Publikationsliste
[2022][2021][2020] [2019] [2018] [2017] [2016] [2015] [2014] [2013] [2012] [2011] [2010] [2008] [2007][2006][2005] [2004] [2003]
- "Modelling the coordination environment in alpha-ketoglutarate dependent oxygenases - a comparative study on the effect of N- vs. O-ligation"
K. Warm, D. Kass, M. Haumann, H. Dau, K. Ray, Z. Anorg. Allg. Chem., 2022, DOI: 10.1002/zaac.202100310.
- "The influence of secondary interactions on the [Ni(O2)]+ mediated aldehyde oxidation reactions"
B. Battistella, K. Warm, B. Cula, B. Lu, P. Hildebrandt, U. Kuhlmann, H. Dau, S. Mebs, K. Ray, Journal of Inorganic Biochemistry, 2022, DOI: 10.1016/j.jinorgbio.2021.111668.
- "Formation of cobalt-oxygen intermediates by dioxygen activation at a mononuclear nonheme cobalt(II) center"
D. D. Malik, A. Chandra, M. S. Seo, Y.-M. Lee, E. R. Farquhar, S. Mebs, H. Dau, K. Ray and W. Nam, Dalton Trans. 2021, DOI: 10.1039/D1DT01996A.
- "Spectroscopic Characterization of a reactive [Cu2(µ-OH)2] intermediate in Cu/TEMPO catalyzed aerobic alcohol oxidation reaction"
K. Warm, G. Tripodi, E. Andris, S. Mebs, U. Kuhlmann, H. Dau, P. Hildebrandt, J. Roithová, K. Ray, Angew. Chem. Int. Ed. 2021, DOI: 10.1002/anie.202108442.
- "Stable, but still reactive - investigations on the effects of Lewis acid binding on copper nitrene intermediates"
K. Warm, I. Monte-Pérez, U. Kuhlmann, P. Hildebrandt, E. Farquhar, M. Swart, K. Ray, Zeitschrift für anorganische und allgemeine Chemie 2021, DOI: 10.1002/zaac.202100092.
- "Ligand Constraint Induced Peroxide Activation for Electrophilic Reactivity"
A. Chandra, M. Ansari, I. Monte-Pérez, S. Kundu, G. Rajaraman, and K. Ray, Angew. Chem. Int. Ed. 2021, DOI: 10.1002/anie.202100438.
- "Transition metal-mediated O-O bond formation and activation in chemistry and biology"
X.-P. Zhang, A. Chandra, Y.-M. Lee, R. Cao, K. Ray, and W. Nam, Chem. Soc. Rev. 2021, DOI: 10.1039/D0CS01456G.
- "A Bioinspired Oxoiron(IV) Motif Supported on a N2S2 Macrocyclic Ligand"
J. Deutscher, P. Gerschel, K. Warm, U. Kuhlmann, S. Mebs, M. Haumann, H. Dau, P. Hildebrandt, U.-P. Apfel, K. Ray, Chem. Comm. 2021, DOI: 10.1039/D1CC00250C.
- "A Pseudotetrahedral Terminal Oxoiron(IV) Complex: Mechanistic Promiscuity in C-H bond Oxidation Reactions"
K. Warm, A. Paskin, U. Kuhlmann, E. Bill, M. Swart, M. Haumann, H. Dau, P. Hildebrandt, K. Ray, Angew. Chem. Int. Ed. 2021, 60, 6752-6756. DOI: 10.1002/anie.202015896.
- "Synthesis, Characterization, and Reactivity of a Series of Homo- and Hetero-dinuclear Complexes based on an Asymmetric FloH Ligand System"
B. Battistella, F. Heims, B. Cula, K. Ray, Zeitschrift für anorganische und allgemeine Chemie 2020, DOI: 10.1002/zaac.202000221.
