Supporting Information. Nonclassical Single-State Reactivity of an Oxo- Iron(IV) Complex Confined to Triplet Pathways

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1 Supporting Information for Nonclassical Single-State Reactivity of an Oxo- Iron(IV) Complex Confined to Triplet Pathways Claudia Kupper, ǁ Bhaskar Mondal, ǁ Joan Serrano-Plana, Iris Klawitter, Frank Neese, Miquel Costas, Shengfa Ye, * and Franc Meyer * Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, Göttingen, Germany. Max-Planck Institut für Chemische Energiekonversion, Stiftstrasse 34-36, Mülheim an der Ruhr, Germany. Institut de Química Computacional i Catàlisi (IQCC), Departament de Quimica, Universitat de Girona, Campus Montilivi, E17071 Girona, Catalonia, Spain. ǁ These authors contributed equally to this work. S1

2 Experimental Figure S1. Plot of the observed reaction rates (kobs) versus concentration of 1 with the conc. of CHD being 60 mm. Table S1. Kinetic data for C H-bond activation by complex 1. k2 (M -1 s -1 ) k2 (M -1 s -1 ) log(k2 ) 9H-Xanthene ,10-DHA ,4-CHD H-Fluorene Figure S2. Plot of the observed reaction rates (kobs) of 1 (1 mm) versus concentration of DHA (black, solid line) and DHA-d4 (green, dotted line) at 40 C (left), 20 C (middle) and 0 C (right) in MeCN. The different slopes correspond to KIEs of 32 ± 8, 18 and 11. In case of the very slow reaction toward DHA-d4 at 40 C, the experiment was repeated several times to estimate the error of this value; only the average kobs-values are depicted in the graph. S2

3 Figure S3. Eyring plot for the reaction of 1 with CHD at various temperatures. Figure S4. Plot of the observed reaction rates kobs of 1 (1 mm) versus concentration of DHA at 40 C, 20 C and 0 C in MeCN (left) and the resulting Eyring plot (right). S3

4 Figure S5. Plot of the observed reaction rates kobs of 1 (1 mm) versus concentration of DHA-d4 at 40 C, 20 C and 0 C in MeCN (left) and the resulting Eyring plot (right). Table S2. Kinetic properties of Fe IV =O complex 2 in C H-bond activation toward DHA and DHA-d4 at different temperatures and the corresponding KIEs. k2 (M 1 s 1 ) KIE DHA DHA-d4 kh/kd 40 C (5) a 32 ± 8 a 20 C C a: The error of these values was derived from repetitive experiments. S4

5 Computational details Multireference Calculation We have performed state-specific complete active space self-consistent filed (SS-CASSCF) followed by N-electron valence perturbation theory (NEVPT2) calculations on the reactants, reactant complexes (RC) and the transition states (TS). All the CASSCF calculations were performed on the B3LYP optimized geometries of the reactants and HAT transitions states. Spin-state energetics for complexes 1 and A between the triplet and quintet states have been computed with three different active spaces, namely, CAS(12,9), CAS(12,14) and CAS(18,12). In order to account for double-shell correlation effects, an active space CAS(12,14) has been constructed with the entire 4d shell of iron. On the other hand, semicore correlation effect due to Fe-3p electrons has been treated with the third active space CAS(18,12). Below are the orbitals involved in the respective active spaces. CAS(12,9): (σeq) (σz) (πx) (πy) (nb-fe 3dxy) (σ * eq) (σ * z) (π * x) (π * y) CAS(12,14): (σeq) (σz) (πx) (πy) (nb-fe 3dxy) (σ * eq) (σ * z) (π * x) (π * y) (Fe-4dxy) (Fe-4dxz) (Fe- 4dyz) (Fe-4dx2-y2) (Fe-4dz2) CAS(18,12): (Fe-3px) (Fe-3py) (Fe-3pz) (σeq) (σz) (πx) (πy) (nb-fe 3dxy) (σ * eq) (σ * z) (π * x) (π * y) For TSs, on top of the minimal active space CAS(12,9) for the reactants, it is mandatory to include two additional orbitals that are description of the Fe C H O bonding and antibonding orbitals. This results in an active space involving fourteen electrons distributed over eleven orbitals, CAS(14,11). Four key orbitals that evolve in the σ- and π-tss of complex 1 are presented in Figure S6. As the iron oxidation states change from the ferryl reactant to the transition states, selective second d-shell (4dxy, 4dxz, 4dyz) of iron are included into the activespace of the TSs to account this effect. The resulting active-space becomes CAS(14,14). S5

