University of Groningen
Biomimetic metal-mediated reactivity
Wegeberg, Christina
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Chapter 2
Summary
Oxidation chemistry performed by the iron-based complex of the ethylenediamine backboned ligand tpena (N,N,N’-tris(2-pyridylmethyl)ethylenediamine-N’-acetate) forms the basis of the work presented in this PhD thesis. This chapter summarizes the work performed in acetonitrile solutions with the terminal oxidants PhIO (Paper I and II), H2O2 (Paper IV), tBuOOH, cumylOOH
and m-CPBA (Paper V), the light-promoted reaction with O2 (Paper VI) as well as the work
performed in aqueous solutions with NaClO, m-CPBA and CAN in (Paper VIII). As a germane biomimetic system for iron non-heme O2 activating enzymes, the reactivity of the iron tpena
system as an oxidation catalyst is compared to related ethylenediamine backboned iron complexes (Paper VII and Paper VIII) to establish the influence of a carboxylate donor in the first coordination sphere around the iron centre. Additionally, as a spin-off of the work with PhIO, halogen-bonding in the gas-phase was established and investigated (Paper III). Paper I – Paper VIII are presented in complete detail in chapter 3 – chapter 10.
Chapter 2
2
The tpena System – A Germane Biomimetic System for
Non-Heme O
2Activating Enzymes
Tpena belongs to the family of ethylenediamine backboned ligands (Figure 15a). It has been used in a number of transition metal complexes (V,[98] Cr,[150] Mn,[151] Co,[152] Fe,[98,127,153] Cu[154]
and Zn[154]) owing to its remarkable structural flexibility, where tpena, e.g., can use its full
potential as a hexadentate ligand in the octahedral complexes [M(tpena)]+/2+ (M = Cr, Co, Fe, Zn.
Figure 15b) or act as a pentadentate ligand with one of the pyridyl arms non-coordinating allowing for another sixth exogenous ligand to complete an octahedral coordination environment as seen in the crystal structure of [Fe2O(Htpena)2](ClO4)4[127] or
[VO(Htpena)](ClO4)2[98] (Figure 15c). In relation to iron non-heme oxidation chemistry, the
incorporation of a cis carboxylate in the coordination sphere of the iron-based oxidants mimics the presence of an aspartate or glutamate in the active site of non-heme oxygen activation enzymes. Hereby it serves as a germane biomimetic model system for their redox activities and reactivity patterns.
(a)
(b) (c)
Figure 15. (a) Ethylenediamine backboned ligands and the R-groups investigated in this PhD thesis. The abbreviations
Htpena and HtpenO indicate protonation on one of the pyridyl units and deprotonation of the carboxylic acid and
alcohol units, respectively. (b) The cation [FeIII(tpena)]2+ (c) The cation [VIVO(Htpena)]2+. Hydrogen atoms are omitted
for clarity. Displacement ellipsoids are drawn at 50 % probability level. The μ-oxo-bridged diiron complex [FeIII
2O(Htpena)2](ClO4)4 serves as a starting point for the
oxidation chemistry explored and described in this Ph.D. thesis. Upon dissolving in acetonitrile, the μ-oxo complex equilibrates with two monomeric species fac-[Fe(tpena)]2+ and
mer-[Fe(tpena)]2+ (Figure 16). In Paper I and Paper VI this equilibrium and the speciation are
investigated with UV/vis absorption, EPR and Mössbauer spectroscopy both on bulk powdered samples obtained by diethyl ether diffusion and directly on acetonitrile solutions. It was found that the two diastereoisomers have different spin states (S = ½ vs. S = 5/
Summary
2
Figure 16. Equilibrium between [Fe2O(tpenaH)2]4+ and the two diastereoisomers of [Fe(tpena)]2+.
donor set in the first coordination sphere. Isolation of single crystals of fac-[Fe(tpena)]2+ (Figure
15b)and the obtained bond lengths indicate a low-spin electronic configuration for this ligand arrangement. The presence of a carboxylate group in the first coordination sphere significantly lowers the FeIII/FeII reduction potential for the diastereoisomers of [Fe(tpena)]2+ (0.02 V and 0.06
V vs. Fc/Fc+) compared to N5/N6 ethylenediamine backboned iron complexes (e.g. 0.40 V vs.
