Dr. Marco Flores was born in Perú where he earned a B.Sc. degree in Physics at the National University of Engineering (Lima, Perú). After obtaining his Bachelor’s degree Marco Flores won a CAPES scholarship (Ministry of Education, Brazil) to support his graduate research in the Biophysics Group at the Brazilian Center for Research on Physics (Rio de Janeiro, Brazil). In Brazil, he studied the ligand structure in heme proteins and received his Ph.D. degree in Biophysics in 2000.
For his postdoctoral work Dr. Flores challenged himself by joining the renowned research group of Professor George Feher in La Jolla (University of California, San Diego) where he worked on the elucidation of the primary processes in bacterial photosynthesis. After his training in USA, Dr. Flores decided to join the Max-Planck Institute for Bioinorganic Chemistry (Mülheim an der Ruhr, Germany) as a European Union Research Fellow and investigated the structure and function of the enzyme [NiFe] hydrogenase. This enzyme is important for a future biologically-based hydrogen production technology.
Since September 2008, Dr. Flores is at Arizona State University as an Academic Professional and Manager of the Electron Paramagnetic Resonance (EPR) Facility. He has extensive experience on the use of modern EPR techniques. It covers both the application of routine and non-routine methods (e.g. ENDOR, ELDOR and ESEEM), and the analysis of data.
B.Sc. Physics, National University of Engineering, Perú, 1993. M.Sc. Physics, Brazilian Center for Research on Physics, Brazil, 1996. Ph.D. Physics, Brazilian Center for Research on Physics, Brazil, 2000. Post-Doc Biophysics, University of California, San Diego, 2000-2004
Dr. Flores' research work focuses on the study of radicals, radical pairs, triplet states and transition metal complexes involved in bioenergetics and related model systems using modern EPR spectroscopy. In particular, Dr. Flores is investigating the electronic structure of metals at a metal-binding site introduced in modified bacterial reaction centers or in artificial metalloproteins. The metal-binding site is designed to mimic the one present in photosystem II, which harbors the oxygen evolving Mn cluster. Furthermore, he collaborates with other investigators whose research spans across various disciplines, including biophysics, biochemistry, physical chemistry, material science and inorganic chemistry.
Comparing the electronic structure of iron, cobalt, and nickel compounds that feature a phosphine-substituted bis(imino)pyridine chelate. M. R. Mena, J. H. Kim, S. So, H. Ben-Daat, T. M. Porter, C. Ghosh, A. Sharma, M. Flores, T. L. Groy, M. H. Baik and R. J. Trovitch. Inorg. Chem. 61, 6438-6450 (2022).
The electronic structure of a β-diketiminate manganese hydride dimer. C. Oh, J. Siewe, T. T. Nguyen, A. Kawamura, M. Flores, T. L. Groy, J. S. Anderson, R. J. Trovitch and M. H. Baik. Dalton Trans. 49, 14463-14474 (2020).
Scope and mechanism of nitrile dihydroboration mediated by a β-diketiminate manganese hydride catalyst. T. T. Nguyen, J. H. Kim, S. Kim, C. Oh, M. Flores, T. L. Groy, M. H. Baik and R. J. Trovitch. Chem. Commun. 56, 3959-3962 (2020).
Redox-noninnocent ligand-supported vanadium catalysts for the chemoselective reduction of C=X (X = O, N) functionalities. G. Zhang, J. Wu, S. Zheng, M. C. Neary, J. Mao, M. Flores, R. J. Trovitch and P. A. Dub. J. Am. Chem. Soc. 141, 15230-15239 (2019).
A β-diketiminate manganese catalyst for alkene hydrosilylation: Substrate scope, silicone preparation, and mechanistic insight. T. K. Mukhopadhyay, M. Flores, T. L. Groy and R. J. Trovitch. Chem. Sci. 9, 7673-7680 (2018).