- "Redox Potentials of High-Valent Iron-, Cobalt-, and Nickel-Oxido Complexes: Evidence for Exchange Enhanced Reactivity"
P. Comba, A.-M. Löhr, F. Pfaff, K. Ray, Israel Journal of Chemistry 2020, DOI: 10.1002/ijch.202000038.
- "Iron and manganese oxo complexes, the oxo wall and beyond"
V. A. Larson, B. Battistella, K. Ray, N. Lehnert, W. Nam, Nature Reviews Chemistry 2020, DOI: 10.1038/s41570-020-0197-9.
- "Electrochemical CO2 Reduction - The Effect of Chalcogenide Exchange in Ni-Isocyclam Complexes"
P. Gerschel, B. Battistella, D. Siegmund, K. Ray, U. P. Apfel, Organometallics 2020, DOI: 10.1021/acs.organomet.0c00129.
- "Catalytic dioxygen reduction mediated by a tetranuclear cobalt complex supported on a stannoxane core"
A. Chandra, S. Mebs, S. Kundu, U. Kuhlmann, P. Hildebrandt, H. Dau, K. Ray, Dalton Trans. 2020, DOI: 10.1039/d0dt00475h.
- "O2 and H2O2 activations at dinuclear Mn and Fe active sites"
B. Battistella, K. Ray, Coordination Chemistry Reviews 2020, DOI: 10.1016/j.ccr.2019.213176.
- "Stoichiometric Formation of an Oxoiron(IV) Complex by a Soluble Methane Monooxygenase Type Activation of O2 at an Iron(II)-Cyclam Center"
D. Kass, T. Corona, K. Warm, B. Braun-Cula, U. Kuhlmann, E. Bill, S. Mebs, M. Swart, H. Dau, M. Haumann, P. Hildebrandt, K. Ray, J. Am. Chem. Soc. 2020, DOI: 10.1021/jacs.9b13756.
- "Trapping of a Highly Reactive Oxoiron(IV) Complex in the Catalytic Epoxidation of Olefins by Hydrogen Peroxide"
X. Engelmann, D. D. Malik, T. Corona, K. Warm, E. R. Farquhar, M. Swart, W. Nam, K. Ray, Angew. Chem. Int. Ed. 2019, DOI: 10.1002/anie.201812758.
- "Sulfur substitution in a Ni(cyclam) derivative results in lower overpotential for CO2 reduction and enhanced proton reduction"
P. Gerschel, K. Warm, E. R. Farquhar, U. Englert, M. L. Reback, D. Siegmund, K. Ray, U.-P. Apfel, Dalton Trans. 2019, DOI: 10.1039/c8dt04740e.
- "Heme and Nonheme High-Valent Iron and Manganese Oxo Cores in Biological and Abiological Oxidation Reactions"
M. Guo, T. Corona, K. Ray, W. Nam, ACS Cent. Scie. 2019, DOI: 10.1021/acscentsci.8b00698.
- "Water Oxidation Reaction Mediated by an Octanuclear Iron-Oxo Cluster"
J. Deutscher, T. Corona, K. Warm, X. Engelmann, S. Sobottka, B. Braun-Cula, B. Sarkar, K. Ray, Eur. J. Inorg. Chem. 2018, 45, 4925–4929.
- "Structure, bonding, reactivity and spectral features of putative NiIII=O species: a theoretical perspective"
B. Pandey, K. Ray, G. Rajaraman, Z. anorg. allg. Chem. 2018, 644, 790-800.
- "Observation of Carbodicarbene Ligand Redox Noninnocence in Highly Oxidized Iron Complexes"
S. C. Chan, P. Gupta, X. Engelmann, Z. Z. Ang, R. Ganguly, E. Bill, K. Ray, S. Ye, J. England, Angew. Chemie Int. Ed. 2018, 57, 1-7.
- "Four-electron reduction of dioxygen to water by a trinuclear copper complex"
X. Engelmann, E. R. Farquhar, J. England, K. Ray, Inorg. Chem. Acta 2018, 481, 159-165.
- "Nucleophilic vs. Electrophilic Reactivity of Bioinspired Super‐oxido Nickel(II) Complexes"
C. Panda, A. Chandra, T. Corona, E. Andris, B. Pandey, S. Garai, N. Lindenmaier, S. Kuenstner, E. R. Farquhar, J. Roithova, G. Rajaraman, M. Driess, K. Ray, Angew. Chem. Int. Ed. 2018, 57, 14883-14887.
- "C-H activation and nucleophilic substitution in a photochemically generated high valent iron complex"
J. Hui Lim, X. Engelmann, S. Corby, R. Ganguly, K. Ray, H. S. Soo, Chem. Sci. 2018, 9, 3992-4002.
- "A Highly Reactive Oxoiron(IV) Complex Supported by a Bioinspired N3O Macrocyclic Ligand"
I. Monte Pérez, X. Engelmann, Y.-M. Lee, M. Yoo, K. Elumalai, E. R. Farquhar, E. Bill, J. England, W. Nam, M. Swart, K. Ray, Angew. Chem. Int. Ed. 2017, 56, 14384-14388.
