DFT, DLPNO‐CCSD(T), and NEVPT2 benchmark study of the reaction between ferrocenium and trimethylphosphine

Abstract

The reaction between ferrocenium and trimethylphosphine was studied using density functional theory (DFT), domain‐based local pair natural orbital coupled cluster theory with single‐, double‐, and perturbative triple excitations (DLPNO‐CCSD(T)), and N‐electron valence state perturbation theory (NEVPT2). The accuracy of the DFT functionals decreases compared to the DLPNO‐CCSD(T) level in the following order: M06‐L > TPSS > M06, BLYP > PBE, PBE0, B3LYP > > PWPB95 > > DSD‐BLYP. The roles of thermochemical, continuum solvation (SMD), and counterpoise corrections were evaluated. Grimme's D3 empirical dispersion correction is essential for all functionals studied except M06 and M06‐L. The reliability of the frequency calculations performed directly within the SMD was confirmed. The systems showed no significant multireference character according to T1 and T2 diagnostics and the fractional occupation number (FOD) weighted electron density analysis. The multireference NEVPT2 calculations gave qualitatively valid conclusions about the reaction mechanism. However, a multireference approach is generally not recommended because it requires arbitrary chosen active spaces.

Computational Protocol to Calculate the Phosphorescence Energy of Pt(II) Complexes: Is the Lowest Triplet Excited State Always Involved in Emission? A Comprehensive Benchmark Study

“…Here, the performance of the DLPNO-CCSD(T) 20 method to calculate phosphorescence energies in phosphors is assessed for the first time. [22][23][24][25] The calculation of accurate phosphorescence energies has been proven difficult for Pt (II) complexes. 26,27 Many pseudo-square planar Pt (II) complexes displaying various cyclometalating and ancillary ligands have been synthesized and characterized in the literature.…”

Rotation of the η3‐Propargyl Ligand in [(C6Me5H)M(CO)2(η3‐C3H3)]+ (M=Cr, Mo, W) Complexes

“…Therefore, only the η 3 ‐η 3 ‐η 3 pathway is possible at reasonable temperatures and can be studied using dynamic NMR. More accurate high‐level DLPNO‐CCSD(T) [19–21] computations resulted in an activation energy of +20.6 kcal mol −1 , which was slightly lower than the activation energy obtained using DFT (Table S2). The variance from the experimental value (+16.4 kcal mol −1 ) [17] can be attributed to the experimental uncertainty of the dynamic NMR method.…”

Charge Transfer Parameters, Correlative Perturbation Potential with Non‐Linear Optical Properties of Bi‐Heterocyclic Dyes Having TCF Acceptor‐ DFT Approach

“…The finite field (FF) approach is used as implemented in Gaussian 09. In the absence of experimental NLO reference values, it is difficult to evaluate accuracy of the data directly [78] . Using the central tendencies (the mean values in each case) we have treated the data statistically.…”