Fc/Fc+ for [Fe(tpen)]2+) as well as previously reported iron non-heme complexes without this
group, hence stabilizing an iron(III) oxidation state rather than an iron(II) oxidation state.[41,55,146]
The crystal structure of a trapped iron-tpena-based oxidant [{Fe(OIPh)(tpena)}2](ClO4)4 was
published in 2012 by the McKenzie group.[127] In Paper I and Paper II this novel species and its
properties are explored in more detail. Paper I focuses on the potency of [Fe(tpena)]2+ as a
homogenous catalyst in selective sulfoxidation and epoxidation using the oxidants PhIO and methyl-morpholine-N-oxide, which demonstrates that the catalytic system is more effective when PhIO is used as the terminal oxidant. The high selectivity of the system is inconsistent with the generation of radicals i.e. [FeIVO(Htpena)]2+ and PhI•, despite these ions being detected in gas
phase studies on [{Fe(OIPh)(tpena)}2](ClO4)4. Kinetic experiments with substituted substrates
(Paper I) and characterization with XAS (Paper II) indicate that one of [{Fe(OIPh)(tpena)}2]4+,
[Fe(OIPh)(tpena)]2+ or an iron(V)oxo species (generated through heterolytic cleavage of the
FeO-IPh bond) is the active oxidant (Figure 17). An ion corresponding to [FeVO(tpena)]2+ is observed
in the gas-phase, but the lack of reactivity towards oxidizable gas-phase substrates suggests that the ion is better formulated as an iron(III) complex of oxygenated tpena. Iodine L3-edge displays
a reduction of the iodine atom (+1.6) in [{Fe(OIPh)(tpena)}2]4+ compared to free [PhIO]n (+3), which indicate that the halogen bonding demonstrated in the solid state crucial for the isolation, also plays an important role in the catalytic reactivity of [Fe(OIPh)(tpena)]2+ in the solution state.
Additionally, Paper III establishes the presence of halogen bonding in the gas-phase important for large gas-phase associations. PhIO2 was used as the prototype halogen-bonding
donor-acceptor analyte, and clusters with supramolecular masses up to 7147 Da were detected ([Na3(PhIO)30)]3+).
The activation of peroxides by [Fe(tpena)]2+ is examined in Paper IV and Paper V.
[Fe(OOR)(Htpena)]2+ (R = H, tBu, cumyl, m-CPBA) and [Fe(OO)(Htpena)]+ species are
characterized spectroscopically in acetonitrile solutions. The iron(III)-hydroperoxo and -alkylperoxo species undergo rapid O-O bond homolysis resulting in the generation of
[FeIVO(Htpena)]2+ and RO• radicals (Figure 17). [FeIVO(Htpena)]2+ is detected spectroscopically
when tBuOOH, cumylOOH and m-CPBA are used, but not in the presence of H
2O2. Iron tpena
Chapter 2
2
qualitative and quantitative detection of O2. [FeIVO(Htpena)]2+ is proposed to be the active
species catalysing this reaction, however – and importantly – the reactivity of [FeIVO(Htpena)]2+
can be guided towards C-H oxidation by addition of excess amounts of substrate. In the absence of an external substrate or low concentration of H2O2, the generation of hydroxyl radicals causes
ligand degradation, when H2O2 is used as terminal oxidant. Generation of the less reactive
organic alkoxyl radical for the use of alkyl hydroperoxides contrasts these observations, since cyclability of the metal-based oxidants and O2 production were demonstrated.
Figure 17. Tuning performed in this PhD project on ethylenediamine backboned non-heme iron complexes in relation
to oxidation chemistry. Tuning in reactivity between the paradigms of HAT (FeIV=O) and OAT (FeIIIO-X and FeV=O) is
demonstrated by the change of oxidant (Paper I, II, IV, V and VIII) and/or ligand (Paper VII and Paper VIII). X = OH,
OtBu, Ocumyl, m-CBA, Cl, NM(O). L = ethylenediamine backboned ligand:
N-R-N,N’,N’-tris(2-pyridylmethyl)ethane-1,2-diamine, (R = CH3 (metpen), CH2CH3 (ettpen), CH2C6H5 (bztpen), CH2C6H4N (tpen), CH2CH2OH (tpenOH) and CH2COOH
(tpenaH)).
In the absence of an oxidant, [Fe(tpena)]2+ is not stable in acetonitrile solutions under ambient
conditions, and the complex undergoes irreversible, light-promoted O2-dependent
N-deglycination to generate an iron(II) complex with a total mass loss equivalent to C2H3O2 from
tpena. With the use of combined time-dependent spectroscopy, product detection and DFT calculations Paper VI examines the degradation mechanism. It is shown to be a two-step mechanism: irradiation of [Fe(tpena)]2+ with nearUV-light causes immediate decarboxylation to
form a transient iron(II) species which can activate dioxygen, which subsequently undergoes rearrangement to generate the crystallographically characterized product. The carbon sources for the glycyl arm are experimentally identified as CO2 and formaldehyde.
Paper VII and Paper VIII examine the scope of ethylenediamine backboned iron complexes in the activation of oxidants as well as the reactivity of the subsequently formed metal-based oxidants towards C-H bonds. Iron(III)hydroperoxides in organic solvents generated with H2O2
(Paper VII) and iron(IV)oxo species in water generated with CAN/H2O, ClO- or m-CPBA (Paper
VIII) were spectroscopically characterized. The catalytically active oxidants were assigned to iron(IV)oxo species formed through either homolytic FeO-X bond cleavage or directly with one electron oxidants. Paper VII demonstrates that the potency of the iron complexes in H2O2
activation towards oxidation of cyclohexanol and cyclooctene can be correlated with the FeII/FeIII
reduction potentials of the iron complexes. Hence the FeII/FeIII reduction potential of the catalyst
gives an indication of the oxidative power of the catalytic active iron(IV)oxo species. Paper VIII shows that the λmax of the iron(IV)oxo species correlates with the efficiency for these species in
HAT reactions: the more red-shifted the maximum absorption band is, the greater the second-order rate constants, k2, can be obtained. The catalysts [Fe(tpena)]2+ and [Fe(tpenO)]2+ (both
Summary
2
N5O ligands) perform best in both studies presented in Paper VII and Paper VIII. The FeII/FeIII
reduction potential of [Fe(tpenO)]2+ (in MeCN) is located between that of [Fe(tpena)]2+ and
[Fe(tpen)]2+: the easier accessibility of the iron(III) oxidation states for [Fe(tpena)]2+ and
[Fe(tpenO)]2+ is believed to be crucial for the higher reactivity observed (e.g. peroxide
disproportionation and water oxidation). The oxidative power of [FeIVO(Htpena)]2+/[FeIVO(tpena)]+ and [FeIVO(HtpenO)]2+ is remarkable compared to previous
reports on iron(IV)oxo species (mainly N5 or N6), and importantly these observations are made in aqueous solutions.