- "Temperature Dependence of the Catalytic Two- versus Four Electron Reduction of Dioxygen by a Hexanuclear Cobalt Complex"
I. Monte-Pérez, S. Kundu, A. Chandra, K. E. Craigo, P. Chernev, U. Kuhlmann, H. Dau, P. Hildebrandt, C. Greco, C. Van Stappen, N. Lehnert, K. Ray, J. Am. Chem. Soc.2017, 139, 15033-15042.
- "A High-Valent Non-Heme μ-Oxo Manganese(IV) Dimer Generated from a Thiolate-Bound Manganese(II) Complex and Dioxygen"
D. Brazzolotto, F. G. Cantú Reinhard, J. Smith-Jones, M. Retegan, L. Amidani, A. S. Faponle, K. Ray, C. Philouze, S. P. de Visser, M. Gennari, C. Duboc, Angew. Chem. Int. Ed. 2017, 56, 8211-8215.
- "Synthesis and reactivity of a mononuclear non-haem cobalt(IV)-oxo complex"
B. Wang, Y.-M. Lee, W.-Y. Tcho, S. Tussupbayev, S.-T. Kim, Y. Kim, M. S. Seo, K.-B. Cho, Y. Dede, B. C. Keegan, T. Ogura, S. H. Kim, T. Ohta, M.-H. Baik, K. Ray, J. Shearer, W. Nam Nat. Commun. 2017, 8, 14839.
- "A New Domain of Reactivity for High-Valent Dinuclear [M(µ-O2M'] Complexes in Oxidation Reactions"
X. Engelmann, S. Yao, E. R. Farquhar, T. Szilvási, U. Kuhlmann, P. Hildebrandt, M. Driess, K. Ray, Angew. Chem. 2017, 56, 303-307.
- "Characterization and reactivity studies of a terminal copper-nitrene species."
T. Corona, L. Ribas, M. Rovira, E. R. Farquhar, X. Ribas, K. Ray, A. Company, Angew. Chem. Int. Ed. 2016, 55, 14005-14008.
- "A cobalt(II) iminoiodane complex and its scandium adduct: mechanistic promiscuity in hydrogen atom abstraction reactions"
S. Kundu, P. Chernev, X. Engelmann, C. S. Chung, H. Dau, E. Bill, J. England, W. Nam, K. Ray, Dalton Trans. 2016, 45, 14538-14543.
- "Changing the chemical and physical properties of high valent heterobimetallic bis-(μ-oxido) Cu-Ni complexes by ligand effects"
M.-C. Kafentzi, M. Orio, M. Reglier, S. Yao, U. Kuhlmann, P. Hildebrandt, M. Driess, A. J. Simaan, K. Ray, Dalton Trans. 2016, 45, 15994-16000.
- "Dioxygen activation chemistry by synthetic mononuclear nonheme iron, copper and chromium complexes"
S. Hong, Y.-M. Lee, K. Ray, W. Nam, Coord. Chem. Rev. 2016, 334, 25-42.
- "An iron(II) hydride complex of a ligand with two adjacent β-diketiminate binding sites and its reactivity"
H. Gehring, R. Metzinger, B. Braun, C. Herwig, S. Harder, K. Ray, C. Limberg, Dalton Trans. 2016, 45, 2989-2996.
- "Oxidation Reactions with Bioinspired Mononuclear Non-Heme Metal-Oxo Complexes:"
X. Engelmann, I. M.-Pérez, K. Ray, Angew. Chem. Int. Ed. 2016, 55, 7632-7649.
Inside Cover Picture
- "High-Valent Metal-Oxo Intermediates in Energy Demanding Processes: From Dioxygen Reduction to Water Splitting:"
F. Heims, K. Ray, M. Schwalbe and W. Nam, Curr. Opin. Chem. Biol. 2015, 25, 159-171.
- "An Open-Shell Spin Singlet Copper-Nitrene Intermediate Binding Redox-innocent Metal Ions: Influence of the Lewis Acidity of the Metal Ions on Spectroscopic and Reactivity Properties:"