Figure S6. Fe C H O orbitals in the σ- and π-tss involving complex 1 and CHD.

clearly visible. Blue lines show the nodal planes in bonding and anti-bonding orbitals.

Dominant configurations of the transition state 3 TSσ of complex 1 calculated by

2 stands for doubly occupied orbitals, 1 stands for singly occupied and 0 stands for

6 Figure S6. Fe C H O orbitals in the σ- and π-tss involving complex 1 and CHD. Bonding orbitals are shown with lower cut-offs so that the bonding interactions become clearly visible. Blue lines show the nodal planes in bonding and anti-bonding orbitals. Table S3. Dominant configurations of the transition state 3 TSσ of complex 1 calculated by CASSCF(14,14). 2 stands for doubly occupied orbitals, 1 stands for singly occupied and 0 stands for unoccupied orbitals. Configuration Weight (%) orbital ordering: (σcho) (nb-fe 3dxy) (σeq) (πy) (πx) (σz) (π * x) (π * y) (σ * z) (σ * eq) (σ * CHO) (Fe-4dxy) (Fe-4dxz) (Fe-4dyz) S6

7 Table S4. Dominant configurations of the transition state 3 TSπ of complex 1 calculated by CASSCF(14,14). 2 stands for doubly occupied orbitals, 1 stands for singly occupied orbital and 0 stands for unoccupied orbitals. Configuration Weight (%) orbital ordering: (σcho) (nb-fe 3dxy) (σeq) (πy) (πx) (σz) (π * y) (π * x) (σ * z) (σ * eq) (σ * CHO) (Fe-4dxy) (Fe-4dxz) (Fe-4dyz) S7

8 DFT Calculations 3 1 (0.00) 5 1 (18.6) Figure S7. Key geometrical parameters and relative spin-state energies (ΔEQ T, kcal/mol) obtained with DFT-B3LYP calculation for complex 1. Figure S8. Free energy change for the solvent (MeCN) dissociation process S8

9 Table S5. Computed thermodynamic parameters * (in kcal/mol) for the H-atom abstraction from CHD by complex 1 Species ΔEel ΔH ΔG CHD CHD RC RC TSσ Iσ TSπ Iπ * Energies are from B3LYP/def2-TZVPP and thermal corrections are from B3LYP/[def2-TZVP(-f) + def2-svp] Figure S9. Reaction free energy profile (ΔG/ΔH, in kcal/mol) for the first H-atom abstraction of DHA by complex 1. S9

10 Table S6. Computed thermodynamic parameters * (in kcal/mol) for the first H-abstraction from DHA by complex 1. Species ΔEel ΔH ΔG 3 FeO + DHA FeO + DHA RC RC TSσ Iσ TSπ Iπ TSπ Iπ * Energies are from B3LYP/def2-TZVPP and thermal corrections are from B3LYP/[def2-TZVP(-f) + def2-svp] Table S7. Key geometrical parameters for the reaction species involved in complex 1 and DHA calculated at DFT-B3LYP level of theory (atomic distances are in Å and angles are in degree). Species Fe O Fe NAc O H H C Fe O H O H O Fe Fe NA CAc C NAc 3 FeO FeO RC RC TSσ Iσ TSπ(a) Iπ TSπ Iπ S10