Ultimately, the work presented in this PhD thesis shows that the presence of a carboxylate in the first coordination sphere of non-heme iron(IV)oxo, iron(III)hydroperoxo, iron(III)alkylperoxo and iron(III)iodosyl species induces significantly different reactivity patterns compared to the last three decades of reports on non-heme iron complexes mainly based on N-only ligands. [Fe(tpena)]2+-catalysed substrate oxidations can be guided towards either HAT or OAT
mechanisms (Figure 18) simply by the choice of oxidant and reaction conditions hereby giving the iron-tpena system a remarkable diversity. Properties such as structural flexibility of the ligand, geometrical and spin-state flexibility of the iron centre as well as the nature of the FeO-X bond (Figure 17) are crucial for the switch between the two paradigms of reaction pathways. When peroxides are used as oxidants, the FeO-X bond is highly labile exposing the reactive and active oxidant in HAT reactions: [FeIVO(Htpena)]2+. Observations of H
2O2, alkyl and acyl
disproportionation and higher reactivity in HAT reactions is ascribed to larger oxyl radical character on [FeIVO(Htpena)]2+ compared to other ethylenediamine iron(IV)oxo species. A higher
stability of the FeO-X bond, as is the case for PhIO, on the other hand guides the reactivity to an OAT-based oxidation pathway. Understanding the importance of this switch in reactivity as well as the generation of active oxidants by a one electron donor (hereby avoiding the release of free radicals) are key aspects for further development of [Fe(tpena)]2+ as a homogenous oxidation
catalyst in both organic and aqueous solutions.
Figure 18. The choice of oxidant guides the reactivity of the iron-tpena system towards either HAT- or OAT-based
Bibliography
[1] R. E. Stenkamp, Chem. Rev. 1994, 94, 715–726.
[2] M. A. Holmes, I. Le Trong, S. Turley, L. C. Sieker, R. E. Stenkamp, J. Mol. Biol. 1991, 218, 583–593. [3] P. Nordlund, B. M. Sjöberg, H. Eklund, Nature 1990, 345, 593–598.
[4] A. C. Rosenzweig, C. A. Frederick, S. J. Lippard, P. Nordlund, Nature 1993, 366, 537–543. [5] E. G. Kovaleva, J. D. Lipscomb, Nat. Chem. Biol. 2008, 4, 186–193.
[6] E. L. Hegg, L. Que, Eur. J. Biochem. 1997, 250, 625–629.
[7] K. D. Koehntop, J. P. Emerson, L. Que, J. Biol. Inorg. Chem. 2005, 10, 87–93.
[8] P. K. Grzyska, E. H. Appelman, R. P. Hausinger, D. A. Proshlyakov, Proc. Natl. Acad. Sci. USA 2010,
107, 3982–3987.
[9] Y. Wang, J. Li, A. Liu, J. Biol. Inorg. Chem. 2017, 22, 395–405.
[10] M. Swart, M. Costas, Eds., Spin States in Biochemistry and Inorganic Chemistry, John Wiley & Sons, Ltd, Oxford, UK, 2015.
[11] F. Neese, Coord. Chem. Rev. 2009, 253, 526–563.
[12] J. C. Price, E. W. Barr, B. Tirupati, J. M. Bollinger, C. Krebs, Biochemistry 2003, 42, 7497–7508. [13] P. J. Riggs-Gelasco, J. C. Price, R. B. Guyer, J. H. Brehm, E. W. Barr, J. M. Bollinger, C. Krebs, J. Am.
Chem. Soc. 2004, 126, 8108–8109.
[14] D. A. Proshlyakov, T. F. Henshaw, G. R. Monterosso, M. J. Ryle, R. P. Hausinger, J. Am. Chem. Soc. 2004, 126, 1022–1023.
[15] G. Schenk, M. Y. M. Pau, E. I. Solomon, J. Am. Chem. Soc. 2004, 126, 505–515.
[16] M. M. Mbughuni, M. Chakrabarti, J. A. Hayden, E. L. Bominaar, M. P. Hendrich, E. Münck, J. D. Lipscomb, Proc. Natl. Acad. Sci. USA 2010, 107, 16788–16793.
[17] L. Shu, Y. M. Chiou, A. M. Orville, M. A. Miller, J. D. Lipscomb, L. Que, Biochemistry 1995, 34, 6649–6659.