I. M.-Pérez, S. Kundu, and K. Ray, Z. anorg. allg. Chem. 2015, 641, 78–82.
- "Characterization of Porphyrin-Co(III)-‘Nitrene radical’ species relevant in catalytic nitrene transfer reactions:"
M. Goswami, V. Lyaskovskyy, S. R. Domingos, W. J. Buma, S. Woutersen, O. Troeppner, I. I-Burmazović, H. Lu, X. Cui, P. Zhang, E. J. Reijerse, S. DeBeer, M. M. van Schooneveld, F. Pfaff, K. Ray and B. de Bruin, J. Am. Chem. Soc. 2015, 137, 5468–5479.
- "Reactivity of a Nickel(II) Bis-amidate Complex with HmCPBA: Formation of a Potent Oxidizing Species:"
T. Corona, F. F. Pfaff, F. Acuña-Parés, A. Draksharapu, C. J. Whiteoak, V. Martin-Diaconescu, J. L-Fillol, W. R. Browne, K. Ray, A. Company, Chem. Eur. J. 2015, 21, 15029-15038.
- Simple Access to the Homoleptic Ni(I)-Olefin-Complex Ni(cod)2+[Al(ORF)4]– and its Use as a Starting Material for Further Ni(I)-Chemistry:"
M. Schwab, D. Himmel, S. Kacprzak, D. Kratzert, V. Radtke, M. Wernet, P. Weis, K. Ray, E. W. Scheidt, W. Scherer, B. de Bruin, T. Augenstein, F. Breher, S. Weber, I. Krossing, Angew. Chem. Int. Ed. 2015, 54, 14706-14709.
- "Spectroscopic Capture and Reactivity of a Low-Spin Cobalt(IV)-Oxo Complex Stabilized by Binding Redox-Inactive Metal Ions"
S. Hong, F. F. Pfaff, E. Kwon, Y. Wang, M.-S. Seo, E. Bill, K. Ray, and W. Nam, Angew. Chem. Int. Ed. 2014, 53, 10403-1407.
- "Evidence of Two-State Reactivity in Alkane Hydroxylation by Lewis-acid Bound Copper-Nitrene Complexes"
S.-L. Abram, I. Monte-Pérez, F. F. Pfaff, E. Farquhar, and K. Ray, Chem. Commun. 2014, 50, 9852-9854.
- "Status of Reactive Non-Heme Metal-Oxygen Intermediates in Chemical and Enzymatic Reactions"
K. Ray, F. F. Pfaff, B. Wang, and W. Nam, J. Am. Chem. Soc. 2014, 136, 13942-13958.
- "Redox Non-Innocence of a N-Heterocyclic Nitrenium Cation Bound to a Nickel–Cyclam Core"
F. Heims, F. F. Pfaff, S.-L. Abram, E. R. Farquhar, M. Bruschi, C. Greco, and K. Ray, J. Am. Chem. Soc. 2014, 136, 582-585.
- "Mechanism of phenol oxidation by heterodinuclear Ni Cu bis(µ-oxo) complexes involving nucleophilic oxo groups"
S. Kundu, E. Miceli, E. R. Farquharb and K. Ray, Dalton Trans. 2014, 43, 4264-4267.
- "Access to a CuII–O–CuII Motif: Spectroscopic Properties, Solution Structure, and Reactivity"
P. Haack, A. Kärgel, C. Greco, J. Dokic, B. Braun, F. F. Pfaff, S. Mebs, K. Ray, and C. Limberg, J. Am. Chem. Soc. 2013, 135, 16148-16160.
- "A High-Valent Heterobimetallic [CuIII(μ-O)2NiIII]2+ Core with Nucleophilic Oxo Groups"
- "Terminal oxo and imido transition metal complexes of Groups 9-11"
K. Ray, F. Heims, F. F. Pfaff, Eur. J. Inorg. Chem. 2013, 3784-3807.Invited Review
- "Nonheme oxoiron(IV) complexes of pentadentate N5 ligands: spectroscopy, electrochemistry, and oxidative reactivity"
D. Wang, K. Ray, M. J. Collins, E. R. Farquhar, J. R. Frisch, L. Gomez, T. A. Jackson, M. Kerscher, A. Waleska, P. Comba, M. Costas, L. Que Jr., Chemical Science 2013, 4, 282-291.