11 3 A (0.0) 5 A (2.8) Figure S10. Key geometrical parameters and relative spin-state energies (ΔEQ T, kcal/mol) obtained with DFT-B3LYP calculation for complex A. Table S8. Computed thermodynamic parameters * (in kcal/mol) for the first H-atom abstraction from CHD by complex A. Species ΔEel ΔH ΔG 3 A + CHD A + CHD RC RC TSσ Iσ TSπ Iπ TSπ Iπ TSσ Iσ S11

12 Table S9. Solvent (Ecorr/sol), non-thermal zero-point vibrational energy (ZPE) plus thermal energy (EZPE+T), thermal enthalpy (HT) and entropy term (T S) corrections obtained from DFT-B3LYP calculation. All energies are in hartree. Complex 1 Species Ecorr/sol EZPE+T HT T S CHD RC RC TSσ Iσ TSπ Iπ Complex 1 Species Ecorr/sol EZPE+T HT T S RC RC TSσ Iσ TSπ Iπ Complex A Species Ecorr/sol EZPE+T HT T S 3 A A RC RC TSσ Iσ TSπ Iπ TSπ Iπ TSσ Iσ S12

13 DFT-B3LYP optimized Cartesian coordinates of all the species involved (ordered and captioned following the Figure 4 of the main text) Fe O C C C C N N N N N N N N N C H C H C H H C H C H C H H C H H C H C H C H H C H C H C H H C H H C C H H S13

14 H Fe O C C C C N C N N N N N N N N C H C H C H H C H C H C H H C H H H C H C H H C H C H C H H C H H C C H H H S14

15 3 RC(1) Fe O C C C C N C N N C C C C N N C C C C N N C C C N N C C C C H H H H H H H H H H H H H H H H H H H H H H H C C S15

16 C C C C H H H H H H H H RC(1) Fe O C C C C N C N N C C C C N N C C C C N N C C C N N C C C C H H H H H H H H H H H H S16

17 H H H H H H H H H H H C C C C C C H H H H H H H H TSσ(1) Fe O H C C C C N C N H N C C C C N N C C C C N N C C C N N C S17

18 C C C H H H H H H H H H H H H H H H H H H H H H H C C C H C H H C C H H H H TSπ(1) Fe O C C C C N C N N C C C C N N C C S18

19 C C N N C C C N N C C C C H H H H H H H H H H H H H H H H H H H H H H H C C C C C C H H H H H H H H Iσ(1) Fe O H C C S19

20 C C N C N H N C C C C N N C C C C N N C C C N N C C C C H H H H H H H H H H H H H H H H H H H H H H C C C H C H H C C S20

21 H H H H Iπ(1) Fe O H C C C C C N C N N C C N N C C C C N N C C C N N C C C C C C H H H H H H H H H H H H H H H H H H H S21

22 H H H C C C C C H H H H H H H H Fe O C C C C N N N N N N N N C H C H C H H C H C H C H H C H H C H C H C H H S22

23 C H C H C H H C H H Fe O C C C C C N N N N N N N N C H C H C H H C H C H C H H C H H H C H C H H C H C H S23

24 C H H C H H RC(1 ) Fe O C C C C C N N C C N N C C C C N N C C C N N C C C C H H H H H H H H H H H H H H H H H H H H C C S24

25 C C C C H H H H H H H H RC(1 ) Fe O C C C C C N N C C N N C C C C N N C C C N N C C C C H H H H H H H H H H H H H H H H S25

26 H H H H C C C C C C H H H H H H H H TSσ(1 ) Fe O H C C C C C N N C C N N C C C C N N C C C N N C C C C H H H H H H H H H S26

27 H H H H H H H H H H H C C C H C H H C C H H H H TSπ(1 ) Fe O C C C C C N N C C N N C C C C N N C C C N N C C C C H H H H S27

Electronic Supplementary Material (ESI) for Chemical Science This journal is The Royal Society of Chemistry 2012

Electronic Supplementary Material (ESI) for Chemical Science This journal is The Royal Society of Chemistry 2012 Fig. S1 CASSCF (13,10) active space orbitals with Ru-Ru distance of 2.4 Å. Occupation numbers are on the left and energies in Hartrees are on the right of each orbital. The δ orbital is also included here,