[18] E. L. Spence, G. J. Langley, T. D. H. Bugg, J. Am. Chem. Soc. 1996, 118, 8336–8343. [19] E. G. Kovaleva, J. D. Lipscomb, Science 2007, 316, 453–457.
[20] H. Umezawa, K. Maeda, T. Takeuchi, Y. Okami, J. Antibiot. 1966, 19, 200–209. [21] J. Chen, J. Stubbe, Nat. Rev. Cancer 2005, 5, 102–112.
[22] Y. Sugiura, J. Am. Chem. Soc. 1980, 102, 5208–5215.
Bibliography
[24] A. Kittaka, Y. Sugano, M. Otsuka, M. Ohno, Tetrahedron 1988, 44, 2811–2820. [25] J. W. Sam, X.-J. Tang, J. Peisach, J. Am. Chem. Soc. 1994, 116, 5250–5256. [26] Y. Sugiura, T. Kikuchi, J. Antibiot. 1978, 31, 1310–1312.
[27] R. M. Burger, J. Peisach, S. B. Horwitz, J. Biol. Chem. 1981, 256, 11636–11644.
[28] F. Neese, J. M. Zaleski, K. Loeb Zaleski, E. I. Solomon, J. Am. Chem. Soc. 2000, 122, 11703–11724. [29] K. D. Goodwin, M. A. Lewis, E. C. Long, M. M. Georgiadis, Proc. Natl. Acad. Sci. USA 2008, 105,
5052–5056.
[30] A. Kittaka, Y. Sugano, M. Otsuka, M. Ohno, Y. Sugiura, H. Umezawa, Tetrahedron Lett. 1986, 27, 3631–3634.
[31] Y. Sugano, A. Kittaka, M. Otsuka, M. Ohno, Y. Sugiura, H. Umezawa, Tetrahedron Lett. 1986, 27, 3635–3638.
[32] A. Kittaka, Y. Sugano, M. Otsuka, M. Ohno, Tetrahedron 1988, 44, 2821–2833.
[33] M. Lubben, A. Meetsma, E. C. Wilkinson, B. Feringa, L. Que, Angew. Chem. Int. Ed. Engl. 1995, 34, 1512–1514.
[34] R. Y. N. Ho, G. Roelfes, B. L. Feringa, L. Que, J. Am. Chem. Soc. 1999, 121, 264–265.
[35] G. Roelfes, V. Vrajmasu, K. Chen, R. Y. N. Ho, J.-U. Rohde, C. Zondervan, R. M. La Crois, E. P. Schudde, M. Lutz, A. L. Spek, R. Hage, B. L. Feringa, E. Münck, L. Que, Inorg. Chem. 2003, 42, 2639–2653.
[36] C. Kim, K. Chen, J. Kim, L. Que, J. Am. Chem. Soc. 1997, 119, 5964–5965.
[37] A. J. Simaan, S. Döpner, F. Banse, S. Bourcier, G. Bouchoux, A. Boussac, P. Hildebrandt, J.-J. Girerd, Eur. J. Inorg. Chem. 2000, 2000, 1627–1633.
[38] I. Bernal, I. M. Jensen, K. B. Jensen, C. J. McKenzie, H. Toftlund, J.-P. Tuchagues, J. Chem. Soc.,
Dalton Trans. 1995, 3667–3675.
[39] K. B. Jensen, C. J. McKenzie, L. P. Nielsen, J. Zacho Pedersen, H. M. Svendsen, Chem. Commun. 1999, 1313–1314.
[40] O. Horner, C. Jeandey, J.-L. Oddou, P. Bonville, C. McKenzie, J.-M. Latour, Eur. J. Inorg. Chem. 2002, 2002, 3278–3283.
[41] C. Wegeberg, F. R. Lauritsen, C. Frandsen, S. Mørup, W. R. Browne, C. J. McKenzie, Chem. Eur. J. 2018, 24, 5134–5145.
[42] S. Ménage, E. C. Wilkinson, L. Que, M. Fontecave, Angew. Chem. Int. Ed. Engl. 1995, 34, 203–205. [43] J. Kim, E. Larka, E. C. Wilkinson, L. Que, Angew. Chem. Int. Ed. Engl. 1995, 34, 2048–2051. [44] Y. Zang, J. Kim, Y. Dong, E. C. Wilkinson, E. H. Appelman, L. Que, J. Am. Chem. Soc. 1997, 119,
[45] M. P. Jensen, A. M. I. Payeras, A. T. Fiedler, M. Costas, J. Kaizer, A. Stubna, E. Münck, L. Que,
Inorg. Chem. 2007, 46, 2398–2408.
[46] M. P. Jensen, M. Costas, R. Y. N. Ho, J. Kaizer, A. Mairata i Payeras, E. Münck, L. Que, J.-U. Rohde, A. Stubna, J. Am. Chem. Soc. 2005, 127, 10512–10525.
[47] F. Namuswe, G. D. Kasper, A. A. N. Sarjeant, T. Hayashi, C. M. Krest, M. T. Green, P. Moënne-Loccoz, D. P. Goldberg, J. Am. Chem. Soc. 2008, 130, 14189–14200.
