Research Areas Catalytic processes of hydrogenation, deuteration and deuterogenation of organic substrates using ruthenium complexes, including hydride and polyhydride derivatives (UCLM). Metal-Organic Supramolecular Chemistry. Study of non-covalent interactions. MOF structures and their use for gas storage. Cytotoxicity of transition metal complexes. Catalytic photogeneration of hydrogen from water using transition metal complexes. Catalytic processes of hydrogenation, deuteration and deuterogenation of organic substrates using ruthenium complexes, including hydride and polyhydride derivatives (UCLM). Our group has been particularly interested in the study of polyhydride derivatives of transition metals and we have published more than 15 papers on this topic (see CV of F. Jalón). Of particular relevance are the results concerning the first non-rotating H2 coordinated molecule,1 the first examples of Tp-polyhydrides of Ru,2 one exceptional case of enantiotopic proton transfer3 and one of the rare examples of H+/D+ exchange in the H2 molecule using CD3OD as the D-source.4 Leveraging our knowledge in this field, a current area of interest for our group is the design of processes to achieve selective and efficient deuterium labelling of organic molecules, preferably using D2O as the deuterium source.5 Processes such as C–H activation and deuterogenation of unsaturated substrates are fundamental in achieving this goal. In the transfer hydrogenation with i-PrOH, we have developed catalytic processes for the hydrogenation of ketones and aldehydes with ruthenium complexes containing bis(pyrazol-1-yl)methane ligands.6 The novel feature of these processes is that, in contrast to commonly reported procedures, the hydrogenation occurs under base-free conditions.7 1. 2. 3. 4. 5. 6. 7. F. A. Jalón, A. Otero, B. R. Manzano, E. Villaseñor, B. Chaudret, J. Am. Chem. Soc. 1995, 117, 10123–10124. (a) B. Moreno, S. Sabo-Etienne, B. Chaudret, A. Rodriguez, F. Jalon, S. Trofimenko, J. Am. Chem. Soc. 1995, 117, 7441–7451. DOI: 10.1021/ja00133a017. (b) B. Moreno, S. SaboEtienne, B. Chaudret, A. Rodriguez-Fernandez, F. Jalon, S. Trofimenko, J. Am. Chem. Soc. 1994, 116, 2635–2636. DOI: 10.1021/ja00085a060. E. Cayuela, F. A. Jalón, B. R. Manzano, G. Espino, W. Weissensteiner, K. Mereiter, J. Am. Chem. Soc. 2004, 126, 7049−7062. (a) F. A. Jalón, B. R. Manzano, A. Caballero, M. C. Carrión, L. Santos, G. Espino, M. Moreno, J. Am. Chem. Soc. 2005, 127, 15364−15365. DOI: 10.1021/ja055116f. (b) G. Espino, A. Caballero, B. R. Manzano, L. Santos, M. Pérez-Manrique, M. Moreno, F. A. Jalón, Organometallics 2012, 31, 3087−3100. dx.doi.org/10.1021/om300015j. , B. R. Manzano, A. M. Rodríguez, G. Espino, Organometallics 2012, 31, 6106−6123. dx.doi.org/10.1021/om3004702. M. C. Carrión, F. A. Jalón, B. R. Manzano, A. M. Rodríguez, F. Sepúlveda, M. Maestro, Eur. J. Inorg. Chem. 2007, 3961−3973. M. C. Carrión, F. Sepúlveda, F. A. Jalón, B. R. Manzano, A. M. Rodríguez, Organometallics 2009, 28, 3822−3833. DOI 10.1021/om9001268. Back to index Metal-Organic Supramolecular Chemistry. Study of non-covalent interactions. MOF structures and their use for gas storage. N H N N N N Me Me Me Me + AgBF4 Homochiral helix The coordination-driven self-assembly of metal-organic supramolecular architectures, including coordination polymers and metal-organic frameworks (MOFs), based on a combination of metal-ligand coordination and secondary non-covalent interactions is currently an area of great interest in inorganic crystal engineering. This interest has arisen not only because of the fascinating structures of these materials but also their potential for use in numerous applications such as gas storage and separation, ion exchange and catalysis, amongst others. In this field, we have synthesized a new type of [2×2] metallic grid that was significantly different from previously described systems. This material is able to encapsulate anions, which interact with the grid walls through non-covalent interactions. The study of these systems by diffusion NMR spectroscopy allowed us to evaluate their behaviour in solution1 (cover of Inorganic Chemistry, January 21, 2008). We also achieved internal functionalization of this system with different functional groups and this change had a clear effect on the anion hosting ability.2 Chiral grids were also obtained.3 We have also developed a set of supramolecular systems formed by self-assembly of glutarimide and triazine derivatives with multiple hydrogen bonding interactions.4 A number of ‘non-covalent’ interactions have been studied in our systems from an experimental and theoretical point of view. For example, the