DFT study of adiabatic singlet-triplet energy gaps in Ni(II)-based macrocyclic-ligand supramolecular complexes

Abstract

The efficiency of different hybrid and meta-hybrid DFT exchange-correlation functionals (B3LYP, B3LYP*, B3LYP-D, CAM-B3LYP, CAM-B3LYP-D, HSE06, ωB97XD, M06L, M06, M062X, M11L, M11, MN12-L, MN12-SX, N12 and N12-SX) in describing the adiabatic singlet-triplet energy gap as well as the geometry conformations obtained with singlet and triplet spin states have been investigated in the case of the organometallic complex of Ni-tetrakis-(pentafluorophenyl)porphyrin-phenazopyridine. The results show that proper consideration of the dispersion effects as well as the amount of Hartree-Fock (HF) exchange is very important in order to have a balanced description for the electronic energies and geometry coordinates, otherwise, we can get significantly different results for different XC functionals. By using functionals with moderate HF-exchange it is possible to get a fortuitous cancellation of errors between the static correlation effects and the self-interaction errors.The efficiency of different hybrid and meta-hybrid DFT exchange-correlation functionals (B3LYP, B3LYP*, B3LYP-D, CAM-B3LYP, CAM-B3LYP-D, HSE06, ωB97XD, M06L, M06, M062X, M11L, M11, MN12-L, MN12-SX, N12 and N12-SX) in describing the adiabatic singlet-triplet energy gap as well as the geometry conformations obtained with singlet and triplet spin states have been investigated in the case of the organometallic complex of Ni-tetrakis-(pentafluorophenyl)porphyrin-phenazopyridine. The results show that proper consideration of the dispersion effects as well as the amount of Hartree-Fock (HF) exchange is very important in order to have a balanced description for the electronic energies and geometry coordinates, otherwise, we can get significantly different results for different XC functionals. By using functionals with moderate HF-exchange it is possible to get a fortuitous cancellation of errors between the static correlation effects and the self-interaction errors.