Benchmark Study of Density Functional Theory Methods in Geometry Optimization of Transition Metal-Dinitrogen Complexes

The current benchmark study is focused on determiningthe mostprecise theoretical method for optimizing the geometry of transitionmetal-dinitrogen complexes. To accomplish this goal, sevendensity functional (DF) methods from five distinct classes of densityfunctional theory (DFT) have been selected, including B3LYP-D3(BJ),BP86-D3(BJ), PBE0-D3(BJ), & omega;B97X-D, M06, M06-L, and TPSSh-D3(BJ).These DFs will be utilized with the Karlsruhe basis set (def2-SVP).To carry out this benchmark study, a total of forty-two structurallydiverse transition metal-dinitrogen compounds with experimentallyknown X-ray data have been selected from the Cambridge CrystallographicData Centre (CCDC). Based on a comparison of the theoretical datawith experimental values (X-ray) of the selected transition metal-dinitrogencompounds, statistical parameters such as root-mean-square deviation(RMSD) and N-N and M-N bond lengths are obtained toevaluate the performance of the seven chosen DFs. According to theobtained results, among all DFT methods used in the study, Minnesotafunctionals (M06 and M06-L) and TPSSh-D3(BJ) show good performance,with lower RMSD values. This suggests that these three methods arethe most reliable for optimizing the geometry of transition metal-dinitrogencomplexes. Based on the absolute errors of the N-N and M-Nbond lengths relative to the X-ray data, further analysis is conducted,and it is determined that M06-L is the best functional for optimizingthe geometry of transition metal-dinitrogen compounds. Additionally,the influence of using a high-level basis set (def2-TZVP) comparedto def2-SVP on the calculated RMSD among the seven chosen methodsis found to be negligible.

Automated summary

The current study aims to determine the most precise theoretical method for optimizing the geometry of transition metal-dinitrogen complexes. Seven density functional methods were selected and applied to forty-two transition metal-dinitrogen compounds. The results indicate that M06, M06-L, and TPSSh-D3(BJ) are the most reliable methods for optimizing the geometry of these complexes, with M06-L being the best.