Table 4. Representative Geometric Parameters in the Active Site of P450nor [Bond Lengths (r in Å), Bond Angles (θ in deg)], and the N–O and Fe–NO Stretching Vibrations (ν in cm–1) Obtained from QM/MM Calculationsa Using Different DFT Functionals and Basis Sets Together with Experimental Values.
| BP86 | B3LYP-D3 | ωB97M-V |
|||
|---|---|---|---|---|---|
| def2-SVP(D)c | def2-SVP(D)c | def2-SVP(D)c | def2-TZVP(PD)d | exptlb | |
| rFe–NO | 1.655 | 1.653 | 1.643 | 1.641 | 1.67 |
| rN–O | 1.160 | 1.137 | 1.121 | 1.115 | 1.15 |
| rFe–S | 2.337 | 2.310 | 2.298 | 2.300 | 2.33 |
| θFe–N–O | 170.0 | 165.0 | 167.5 | 170.0 | 158 |
| νN–O | 1881.3 | 1984.7 | 2097.5 | 2054.6 | 1853 |
| νFe–NO | 608.0 | 610.9 | 641.1 | 642.0 | 530 |
a
The snapshot is taken from NVT4, and the spin state is set to cs-1et.
b
Structural parameters are from X-ray crystal structure117 and frequencies from resonance Raman spectra in solution.135
c
def2-SVPD for the atoms bound to Fe and NO, and def2-SVP for the others.
d
def2-TZVPPD for Fe, the atoms bound to Fe, and NO, and def2-TZVP for the others.