Ab initio and DFT studies of the spin–orbit and spin–spin contributions to the zero-field splitting tensors of triplet nitrenes with aryl scaffolds
- 10 March 2011
- journal article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 13 (15), 6970-6980
- https://doi.org/10.1039/c0cp02809f
Abstract
Spin–orbit and spin–spin contributions to the zero-field splitting (ZFS) tensors (D tensors) of spin-triplet phenyl-, naphthyl-, and anthryl-nitrenes in their ground state are investigated by quantum chemical calculations, focusing on the effects of the ring size and substituted position of nitrene on the D tensor. A hybrid CASSCF/MRMP2 approach to the spin–orbit term of the D tensor (DSO tensor), which was recently proposed by us, has shown that the spin–orbit contribution to the entire D value, termed the ZFS parameter or fine-structure constant, is about 10% in all the arylnitrenes under study and less depends on the size and connectivity of the aryl groups. Order of the absolute values for DSO can be explained by the perturbation on the energy level and spatial distributions of π-SOMO through the orbital interaction between SOMO of the nitrene moiety and frontier orbitals of the aryl scaffolds. Spin–spin contribution to the D tensor (DSS tensor) has been calculated in terms of the McWeeny–Mizuno equation with the DFT/EPR-II spin densities. The DSS value calculated with the RO-B3LYP spin density agrees well with the D(Exptl) − DSO reference value in phenylnitrene, but agreement with the reference value gradually becomes worse as the D value decreases. Exchange–correlation functional dependence on the DSS tensor has been explored with standard 23 exchange–correlation functionals in both RO- and U-DFT methodologies, and the RO-HCTH/407 method gives the best agreement with the D(Exptl) − DSO reference value. Significant exchange–correlation functional dependence is observed in spin-delocalized systems such as 9-anthrylnitrene (6). By employing the hybrid CASSCF/MRMP2 approach and the McWeeny–Mizuno equation combined with the RO-HCTH/407/EPR-II//U-HCTH/407/6-31G* spin densities for DSO and DSS, respectively, a quantitative agreement with the experiment is achieved with errors less than 10% in all the arylnitrenes under study. Guidelines to the putative approaches to DSS tensor calculations are given.This publication has 100 references indexed in Scilit:
- The resolution of the identity approximation for calculations of spin-spin contribution to zero-field splitting parametersThe Journal of Chemical Physics, 2010
- High-Spin Nitrene Fine-Structure ESR Spectroscopy in Frozen Rigid Glasses: Exact Analytical Expressions for the Canonical Peaks and A D-Tensor Gradient Method for Line BroadeningApplied Magnetic Resonance, 2009
- First-principle computation of zero-field splittings: Application to a high valent Fe(IV)-oxo model of nonheme iron proteinsThe Journal of Chemical Physics, 2005
- Calculation of the fine structure of the triplet state $$ ilde a^3 A_2 $$ of the ozone molecule by the method of multiconfiguration self-consistent fieldOptics and Spectroscopy, 2005
- Validation study of meta-GGA functionals and of a model exchange–correlation potential in density functional calculations of EPR parametersPhysical Chemistry Chemical Physics, 2002
- Persistent High-Spin Polycarbene. Generation of Polybrominated 1,3,5-Tris-[2-[4-(Phenylcarbeno)-phenyl]ethynyl]benzene (S = 3) and Spin Identification by Two-Dimensional Electron Spin Transient Nutation SpectroscopyJournal of the American Chemical Society, 1998
- FT Pulsed ESR/Electron Spin Transient Nutation (ESTN) Spec-Troscopy Applied to High-Spin Systems in Solids; Direct Evi-Dence of a Topologically Controlled High-Spin Polymer as Models for Quasi ID Organic Ferro-and Superpara-MagnetsMolecular Crystals and Liquid Crystals, 1996
- Topology and Spin Alignment in a Novel Organic High-Spin Molecule, 3,4'-Bis(phenylmethylene)biphenyl, As Studied by ESR and a Generalized UHF Hubbard CalculationJournal of the American Chemical Society, 1994
- Calculation of zero field splitting parameters for trimethylenemethaneThe Journal of Chemical Physics, 1981
- Zero-Field Splittings in Molecular Multiplets: Spin—Spin Interaction of Methylene DerivativesThe Journal of Chemical Physics, 1963