[48] M. Costas, M. P. Mehn, M. P. Jensen, L. Que, Chem. Rev. 2004, 104, 939–986. [49] W. Nam, Acc. Chem. Res. 2015, 48, 2415–2423.
[50] G. Anderegg, F. Wenk, Helv. Chim. Acta 1967, 50, 2330–2332.
[51] R. A. Leising, R. E. Norman, L. Que, Inorg. Chem. 1990, 29, 2553–2555.
[52] J.-U. Rohde, J.-H. In, M. H. Lim, W. W. Brennessel, M. R. Bukowski, A. Stubna, E. Münck, W. Nam, L. Que, Science 2003, 299, 1037–1039.
[53] K. Chen, L. Q. Jr., Chem. Commun. 1999, 1375–1376.
[54] C. A. Grapperhaus, B. Mienert, E. Bill, T. Weyhermüller, K. Wieghardt, Inorg. Chem. 2000, 39, 5306–5317.
[55] A. Hazell, C. J. McKenzie, L. P. Nielsen, S. Schindler, M. Weitzer, J. Chem. Soc., Dalton Trans. 2002, 310.
[56] A. Nielsen, F. B. Larsen, A. D. Bond, C. J. McKenzie, Angew. Chem. Int. Ed. Engl. 2006, 45, 1602– 1606.
[57] S. Gosiewska, E. E. van Faassen, H. P. Permentier, A. P. Bruins, G. van Koten, R. J. M. K. Gebbink,
Dalton Trans. 2007, 3365–3368.
[58] I. Monte Pérez, X. Engelmann, Y.-M. Lee, M. Yoo, E. Kumaran, E. R. Farquhar, E. Bill, J. England, W. Nam, M. Swart, et al., Angew. Chem. Int. Ed. Engl. 2017, 56, 14384–14388.
[59] A. R. McDonald, M. R. Bukowski, E. R. Farquhar, T. A. Jackson, K. D. Koehntop, M. S. Seo, R. F. De Hont, A. Stubna, J. A. Halfen, E. Münck, et al., J. Am. Chem. Soc. 2010, 132, 17118–17129. [60] F. Namuswe, T. Hayashi, Y. Jiang, G. D. Kasper, A. A. N. Sarjeant, P. Moënne-Loccoz, D. P.
Goldberg, J. Am. Chem. Soc. 2010, 132, 157–167.
[61] Y. Zang, T. E. Elgren, Y. Dong, L. Que, J. Am. Chem. Soc. 1993, 115, 811–813.
[62] F. Li, K. K. Meier, M. A. Cranswick, M. Chakrabarti, K. M. Van Heuvelen, E. Münck, L. Que, J. Am.
Chem. Soc. 2011, 133, 7256–7259.
[63] J. Cho, S. Jeon, S. A. Wilson, L. V. Liu, E. A. Kang, J. J. Braymer, M. H. Lim, B. Hedman, K. O. Hodgson, J. S. Valentine, E. I. Solomon, W. Nam, Nature 2011, 478, 502–505.
[64] N. Lehnert, R. Y. Ho, L. Que, E. I. Solomon, J. Am. Chem. Soc. 2001, 123, 12802–12816.
[65] A. Wada, S. Ogo, S. Nagatomo, T. Kitagawa, Y. Watanabe, K. Jitsukawa, H. Masuda, Inorg. Chem. 2002, 41, 616–618.
Bibliography
[66] A. Wada, S. Ogo, Y. Watanabe, M. Mukai, T. Kitagawa, K. Jitsukawa, H. Masuda, H. Einaga, Inorg.
Chem. 1999, 38, 3592–3593.
[67] K. P. Bryliakov, E. P. Talsi, Coord Chem Rev 2014, 276, 73–96.
[68] N. Lehnert, R. Y. Ho, L. Que, E. I. Solomon, J. Am. Chem. Soc. 2001, 123, 8271–8290.
[69] K. Hashimoto, S. Nagatomo, S. Fujinami, H. Furutachi, S. Ogo, M. Suzuki, A. Uehara, Y. Maeda, Y. Watanabe, T. Kitagawa, Angew. Chem. Int. Ed. Engl. 2002, 41, 1202–1205.
[70] S. Hong, K. D. Sutherlin, J. Park, E. Kwon, M. A. Siegler, E. I. Solomon, W. Nam, Nat. Commun. 2014, 5, 5440.
[71] T. Kishima, T. Matsumoto, H. Nakai, S. Hayami, T. Ohta, S. Ogo, Angew. Chem. Int. Ed. Engl. 2016,
55, 724–727.
[72] R. A. Leising, Y. Zang, L. Que, J. Am. Chem. Soc. 1991, 113, 8555–8557.
[73] T. Kojima, R. A. Leising, S. Yan, L. Que, J. Am. Chem. Soc. 1993, 115, 11328–11335.
[74] R. A. Leising, B. A. Brennan, L. Que, B. G. Fox, E. Munck, J. Am. Chem. Soc. 1991, 113, 3988–3990. [75] A. P. Sobolev, D. E. Babushkin, E. P. Talsi, J. Mol. Catal. A: Chem 2000, 159, 233–245.
