by single-crystal X-ray analysis. It is observed that the nature of phosphine ligands plays an important role in the isomerization of 1-alkenes. When the chelated diphosphine is used, the internal isomerization reaction by [Ru-3(CO)(10)(dppe)] (3) is completed relatively in less time compared to other derivatives. As per the DFT calculations, the observed reaction rate for the alkene isomerization may be explained based on the relative stability of 1, 2, and 3. The CO abstraction step is highly feasible in 3, the least stable among the three, thus the reaction occurs at the highest rate. Due to the increased relative stability from 2 to 1, the reaction requires more time at elevated temperatures and the rate decreases as a consequence.

Automated summary

The study found that the nature of phosphine ligands plays a significant role in the isomerization of 1-alkenes, with chelated diphosphine leading to a relatively faster completion of internal isomerization reaction. Density functional theory calculations indicate that the reaction rate is linked to the relative stability of 1, 2, and 3, with the least stable 3 showing the highest reaction rate.