Containing Iridium, Ruthenium Metal Organic Compounds Involved In The Theoretical Study Of Reaction Mechanism

Density functional theory (DFT) calculations at the B3LYP level of theory are carried out to study and analyze the following two projects. Our major purpose is to investigate the molecular structures, bonding, and mechanisms of the reactions in the three different projects in which most of the species are organometallic compounds.First,with the aid of the density functional theory calculations, the detailed catalytic mechanisms on pressure hydrogenation of ketones are explored by employing the representative reaction of 3-pentanone and hydrogen catalyzed by the model complex IrH3[(Me2PC2H4)2NH], derived from the initial catalytic complex IrH3[('Pr2PC2H4)2NH]. The geometrical transformation involved in the catalytic cycle is also clarified. We also compare the two paths in the process of pentacoordinate iridium complex Int4 coordinating with hydrogen to regenerate the original catalyst. One undergoes a three-membered ring transition state, the other possesses a four-membered ring transition state. As the four-membered ring of the ring strain is less than three-membered ring, the second path possesses a lower reaction energy barrier, reaction will according to the second path. In addition, differences between transfer hydrogenation and pressure hydrogenation are also elucidated, finding that transfer hydrogenation is more favorable since the reaction energy barrier of pressure hydrogenation is higher than the other one. Then experimental conditions required to provide a certain degree of pressure. The geometrical transformation from an octahedron to a Y-type involved in the catalytic cycle is also elucidated in terms of molecular theory of transition metal complexes.Then,by the aid of density functional theory (DFT) calculations we studied the reaction mechanisms of a modelμ-benzoquinone diruthenium complex{CpRu(μ-H)}2(μ-η2:η2-C6H4O2), derived from the experimental compound{Cp*Ru(μ-H)}2(μ-η:η-C6H3RO2) (R=H or R=Me, Cp*=η5-C5Me5), with acetylene both in aprotic and protic solvents. Results of calculations show that the influence of the solvent methanol on the reaction is mainly on the step of acetylene coordination. Enhanced hydrogen bonding is the reason for acceleration of the reaction in protic solvent, which is supported by NBO charge analysis.