[76] J. Kaizer, M. Costas, L. Que, Angew. Chem. Int. Ed. Engl. 2003, 42, 3671–3673.
[77] M. H. Lim, J.-U. Rohde, A. Stubna, M. R. Bukowski, M. Costas, R. Y. N. Ho, E. Munck, W. Nam, L. Que, Proc. Natl. Acad. Sci. USA 2003, 100, 3665–3670.
[78] S. Hong, Y.-M. Lee, K.-B. Cho, M. S. Seo, D. Song, J. Yoon, R. Garcia-Serres, M. Clémancey, T. Ogura, W. Shin, J. M. Latour, W. Nam, Chem. Sci. 2014, 5, 156–162.
[79] F. Neese, E. I. Solomon, J. Am. Chem. Soc. 1998, 120, 12829–12848.
[80] J. Annaraj, Y. Suh, M. S. Seo, S. O. Kim, W. Nam, Chem. Commun. 2005, 4529.
[81] A. J. Simaan, F. Banse, P. Mialane, A. Boussac, S. Un, T. Kargar-Grisel, G. Bouchoux, J.-J. Girerd,
Eur. J. Inorg. Chem. 1999, 1999, 993–996.
[82] A. J. Simaan, F. Banse, J. J. Girerd, K. Wieghardt, E. Bill, Inorg. Chem. 2001, 40, 6538–6540. [83] O. Horner, C. Jeandey, J.-L. Oddou, P. Bonville, J.-M. Latour, Eur. J. Inorg. Chem. 2002, 2002,
1186–1189.
[84] S. Ahmad, J. D. McCallum, A. K. Shiemke, E. H. Appelman, T. M. Loehr, J. Sanders-Loehr, Inorg.
Chem. 1988, 27, 2230–2233.
[85] A. R. McDonald, L. Que, Coord Chem Rev 2013, 257, 414–428.
[86] T. A. Jackson, J.-U. Rohde, M. S. Seo, C. V. Sastri, R. DeHont, A. Stubna, T. Ohta, T. Kitagawa, E. Münck, W. Nam, et al., J. Am. Chem. Soc. 2008, 130, 12394–12407.
[87] C. V. Sastri, J. Lee, K. Oh, Y. J. Lee, J. Lee, T. A. Jackson, K. Ray, H. Hirao, W. Shin, J. A. Halfen, et al.,
[88] J.-U. Rohde, A. Stubna, E. L. Bominaar, E. Münck, W. Nam, L. Que, Inorg. Chem. 2006, 45, 6435– 6445.
[89] E. J. Klinker, J. Kaizer, W. W. Brennessel, N. L. Woodrum, C. J. Cramer, L. Que, Angew. Chem. Int.
Ed. Engl. 2005, 44, 3690–3694.
[90] J. Kaizer, E. J. Klinker, N. Y. Oh, J.-U. Rohde, W. J. Song, A. Stubna, J. Kim, E. Münck, W. Nam, L. Que, J. Am. Chem. Soc. 2004, 126, 472–473.
[91] V. Balland, M.-F. Charlot, F. Banse, J.-J. Girerd, T. Mattioli, E. Bill, J.-F. Bartoli, P. Battioni, D. Mansuy, Eur. J. Inorg. Chem. 2004, 2004, 301–308.
[92] M. Martinho, F. Banse, J.-F. Bartoli, T. A. Mattioli, P. Battioni, O. Horner, S. Bourcier, J.-J. Girerd,
Inorg. Chem. 2005, 44, 9592–9596.
[93] O. Pestovsky, S. Stoian, E. L. Bominaar, X. Shan, E. Münck, L. Que, A. Bakac, Angew. Chem. Int. Ed.
Engl. 2005, 44, 6871–6874.
[94] J. England, M. Martinho, E. R. Farquhar, J. R. Frisch, E. L. Bominaar, E. Münck, L. Que, Angew.
Chem. Int. Ed. Engl. 2009, 48, 3622–3626.
[95] D. C. Lacy, R. Gupta, K. L. Stone, J. Greaves, J. W. Ziller, M. P. Hendrich, A. S. Borovik, J. Am. Chem.
Soc. 2010, 132, 12188–12190.
[96] J. P. Bigi, W. H. Harman, B. Lassalle-Kaiser, D. M. Robles, T. A. Stich, J. Yano, R. D. Britt, C. J. Chang,
J. Am. Chem. Soc. 2012, 134, 1536–1542.
[97] C. B. Bell, S. D. Wong, Y. Xiao, E. J. Klinker, A. L. Tenderholt, M. C. Smith, J.-U. Rohde, L. Que, S. P. Cramer, E. I. Solomon, Angew. Chem. Int. Ed. Engl. 2008, 47, 9071–9074.
[98] M. S. Vad, A. Lennartson, A. Nielsen, J. Harmer, J. E. McGrady, C. Frandsen, S. Mørup, C. J. McKenzie, Chem. Commun. 2012, 48, 10880–10882.