interplay between CH/π and anion/π interactions has been analysed in a large set of octahedral coordination compounds with tridentate ligands that were designed for this purpose.5 In addition, a singular coordination mode of a triazine-N atom, which bridges two metallic centres, has also been described.6 In our laboratory we have obtained a large number of discrete species and also one-, two- and three-dimensional coordination polymers by self-assembly of organic ligands and different metal centres7. The non-covalent interactions, which include synergistic effects, have been thoroughly analysed. Spontaneous chiral resolution in helices and sequence isomerism in coordination polymers have also been described.8 We are currently investigating MOF derivatives with covalent bonds and are assessing applications of these materials in gas storage (unpublished results). Our group was invited to write a chapter of the book Supramolecular Catalysis, which was published by Wiley in 2008.9 1. 2. 3. 4. 5. 6. 7. 8. 9. B. R. Manzano, F. A. Jalón, I. M. Ortiz, M. L. Soriano, F. Gómez de la Torre, J. Elguero, M. A. Maestro, K. Mereiter, T. D. W. Claridge, Inorg. Chem. 2008, 47, 413−428. M. I. Ortiz, M. L. Soriano, M. P. Carranza, F. A. Jalón, J. W. Steed, K. Mereiter, A. M. Rodríguez, D. Quiñonero, P. M. Deyà, B. R. Manzano, Inorg. Chem. 2010, 49, 8828−8847. M. C. Carrión, I. M. Ortiz, F. A. Jalón, B. R. Manzano, Cryst. Growth Des. 2011, 11, 1766−1776. B. R. Manzano, F. A. Jalón, M. L. Soriano, A. M. Rodríguez, A. de la Hoz, A. Sánchez-Migallón, Cryst. Growth Des. 2008, 8, 1585−1594. D. Quiñonero, P. M. Deyà, M. P. Carranza, A. M. Rodríguez, F. A. Jalón, B. R. Manzano, Dalton Trans. 2010, 39, 794−806. M. P. Carranza, B. R. Manzano, F. A. Jalón, A. M. Rodríguez, L. Santos, M. Moreno, Inorg. Chem. 2010, 49, 3828−3835. (a) B. R. Manzano, F. A. Jalón, M. L. Soriano, M. C. Carrión, P. Carranza, K. Mereiter, A. M. Rodríguez, A. de la Hoz, A. Sánchez-Migallón, Inorg. Chem. 2008, 47, 8957−8971. ( , B. R. Manzano, A. M. Rodríguez, Crystal Growth Des. 2012, 12, 1952-1969. (c) G. Durá, M. C. Carrión, F. A. Jalón, B. R. Manzano, A. M. Rodríguez. Eur. J. Inorg. Chem. 2013, “in press”. DOI: 10.1002/ejic.201300948. , A. M. Rodríguez, B. R. Manzano, Cryst. Growth Des. 2013, 13, 3275-3282. F. A. Jalón, B. R. Manzano, L. Soriano, I. Ortiz, Bis-Azolylazine Derivatives as Supramolecular Synthons for Copper and Silver [2x2] Grids and Coordination Polymers. Ch. 3 in Supramolecular Catalysis. P. W. E. N. van Leeuwen, Ed., Wiley, 2008, pp 57−91. Back to index Cytotoxicity of transition metal complexes We have started to study the cytotoxicity of platinum and arene Ru complexes containing N- or NP-donor ligands. The results clearly differ depending on the ligand and in some cases the preliminary data are very encouraging. For example, we have obtained a platinum complex that is ten times more active than cisplatin. In the case of ruthenium, a complex with the hexakis(pyrazolyl-1-yl)benzene ligand was studied previously.1 With aminophosphine ligands, IC50 values similar to those of cisplatin were obtained. Electrophoresis and AFM (Atomic Force Microscopy) studies showed good correspondence between the biological activity levels and the ability of the complex to modify the DNA structure.2 With Ruthenium-Arene-Diaminotriazine complexes, the interaction with DNA has been analysed by means of kinetics, circular dichroism, viscometry, and thermal denaturation experiments, etc.3 A stable bifunctional interaction (covalent and partially intercalated) between the CT-DNA was found in some complexes. An aquo Ru complex showed moderate selectivity towards cancer cell lines relative to healthy cells. The interaction of the complexes with DNA was studied in the Department of Physical Chemistry at the University of Burgos (B. García, J. M. Leal). We intend to continue to study the anti-proliferative activity of new complexes in an effort to establish structure-activity relationships (SAR) by comparing the results obtained for structurally related families of complexes. Likewise, we will study the possible interactions of our ‘drugs’ with DNA plasmids by means of the commonly used techniques: Atomic Force Microscopy (AFM), Electrophoresis, Fluorescence, Circular Dichroism (CD) and kinetics studies. This will provide information concerning the modification of the secondary or tertiary DNA structure. The type of interaction between our derivatives and simple models of DNA will be investigated by DFT studies and the interaction with other biotargets will also be analysed. The water solubility of the complexes will be enhanced by using the appropriately designed labile ligands. 