- "Lewis-acid Trapping of an Elusive Copper-Tosylnitrene Intermediate Using Scandium Triflate"
S. Kundu, E. Miceli, E. Farquhar, F. F. Pfaff, U. Kuhlmann, P. Hildebrandt, B. Braun, C. Greco, K. Ray, J. Am. Chem. Soc. 2012, 134, 14710-14713.
- "Metal-oxo-mediated O-O bond formation reactions in chemistry and biology"
S. Kundu, M. Schwalbe, K. Ray, BioInorg. React. Mech. 2012, 8, 41-57.
- "Synthesis and Spectroscopic Characterisation of a Heterodinuclear Iron(III)-Copper(II) Complex Based on an Asymmetric Dinucleating Ligand System"
F. Heims, V. Mereacre, A. Ciancetta, S. Mebs, A. K. Powell, C. Greco and K. Ray, Eur. J. Inorg. Chem. 2012, 29, 4565-4569.
- "The biology and chemistry of high-valent iron–oxo and iron–nitrido complexes"
J. Hohenberger, K. Ray, K. Meyer, Nature Commun. 2012, 3, 720.
- "Spectroscopic capture and reactivity of S = 1/2 nickel(III)–oxygen intermediates in the reaction of a NiII-salt with mCPBA"
F. F. Pfaff , F. Heims , S. Kundu , S. Mebs and K. Ray, Chem. Commun. 2012, 48, 3730-3732.
- "O-O Bond Formation Mediated by a Hexanuclear Iron Complex Supported on a Stannoxane Core"
S. Kundu, E. Matito, S. Walleck, F. F. Pfaff, F. Heims, B. Rábay, J. M. Luis, A. Company, B. Braun, T. Glaser, and K. Ray, Chem. Eur. J. 2012, 10, 2787-2791.
- "An Oxocobalt(IV) Complex Stabilized by Lewis Acid Interactions with Scandium(III) Ions."
F. F. Pfaff, S. Kundu, M. Risch, S. Pandian, F. Heims, I. Pryjomska-Ray, P. Haack, R. Metzinger, E. Bill, H. Dau, P. Comba, K. Ray, Angew. Chem. Int. Ed. 2011, 7, 1711-1715.
- "Dinuclear Copper Complexes Based on Parallel ß-Diiminato Binding Sites and their Reactions with O2: Evidence for a Cu-O-Cu Entity"
P. Haack, C. Limberg, K. Ray, B. Braun, U. Kuhlmann, P. Hildebrandt, and C. Herwig, Inorg. Chem. 2011, 6, 2133-2142.
- "Dioxygenase-Like Reactivity of an Isolable Superoxo-Nickel(II) Complex."
A. Company, S. Yao, K. Ray, M. Driess, Chem. Eur. J. 2010, 16, 9669-9675.
- "Determination by High-Frequency and -Field EPR of Zero-Field Splitting in Iron(IV) Oxo Complexes: Implications for Intermediates in Nonheme Iron Enzymes"
J. Krzystek, J. England, K. Ray, A. Ozarowski, D. Smirnov, L. Que Jr., J. Telser, Inorg. Chem. 2008, 47, 3483-3485.
- "An Inverted and More Oxidizing Isomer of [FeIV(O)(TMC)(NCCH3)]2+."
K. Ray, J. England, M. Martinho, E. Munck, L. Que Jr., Angew. Chem. 2008, 120, 8188-8191.
- "Iron-Oxidation-State Dependent O-O bond cleavage in meta-chloroperbenzoic acid to form an oxoiron(IV) complex."
K. Ray, S. M. Lee, L. Que Jr., Inorg. Chim. Acta 2008, 361, 1066-1069.
- "Description of the Ground-State Covalencies of the Bis(dithiolato) Transition-Metal Complexes from X-ray Absorption Spectroscopy and Time-Dependent Density-Functional Calculations."
K. Ray, S. D. George, E. I. Solomon, K. Wieghardt, and F. Neese, Chem. Eur. J. 2007, 13, 2783-2797.
- "Molecular and Electronic Structure of Square-Planar Gold Complexes Containing Two 1,2-Di(4-tert-butylphenyl)ethylene-1,2-dithiolato Ligands: [Au(2L)2]1+/0/1-/2-. A Combined Experimental and Computational Study"
S. Kokatam, K. Ray, J. Pap, E. Bill, W. E. Geiger, R. J. LeSuer, P. H. Rieger, T. Weyhermüller, F. Neese, K. Wieghardt, Inorg. Chem. 2007, 46, 1100-1111.
