Theoretical Investigations on the Agostic Interactions of the Molybdenum and Manganese Complexes

The essential participation of agostic interactions in C-H bond activation, cyclometallation and other catalytic processes has been widely observed. To quantitatively evaluate the Mo-H-C agostic interaction in the Mo beta/gamma- agostomers [CpMo(CO)(2)(PiPr(3))](+) (Mo, 1 and Mo, 2) and the Mn-H-C agostic interaction in the Mn alpha/epsilon-agostomers [(C6H9]Mo(CO)(3)] (Mn, 1 and Mn, 2), the comprehensive density functional theory (DFT) theoretical investigations were performed. Results indicated that the Mo beta-agostomer 1 is only favorable by 0.5 kcal mol(-1) than Mo gamma-agostomer 2, and the Gibbs barrier for their interconversion was 9.1 kcal mol(-1). A slightly higher Gibbs barrier of 12.7 kcal mol(-1) for the isomerization between the Mn alpha/epsilon-agostomers was also obtained. The relatively strong agostic interactions in Mo beta-agostomer 1 and Mn alpha-agostomer 1 were further verified by the AIM (Atoms-In-Molecules) analyses and the NAdOs (natural adaptive orbitals) analyses. The findings on the agostic interaction presented in this study are believed to benefit the understandings of the agostic interaction involved catalytic processes and to promote the development of new organometallic complexes.

Automated summary

The essential role of agostic interactions in various catalytic processes has been widely observed. Density functional theory (DFT) calculations were performed to evaluate the agostic interactions in the Mo beta/gamma-agostomers and Mn alpha/epsilon-agostomers. The results showed that the difference in energy between Mo beta-agostomer 1 and Mo gamma-agostomer 2 is only 0.5 kcal mol(-1), and the Gibbs barrier for their interconversion is 9.1 kcal mol(-1). Similarly, the isomerization between Mn alpha/epsilon-agostomers has a Gibbs barrier of 12.7 kcal mol(-1). The strong agostic interactions in Mo beta-agostomer 1 and Mn alpha-agostomer 1 were further confirmed by AIM and NAdOs analyses. These findings contribute to the understanding of agostic interactions in catalytic processes and the development of new organometallic complexes.