1. 2. 3. B. R. Manzano, F. A. Jalón, G. Espino, A. Guerrero, R. M. Claramunt, C. Escolástico, J. Elguero, M. A. Heras, Polyhedron, 2007, 26, 4373−4382. C. Aliende, M. Pérez-Manrique, F. A. Jalón, B. R. Manzano, A. M. Rodríguez, J. V. Cuevas, G. Espino, M. A. Martínez, A. Massaguer, M. González-Bártulos, R. de Llorens, V. Moreno, J. Inorg. Biochem. 2012, 117, 171−188, http://dx.doi.org/10.1016/j.jinorgbio.2012.07.022. (a) N. Busto, J. Valladolid, C. Aliende, F. A. Jalón, B. R. Manzano, A. M. Rodríguez, J. F. Gaspar, C. Martins, T. Biver, G. Espino, J. M. Leal, B. García, Chem.–Asian J. 2012, 7, 788−801, DOI: 10.1002/asia.201100883. (b) N. Busto, J. Valladolid, M. Martínez-Alonso, H. J. Lozano, F. A. Jalón, B. R. Manzano, A. M. Rodríguez, M. C. Carrión, T. Biver, J. M. Leal, G. Espino, B. García, Inorg. Chem. 2013, DOI: 10.1021/ic401197a. Back to index Catalytic photogeneration of hydrogen from water using transition metal complexes Dihydrogen is currently being considered for direct combustion, for use in fuel cells with the advantage of giving rise to “clean waste products”, or for conversion into liquid fuel through the hydrogenation of various substrates. There are numerous potential hydrogen feedstocks and these include alkanes, alcohols and acids. However, water has significant advantages as it is a low energy form of hydrogen and is also the most accessible reservoir of hydrogen on the planet. An objective of major importance is thus to harness the energy of solar photons to drive the thermodynamically uphill splitting of water to produce H2 with oxygen as a byproduct (eq.1). 2H2O + hν → 2H2 + O2 (1) 2H2O(l) + 2e– H2 (g) + 2OH– (ac), E0 = –0.41 V (pH = 7) (2) 2H2O(l) O2(g) + 4H+(ac) + 4e–, E0 = +0.82 V (pH = 7) (3) Although the energy required to split water into its elemental constituents is available from sunlight, even using the more abundant and desirable visible region, the presence of a catalyst is necessary. This process is well-managed in Nature and proceeds with good efficiency but, owing to the difficulty of directing two separate multielectron redox processes, it has been very difficult to achieve success with artificial catalysts. Researchers have focused their attention on separating the overall reaction into two half reactions, thus allowing the independent study of water reduction (eq. 2) and oxidation (eq. 3). In this way, it would be possible to fine tune each reaction individually before reassembling the whole water-splitting process. It is possible to separate the two halves of the process by introducing sacrificial electron donors and acceptors. Our goal in this field concerns the catalytic photogeneration of hydrogen from water using transition metal complexes. The systems that are being used have a sunlightharvesting photosensitizer and a catalyst as the main components. This area is in its initial stages of development but our specific objectives are as follows: - - - - 1) Synthesis of new photosensitizers based on transition metal complexes and the study of their electrochemical and photophysical properties. These properties may be of interest not only in the production of hydrogen but also in other photochemical devices. 2) Obtain information about the location of the HOMO and LUMO orbitals of the new photosensitizers by carrying out DFT studies. 2) Synthesis of metal complexes those are catalytically active in hydrogen generation. 3) Design of new multicomponent systems (photosensitizers, electron relays, catalysts, sacrificial electron donors) and evaluation of their activity in the photogeneration of hydrogen using either new components obtained in our laboratory or other previously described materials. 4) Synthesis of new supramolecular assemblies that consist of a photosensitizer and a catalyst bonded through bridging ligands. Evaluation of the activity of these materials in hydrogen production. Evaluation of the effect of the type of bridging ligand. 5) Evaluation of the influence that different experimental factors (e.g. solvent, pH, ratio of components, UV cut off filter) have on the hydrogen yield in the different processes. - 6) Study of the mechanisms of the catalytic processes by spectroscopic techniques. 1. (a) A. Kudo, Y. Miseki, Chem. Soc. Rev. 2009, 38, 253 and references therein. (b) W. J. Youngblood, S.-H.A. Lee, Y. Kobayashi, E. A. Hernandez-Pagan, P. G. Hoertz, T. A. Moore, A. L. Moore, D. Gust, T. E. Mallouk, J. Am. Chem. Soc. 2009, 131, 926. (c) K. Maeda, K. Teramura, D. Lu, T. Takata, N. Sato, Y. Inoue, K. Domen, Nature 2006, 440, 295. 2. L. L. Tinker, N. D. McDaniel, S. Bernhard, J. Mater. Chem. 2009, 19, 3328.