Electrocatalytic properties of binuclear Cu(II) fused porphyrins for hydrogen evolution. D. Khusnutdinova, B. L. Wadsworth, M. Flores, A. M. Beiler, E. A. R. Cruz, Y. Zenkov and G. F. Moore. ACS Catal. 8, 9888-9898 (2018).
Isolation of Mn(I) compounds featuring a reduced bis(imino)pyridine chelate and their relevance to electrocatalytic hydrogen production. T. K. Mukhopadhyay, N. L. MacLean, M. Flores, T. L. Groy and R. J. Trovitch. Inorg. Chem. 57, 6065-6075 (2018).
Synthesis and characterization of a cobalt(II) tetrakis(3-fluorophenyl)porphyrin with a built-in 4-vinylphenyl surface attachment moiety. D. Khusnutdinova, M. Flores, A. M. Beiler and G. F. Moore. Photosynthetica, 56, 67-74 (2018).
Hydrosilylation of aldehydes and formates using a dimeric manganese precatalyst. T. K. Mukhopadhyay, C. Ghosh, M. Flores, T. L. Groy and R. J. Trovitch. Organometallics, 36, 3477-3483 (2017).
Biochemical and spectroscopic characterization of dinuclear Mn-sites in artificial four-helix bundle proteins. T. L. Olson, E. Espiritu, S. Edwardraja, E. Canarie, M. Flores, J. C. Williams, G. Ghirlanda and J. P. Allen. Biochim. Biophys. Acta - Bioenerg. 1858, 945-954 (2017).
Hydroboration of alkynes and nitriles using an α-diimine cobalt hydride catalyst. H. Ben-Daat, C. L. Rock, M. Flores, T. L. Groy, A. C. Bowman and R. J. Trovitch. Chem. Commun. 53, 7333-7336 (2017).
Isolation of a bis(imino)pyridine molybdenum(I) iodide complex through controlled reduction and interconversion of its reaction products. R. Pal, B. R. Cherry, M. Flores, T. L. Groy and R. J. Trovitch. Dalton Trans. 45, 10024-10033 (2016).
Thermodynamics of the electron acceptors in Heliobacterium modesticaldum: An exemplar of an early homodimeric type I photosynthetic reaction center. B. Ferlez, J. Cowgill, W. Dong, C. Gisriel, S. Lin, M. Flores, K. Walters, D. Cetnar, K. E. Redding and J. H. Golbeck. Biochemistry 55, 2358-2370 (2016).
A pentacoordinate Mn(II) precatalyst that exhibits notable aldehyde and ketone hydrosilylation turnover frequencies. C. Ghosh, T. K. Mukhopadhyay, M. Flores, T. L. Groy and R. J. Trovitch. Inorg. Chem. 54, 10398-10406 (2015).
Copper environment in artificial metalloproteins probed by electron paramagnetic resonance spectroscopy. M. Flores, T. L. Olson, D. Wang, S. Edwardraja, S. Shinde, J. C. Williams, G. Ghirlanda and J. P. Allen. J. Phys. Chem. B 119, 13825-13833 (2015).
A new spin on cyclooctatetraene (COT) redox-activity: Low-spin iron(I) complexes that exhibit antiferromagnetic coupling to a singly reduced η4-COT ligand. T. K. Mukhopadhyay, M. Flores, R. K. Feller, B. L. Scott, R. D. Taylor, M. Paz-Pasternak, N. J. Henson, F. N. Rein, N. C. Smythe, R. J. Trovitch and J. C. Gordon. Organometallics 33, 7101-7112 (2014).
Expression and characterization of cytochrome c553 from Heliobacterium modesticaldum. T. S. Kashey, J. B. Cowgill, M. D. McConnell, M. Flores and K. E. Redding. Photosynth. Res. 120, 291-299 (2014).