[99] A. Chanda, X. Shan, M. Chakrabarti, W. C. Ellis, D. L. Popescu, F. Tiago de Oliveira, D. Wang, L. Que, T. J. Collins, E. Münck, E. L. Bominaar, Inorg. Chem. 2008, 47, 3669–3678.
[100] L. Bernasconi, M. J. Louwerse, E. J. Baerends, Eur. J. Inorg. Chem. 2007, 2007, 3023–3033. [101] A. Decker, J.-U. Rohde, E. J. Klinker, S. D. Wong, L. Que, E. I. Solomon, J. Am. Chem. Soc. 2007,
129, 15983–15996.
[102] N. Y. Lee, D. Mandal, S. H. Bae, M. S. Seo, Y.-M. Lee, S. Shaik, K.-B. Cho, W. Nam, Chem. Sci. 2017,
8, 5460–5467.
[103] C. E. MacBeth, A. P. Golombek, V. G. Young, C. Yang, K. Kuczera, M. P. Hendrich, A. S. Borovik,
Science 2000, 289, 938–941.
[104] E. A. Hill, A. C. Weitz, E. Onderko, A. Romero-Rivera, Y. Guo, M. Swart, E. L. Bominaar, M. T. Green, M. P. Hendrich, D. C. Lacy, et al., J. Am. Chem. Soc. 2016, 138, 13143–13146.
[105] W. Rasheed, A. Draksharapu, S. Banerjee, V. G. Young, R. Fan, Y. Guo, M. Ozerov, J. Nehrkorn, J. Krzystek, J. Telser, L. Que, Angew. Chem. Int. Ed. Engl. 2018, 57, 9387-9391
Bibliography
[107] A. Ghosh, F. Tiago de Oliveira, T. Yano, T. Nishioka, E. S. Beach, I. Kinoshita, E. Münck, A. D. Ryabov, C. P. Horwitz, T. J. Collins, J. Am. Chem. Soc. 2005, 127, 2505–2513.
[108] D.-L. Popescu, M. Vrabel, A. Brausam, P. Madsen, G. Lente, I. Fabian, A. D. Ryabov, R. van Eldik, T. J. Collins, Inorg. Chem. 2010, 49, 11439–11448.
[109] M. R. Mills, A. C. Weitz, M. P. Hendrich, A. D. Ryabov, T. J. Collins, J. Am. Chem. Soc. 2016, 138, 13866 − 13869.
[110] A. Draksharapu, W. Rasheed, J. E. M. N. Klein, L. Que, Angew. Chem. Int. Ed. Engl. 2017, 56, 9091– 9095.
[111] D. P. de Sousa, C. J. Miller, Y. Chang, T. D. Waite, C. J. McKenzie, Inorg. Chem. 2017, 56, 14936– 14947.
[112] T. Chantarojsiri, Y. Sun, J. R. Long, C. J. Chang, Inorg. Chem. 2015, 54, 5879–5887. [113] T. J. Collins, Acc. Chem. Res. 2002, 35, 782–790.
[114] R. Mas-Ballesté, L. Que, J. Am. Chem. Soc. 2007, 129, 15964–15972.
[115] F. Tiago de Oliveira, A. Chanda, D. Banerjee, X. Shan, S. Mondal, L. Que, E. L. Bominaar, E. Münck, T. J. Collins, Science 2007, 315, 835–838.
[116] M. Ghosh, K. K. Singh, C. Panda, A. Weitz, M. P. Hendrich, T. J. Collins, B. B. Dhar, S. Sen Gupta, J.
Am. Chem. Soc. 2014, 136, 9524–9527.
[117] K. K. Singh, M. k Tiwari, M. Ghosh, C. Panda, A. Weitz, M. P. Hendrich, B. B. Dhar, K. Vanka, S. Sen Gupta, Inorg. Chem. 2015, 54, 1535–1542.
[118] S. Pattanayak, A. J. Jasniewski, A. Rana, A. Draksharapu, K. K. Singh, A. Weitz, M. Hendrich, L. Que, A. Dey, S. Sen Gupta, Inorg. Chem. 2017, 56, 6352–6361.
[119] K. M. Van Heuvelen, A. T. Fiedler, X. Shan, R. F. De Hont, K. K. Meier, E. L. Bominaar, E. Münck, L. Que, Proc. Natl. Acad. Sci. USA 2012, 109, 11933–11938.
[120] J. Serrano-Plana, W. N. Oloo, L. Acosta-Rueda, K. K. Meier, B. Verdejo, E. García-España, M. G. Basallote, E. Münck, L. Que, A. Company, et al., J. Am. Chem. Soc. 2015, 137, 15833–15842. [121] R. Fan, J. Serrano-Plana, W. N. Oloo, A. Draksharapu, E. Delgado-Pinar, A. Company, V.
Martin-Diaconescu, M. Borrell, J. Lloret-Fillol, E. García-España, Y. Guo, E. L. Bominaar, J. Am. Chem. Soc. 2018, 140, 3916–3928.
[122] O. Y. Lyakin, K. P. Bryliakov, G. J. P. Britovsek, E. P. Talsi, J. Am. Chem. Soc. 2009, 131, 10798– 10799.
