Structure, electronic configuration, and Mössbauer parameters of an antiferromagnetic

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1 Structure, electronic configuration, and Mössbauer parameters of an antiferromagnetic Fe 2 -peroxo intermediate of methane monooxygenase Teepanis Chachiyo and Jorge H. Rodriguez Theoretical and Computational Biomolecular Physics Group Department of Physics, Purdue University, West Lafayette, IN , USA Supplementary Information Table S1. Cartesian coordinates (Å) corresponding to final (89 atom) optimized structure of MMOH Peroxo. [F] indicates the six α carbons kept frozen during optimization C [F] C C C O O C [F] C C C O O C [F] C C N C C N C C C O O Present address: Department of Physics, Khon Kaen University, Thailand. teepanis@kku.ac.th jhrodrig@purdue.edu 1

2 C [F] C C C O O C [F] C C N C C N O C [F] H H H H H H H H H H H H H H H H H H H H H H H H H H H H

3 H H H H H H H H H H H H H H H H H H

4 Fig. S1. Representation of skeleton of MMOH peroxo structure displaying the six α carbons kept frozen during optimization of final 89 atom model. These six carbons are labelled [F] in Table S1. 4

Initial Optimized Core geometries 1.88 114.9 1.47 119.5 1.86 I 3.45 1.98 1.96 1.53 1.

Initial feasibility 53 atom Models I, II, and III for MMOH-O 2 used as candidate

All structures were optimized at the U-B3LYP level with a 6-311G* (5D, 7F) basis for

The starting model for the active site was obtained from the crystallographic

5 Initial Optimized Core geometries I II III 3.23 Fig. S2. Initial feasibility 53 atom Models I, II, and III for MMOH-O 2 used as candidate structures to test possible correlations with experimental Mössbauer parameters. All structures were optimized at the U-B3LYP level with a 6-311G* (5D, 7F) basis for iron and 3-21G* for all other atoms. The starting model for the active site was obtained from the crystallographic structure corresponding to the MMOH Reduced state (PDB ID: 1FYZ). The dioxygen unit was added to the model in various binding configurations as shown in the Figure. 5

Initial Optimized Core geometries OH 1.92 91.5 1.

85 V 3.42 OH OH 1.88 115.0 1.50 2.16 119.6 VI 3.

Initial feasibility 53 atom Models IV, V, and VI

test possible correlations with experimental

All structures were optimized at the U-B3LYP

obtained from the crystallographic structure

6 Initial Optimized Core geometries OH IV V 3.42 OH OH VI 3.55 Fig. S3. Initial feasibility 53 atom Models IV, V, and VI for MMOH-O 2 used as candidate structures to test possible correlations with experimental Mössbauer parameters. All structures were optimized at the U-B3LYP level with a 6-311G* (5D, 7F) basis for iron and 3-21G* for all other atoms. The starting model for the active site was obtained from the crystallographic structure corresponding to the MMOH Reduced state (PDB ID: 1FYZ). The dioxygen unit was added to the model in various binding configurations as shown in the Figure. 6

7 Table S2. Computed isomer shifts and quadrupole splittings for initial feasibility 53 atom candidate structures shown in Figs. S2-S3. The geometries were optimized at the UB3LYP level with the 6-311G* (5D,7F) basis for iron and 3-21G* basis for all other atoms as described in the caption of Figs. S2-S3. After geometry optimization, an additional single point calculation at the UB3LYP level using the 6-311G* (5D. 7F) basis for all atoms was carried out to compute Mössbauer parameters. δ Computed Fe [mm/s] Computed EQ [mm/s] Structure I II III IV V VI To facilitate comparison the calculated Mössbauer spectral parameters for the final 89 atom optimized structure are also shown in Table S3. These parameters have already been given in the main text Table 1. Table S3. Computed isomer shifts and quadrupole splittings for final optimized 89 atom structure shown in Fig. 1 of the main text with coordinates given in Table S1. The geometry was optimized at the UB3LYP level with the 6-311G* (5D,7F) basis for the iron atoms and all atoms bound to them (see main text for further details). Other atoms used the 3-21G* basis. δ Computed Fe [mm/s] Computed EQ [mm/s] Structure MMOH Peroxo Table S4. Comparison of two different methods for the computation of quadrupole splittings for final optimized 89 atom structure of MMOH Peroxo shown in Fig. 1 of the main text with coordinates given in Table S1. Computational Vzz Computed [a.u.] a η Computed Q [barn] Computed EQ [mm/s] Method Training Set: Equation 5 Using Q: Equations 2 & 3 a Convertion factor of V zz from a.u. to SI units: V/m 2. 7

8 Table S5. For comparison, predicted electric field gradients for members of the training set making use of Eqs. 2 and 3 in the main text are presented. Experimental values for E Q given in Table 4 and Q = 0.16 barn have been used. In the absence of reliable values of η for some complexes, the values computed at the U-B3LYP/6-311G* level as reported in Table 4 have been used. Complex S Predicted from Eqs.2 3 VZZ [a.u.] a CpFe(CO) 2 Cl Fe(CO) 3 (1,4-butadiene) Fe(CO) 3 (cycle-butadiene) Fe(CO) FeO a Convertion factor of V zz from a.u. to SI units: V/m 2. 8

Supplementary Figure S1 Stable structures of I, I', II, and II' optimized at the

Supplementary Figure S1 Stable structures of I, I', II, and II' optimized at the H C Si 2.492 (2.348) 1.867 (2.005) Fe O 2.106 (2.077) 2.360 (2.497) N 1.126 (1.115) 2.105 (2.175) I quintet (triplet) 0.0 (+4.1) kcal/mol II triplet (quintet) 0.0 (+4.3) kcal/mol 1.857 (2.076) 2.536 (2.351)