Electronic structure of the Mn-cofactor of modified bacterial reaction centers measured by electron paramagnetic resonance and electron spin echo envelope modulation spectroscopies. A. A. Tufts, M. Flores, T. L. Olson, J. C. Williams and J. P. Allen. Photosynth. Res. 120, 207-220 (2014).
Interface for light-driven electron transfer by photosynthetic complexes across block copolymer membranes. L. Kuang, T. L. Olson, S. Lin, M. Flores, Y. Jiang, W. Zheng, J. C. Williams, J. P. Allen and H. Liang. J. Phys. Chem. Lett. 5, 787-791 (2014).
A highly active manganese precatalyst for the hydrosilylation of ketones and esters. T. K. Mukhopadhyay, M. Flores, T. L. Groy and R. J. Trovitch. J. Am. Chem. Soc. 136, 882-885 (2014).
Study and manipulation of charges present in silicon nitride films. V. Sharma, C. Tracy, D. Schroder, M. Flores, B. Dauksher and S. Bowden. in Photovoltaic Specialists Conference (PVSC), 2013 IEEE 39th, pags. 1288-1293, IEEE (2013).
Sequential oxidations of thiolates and the cobalt metallocenter in a synthetic metallopeptide: Implications for the biosynthesis of nitrile hydratase. A. Dutta, M. Flores, S. Roy, J. C. Schmitt, G. A. Hamilton, H. E. Hartnett, J. M. Shearer and A. K. Jones. Inorg. Chem. 52, 5236-5245 (2013).
Microwave loss in the high-performance dielectric Ba(Zn1/3Ta2/3)O3 at 4.2 K. L. Liu, M. Flores and N. Newman. Phys. Rev. Lett. 109, 257601 (2012).
Pulse Q-band EPR and ENDOR spectroscopies of the photochemically generated monoprotonated benzosemiquinone radical in frozen alcoholic solution. M. Flores, M. Y. Okamura, J. Niklas, M. E. Pandelia and W. Lubitz. J. Phys. Chem. B 116, 8890-8900 (2012).
High-quality manganese-doped zinc sulfide quantum rods with tunable dual-color and multiphoton emissions. Z. Deng, L. Tong, M. Flores, S. Lin, J. X. Cheng, H. Yan and Y. Liu. J. Am. Chem. Soc. 133, 5389-5396 (2011).
Electron-nuclear and electron-electron double resonance spectroscopies show that the primary quinone acceptor QA in reaction centers from photosynthetic bacteria Rhodobacter sphaeroides remains in the same orientation upon light-induced reduction. M. Flores, A. Savitsky, M. L. Paddock, E. C. Abresch, A. A. Dubinskii, M. Y. Okamura, W. Lubitz and K. Möbius. J. Phys. Chem. B 114, 16894-16901 (2010).
Inhibition of the [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F by carbon monoxide: An FTIR and EPR spectroscopic study. M. E. Pandelia, H. Ogata, L. J. Currell, M. Flores and W. Lubitz. Biochim. Biophys. Acta - Bioenerg. 1797, 304-313 (2010).
EPR and ENDOR investigation of rhodosemiquinone in bacterial reaction centers formed by B-branch electron transfer. M. L. Paddock, M. Flores, R. Isaacson, J. N. Shepherd and M. Y. Okamura. Appl. Magn. Reson. 37, 39-48 (2010).
Electronic structure of Fe3+ at a metal-binding site introduced in modified bacterial reaction centers. L. Kálmán, M. Flores, J. C. Williams and J. P. Allen. Appl. Magn. Reson. 37, 27-37 (2010).
Probing intermediates in the activation cycle of [NiFe] hydrogenase by infrared spectroscopy: the Ni-SIr state and its light sensitivity. M. E. Pandelia, H. Ogata, L. J. Currell, M. Flores and W. Lubitz. J. Biol. Inorg. Chem. 14, 1227-1241 (2009).