[123] O. Y. Lyakin, R. V. Ottenbacher, K. P. Bryliakov, E. P. Talsi, ACS Catal. 2012, 2, 1196–1202. [124] O. Y. Lyakin, A. M. Zima, D. G. Samsonenko, K. P. Bryliakov, E. P. Talsi, ACS Catal. 2015, 5, 2702–
2707.
[125] W. N. Oloo, K. K. Meier, Y. Wang, S. Shaik, E. Münck, L. Que, Nat Commun 2014, 5, 3046. [126] Y. Wang, D. Janardanan, D. Usharani, K. Han, L. Que, S. Shaik, ACS Catal. 2013, 3, 1334–1341.
[127] A. Lennartson, C. J. McKenzie, Angew. Chem. Int. Ed. Engl. 2012, 51, 6767–6770.
[128] Y. Kang, X.-X. Li, K.-B. Cho, W. Sun, C. Xia, W. Nam, Y. Wang, J. Am. Chem. Soc. 2017, 139, 7444– 7447.
[129] S. Hong, B. Wang, M. S. Seo, Y.-M. Lee, M. J. Kim, H. R. Kim, T. Ogura, R. Garcia-Serres, M. Clémancey, J.-M. Latour, W. Nam, Angew. Chem. Int. Ed. Engl. 2014, 53, 6388–6392. [130] B. Wang, Y.-M. Lee, M. S. Seo, W. Nam, Angew. Chem. Int. Ed. Engl. 2015, 54, 11740–11744. [131] W. C. Bray, M. H. Gorin, J. Am. Chem. Soc. 1932, 54, 2124–2125.
[132] J. T. Groves, M. Van der Puy, J. Am. Chem. Soc. 1974, 96, 5274–5275. [133] J. T. Groves, M. Van der Puy, J. Am. Chem. Soc. 1976, 98, 5290–5297. [134] H. Sugimoto, D. T. Sawyer, J. Am. Chem. Soc. 1984, 106, 4283–4285. [135] H. Sugimoto, D. T. Sawyer, J. Am. Chem. Soc. 1985, 107, 5712–5716. [136] H. Sugimoto, D. T. Sawyer, J. Org. Chem. 1985, 50, 1784–1786. [137] F. Haber, J. Weiss, Proc. Math.Phys. Eng. Sci. 1934, 147, 332–351.
[138] P. A. MacFaul, I. W. C. E. Arends, K. U. Ingold, D. D. M. Wayner, J. Chem. Soc., Perkin Trans. 2 1997, 135–146.
[139] J. Kim, R. G. Harrison, C. Kim, L. Que, J. Am. Chem. Soc. 1996, 118, 4373–4379. [140] G. A. Russell, J. Am. Chem. Soc. 1957, 79, 3871–3877.
[141] J. A. Howard, K. U. Ingold, J. Am. Chem. Soc. 1968, 90, 1056–1058.
[142] G. Roelfes, M. Lubben, R. Hage, L. Que, Jr., B. L. Feringa, Chem. Eur. J. 2000, 6, 2152–2159. [143] M. J. Park, J. Lee, Y. Suh, J. Kim, W. Nam, J. Am. Chem. Soc. 2006, 128, 2630–2634.
[144] M. S. Seo, T. Kamachi, T. Kouno, K. Murata, M. J. Park, K. Yoshizawa, W. Nam, Angew. Chem. Int.
Ed. Engl. 2007, 46, 2291–2294.
[145] A. S. Faponle, M. G. Quesne, C. V. Sastri, F. Banse, S. P. de Visser, Chem. Eur. J. 2015, 21, 1221– 1236.
[146] G. Olivo, O. Cussó, M. Borrell, M. Costas, J. Biol. Inorg. Chem. 2017, 22, 425–452.
[147] O. Cussó, I. Garcia-Bosch, X. Ribas, J. Lloret-Fillol, M. Costas, J. Am. Chem. Soc. 2013, 135, 14871– 14878.
[148] J. O. Bigelow, J. England, J. E. M. N. Klein, E. R. Farquhar, J. R. Frisch, M. Martinho, D. Mandal, E. Münck, S. Shaik, L. Que, Inorg. Chem. 2017, 56, 3287–3301.
[149] J. Chen, A. Draksharapu, E. Harvey, W. Rasheed, L. Que, W. R. Browne, Chem. Commun. 2017, 53, 12357–12360.
[150] D. P. de Sousa, J. O. Bigelow, J. Sundberg, L. Que, C. J. McKenzie, Chem. Commun. 2015, 51, 2802– 2805.
Bibliography
[151] C. Deville, M. Finsel, D. P. de Sousa, B. Szafranowska, J. Behnken, S. Svane, A. D. Bond, R. K. Seidler-Egdal, C. J. McKenzie, Eur. J. Inorg. Chem. 2015, 2015, 3543–3549.
[152] M. S. Vad, A. Nielsen, A. Lennartson, A. D. Bond, J. E. McGrady, C. J. McKenzie, Dalton Trans. 2011, 40, 10698–10707.
[153] D. P. de Sousa, C. Wegeberg, M. S. Vad, S. Mørup, C. Frandsen, W. A. Donald, C. J. McKenzie,
Chem. Eur. J. 2016, 22, 3810–3820.
