Research Areas Catalytic processes of hydrogenation, deuteration

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.