Electronic structure of a binuclear nickel complex of relevance to [NiFe] hydrogenase. M. van Gastel, J. L. Shaw, A. J. Blake, M. Flores, M. Schröder, J. McMaster and W. Lubitz. Inorg. Chem. 47, 11688-11697 (2008).
Electron-electron double resonance-detected NMR to measure metal hyperfine interactions: 61Ni in the Ni-B state of the [NiFe] hydrogenase of Desulfovibrio vulgaris Miyazaki F. M. Flores, A. G. Agrawal, M. van Gastel, W. Gärtner and W. Lubitz. J. Am. Chem. Soc. 130, 2402-2403 (2008).
Structure of radical pairs D.+QA.- in bacterial photosynthetic reaction centers cooled to cryogenic temperatures in the dark and under illumination: A high-field EPR/PELDOR study. M. Flores, A. Savitsky, E. C. Abresch, W. Lubitz and K. Möbius. in Photosynthesis. Energy from the Sun: 14th International Congress on Photosynthesis, eds. J. F. Allen, E. Gantt, J. H. Golbeck and B. Osmond, pags. 59-63, Springer, Berlin (2008).
ENDOR spectroscopy reveals light induced movement of the H-bond from Ser-L223 upon forming the semiquinone (QB.-) in reaction centers from Rhodobacter sphaeroides. M. L. Paddock, M. Flores, R. Isaacson, C. Chang, E. C. Abresch and M. Y. Okamura. Biochemistry 46, 8234-8243 (2007).
Orientation-resolving pulsed electron dipolar high-field EPR spectroscopy on disordered solids: I. Structure of spin-correlated radical pairs in bacterial photosynthetic reaction centers. A. Savitsky, A. A. Dubinskii, M. Flores, W. Lubitz and K. Möbius. J. Phys. Chem. B 111, 6245-6262 (2007).
Protein-cofactor interactions in bacterial reaction centers from Rhodobacter sphaeroides R-26: II. Geometry of the hydrogen bonds to the primary quinone QA.- by 1H and 2H ENDOR spectroscopy. M. Flores, R. Isaacson, E. Abresch, R. Calvo, W. Lubitz and G. Feher. Biophys. J. 92, 671-682 (2007).
Trapped conformational states of semiquinone (D.+QB.-) formed by B-branch electron transfer at low temperature in Rhodobacter sphaeroides reaction centers. M. L. Paddock, M. Flores, R. Isaacson, C. Chang, E. C. Abresch, P. Selvaduray and M. Y. Okamura. Biochemistry 45, 14032-14042 (2006).
Protein-cofactor interactions in bacterial reaction centers from Rhodobacter sphaeroides R-26: Effect of hydrogen bonding on the electronic and geometric structure of the primary quinone. A density functional theory study. S. Sinnecker, M. Flores and W. Lubitz. Phys. Chem. Chem. Phys. 8, 5659-5670 (2006).
Protein-cofactor interactions in bacterial reaction centers from Rhodobacter sphaeroides R-26: I. Identification of the ENDOR lines associated with the hydrogen bonds to the primary quinone QA.-. M. Flores, R. Isaacson, E. Abresch, R. Calvo, W. Lubitz and G. Feher. Biophys. J. 90, 3356-3362 (2006).
- European Union/Energy Network Project (SOLAR-H), Research Fellow (2004-2008)
- National Institutes of Health (NIH), Postdoctoral Research Fellow (2000-2004)
- Sociedade Brasileira de Física
- International EPR Society
- American Chemical Society
- Applied Magnetic Resonance, Reviewer (2021)
- National Science Foundation, MRI Program, EPR Review Panel, Member (2017)
- National Science Foundation, MRI Program, Ad hoc Reviewer (2016)
- National Science Foundation, MRI Program, EPR Review Panel, Member (2015)
- The Journal of Physical Chemistry B, Reviewer (2015)
- Biochimica et Biophysica Acta - Bioenergetics, Reviewer (2010)