- "Axial Ligand Tuning of a Nonheme Iron(IV)-Oxo Unit for Hydrogen Atom Abstraction."
C. V. Sastri, J. Lee, K. Oh, Y. J. Lee, J. Lee, T. A. Jackson, K. Ray, H. Hirao, W. Shin, J. A. Halfen, L. Que Jr., S. Shaik, and W. Nam, Proc. Natl. Acad. Sc. 2007, 104, 19181-19186.
- "Joint Spectroscopic and Theoretical Investigations of Transition Metal Complexes Involving Non-innocent ligands."
K. Ray, T. Petrenko, K. Wieghardt, F. Neese, Dalton Trans. 2007, 16, 1552-1566.
- "Electrochemical Generation of a Nonheme Oxoiron(IV) Complex."
M. J. Collins, K. Ray, L. Que Jr., Inorg. Chem. 2006, 45, 8009-8011.
- "Vibrational Markers for the Open-Shell Character of Transition Metal Bis-dithiolenes: An Infrared, Resonance Raman, and Quantum Chemical Study."
T. Petrenko, K. Ray, K. Wieghardt, F. Neese, J. Am. Chem. Soc. 2006, 128, 4422-4436.
- "Molecular and Electronic Structures of Oxo-bis(benzene-1,2-dithiolato)chromate(V) Monoanions. A Combined Experimental and Density Functional Study."
R. Kapre, K. Ray; I. Sylvestre, T. Weyhermüller, S. D. George, F. Neese, K. Wieghardt, Inorg. Chem. 2006, 45, 3499-3509.
- "A Lipophilic Hexaporphyrin Assembly Supported on a Stannoxane Core."
V. Chandrasekhar, S. Nagendran, R. Azhakar, M. R. Kumar, A. Srinivasan, K. Ray, T. K. Chandrashekar, C. Madhavaiah, S. Verma, U. D. Priyakumar, G. N. Sastry, J. Am. Chem. Soc. 2005, 127, 2410-2411.
- "Electronic Structure of Square Planar Bis(benzene-1,2-dithiolato)metal Complexes [M(L)2]z (z = 2-, 1-, 0; M = Ni, Pd, Pt, Cu, Au): An Experimental, Density Functional, and Correlated ab initio Study."
K. Ray, T. Weyhermüller, F. Neese, and K. Wieghardt, Inorg. Chem. 2005, 44, 5345-5360.
- "Redox-Noninnocence of the S,S'-Coordinated Ligands in Bis(benzene-1,2-dithiolato)iron Complexes."
K. Ray, E. Bill, T. Weyhermüller, K. Wieghardt, J. Am. Chem. Soc. 2005, 127, 5641-5654.
- "The Electronic Structure of the Isoelectronic, Square Planar Complexes, [FeII(L)2]2- and [CoIII(LBu)2]- (L2- and (LBu)2- = benzene-1,2-dithiolates): An Experimental and Density Functional Theoretical Study."
K. Ray, A. Begum, T. Weyhermüller, S. Piligkos, J. van Slageren, F. Neese, K. Wieghardt, J. Am. Chem. Soc. 2005, 127, 4403-4415.
- "Molecular and Electronic Structure of Four- and Five- Coordinate Cobalt Complexes Containing Two o-Phenylenediamine- or two o-Aminophenol-Type Ligands at Various Oxidation Levels: An Experimental, Density Functional, and Correlated ab initio Study."
E. Bill, E. Bothe, P. Chaudhuri, K. Chlopek, D. Herebian, S. Kokatam, K. Ray, T. Weyhermüller, F. Neese, K. Wieghardt, Chem. Eur. J. 2004, 11, 204-224.
- "Do S,S'–Coordinated o-dithiobenzosemiquinonate(1-) Radicals Exist in Coordination Compounds? The [AuIII(1,2-C6H4S2)2]1-/0 Couple."
K. Ray, T. Weyhermüller, A. Goossens, M. W. J. Crajé, and K. Wieghardt, Inorg. Chem. 2003, 42, 4082-4087.