Keywords : Solid state and soft chemistry syntheses; Physical property studies (operando reactivity, characterization in used-conditions, …)
- Reactivity in used-conditions.
- RX analysis: diffraction/total scattering & spectroscopies.
- NMR studies One goal of our research is to understand cooperative effects between local and average structures.
Transition metal oxide
Transition metal oxides and energy conversion
Our activities over the period 2015-2019 were mainly articulated around three distinct topics: continuation of the themes (i) fuel cells and (ii) oxyhydride chemistry (collaboration with Pr. H. Kageyama, Univ. Kyoto, Japan), both based on perovskite-derived materials. In addition, the theme (iii) multiferroic oxides was initiated and developed in particular through a new collaboration with Prof. K. Fujita (Univ. Kyoto, Japan) partly involving X. Rocquefelte of the CTI team at ISCR. A common denominator is the use of large scale facilities (neutron sources and synchrotron) for advanced crystal chemistry analyzes, often coupled with computational chemistry calculations. The highlights are summarized below.
- (i) We have revisited by in situ synchrotron X-ray diffraction on powder and thermogravimetric analyzes the structural properties and chemical reactivity of the cathode material Pr2NiO4+d under high partial pressure of oxygen in collaboration with the ICMCB (J.-M. Bassat et al.) .
- (ii) The lability of the hydride ligand in BaTiO3-xHx oxyhydride that we discovered in 2012 has been demonstrated and exploited through low-temperature multistage topotactic syntheses leading to novel mixed anion compounds . Note that a guest journal article  attests to the importance of collaboration between the CSM team and Kyoto University in this area. The influence of the layer topology and the nature of the B-site cation in Ruddlesden-Popper oxyhydrides has recently been investigated .
- (iii) High pressure / high temperature syntheses combined with the use of small cations at A site have afforded the new rhombohedral perovskite InFeO3, polar and ferromagnetic at ambient conditions . The phenomenon of hybrid improper ferroelectricity has been exploited in the Sr3Zr2O7n = 2 Ruddlesden-Popper phase  while a universal relationship has been established between the Curie temperature and the Goldschmidt tolerance factor in these A3B2O7 oxides .
 T. Broux, C. Prestipino, M. Bahout, S. Paofai, E. Elkaïm, V. Vibhu, J.-C. Grenier, A. Rougier, J. M. Bassat, O. Hernandez, Dalton Transactions, 2016, 45, 3024-3033
 N. Masuda, Y. Kobayashi, O. Hernandez, T. Bataille, S. Paofai, H. Suzuki, C. Ritter, N. Ichijo, Y. Noda, K. Takegoshi, C. Tassel, T. Yamamoto, H. Kageyama, Journal of the American Chemical Society, 2015, 137, 15315-15321
 Y. Kobayashi, O. Hernandez, C. Tassel, H. Kageyama, Science and Technology of Advanced Materials, 2017, 18, 905-918
 O.J. Hernandez, G. Geneste, T. Yajima, Y. Kobayashi, M. Okura, K. Aidzu, C. Tassel, S. Paofai, D. Swain, C. Ritter, H. Kageyama, Inorganic Chemistry, 2018, 57, 11058-11067
 K. Fujita, T. Kawamoto, I. Yamada, O. Hernandez, N. Hayashi, H. Akamatsu, W. Lafargue-Dit-Hauret, X. Rocquefelte, M. Fukuzumi, P. Manuel, A.J. Studer, C. S. Knee, K. Tanaka, Chemistry of Materials, 2016, 28, 6644-6655
 S. Yoshida, K. Fujita, H. Akamatsu, O. Hernandez, A.S. Gupta, F.G. Brown, H. Padmanabhan, A.S. Gibbs, T. Kuge, R. Tsuji, S. Murai, J.M. Rondinelli, V. Gopalan, K. Tanaka, Advanced Functional Materials, 2018, 28, 1801856
 S. Yoshida, H. Akamatsu, R. Tsuji, O. Hernandez, H. Padmanabhan, A.S. Gupta, A.S. Gibbs, K. Mibu, S. Murai, J.M. Rondinelli, V. Gopalan, K. Tanaka, K. Fujita, Journal of the American Chemical Society, 2018, 140, 15690-15700 (2018)
Oxoanions based compounds synthesis
Our activity concerning oxoanions is focused on sulphates, borates and phosphates, mainly in the continuity of the activities developed in the previous contract. The work carried out on the first two families is based on well-established collaborations with Tunisia (University of Sfax) and Chile (LIA M3). This research consists in synthesis work by soft chemistry (co-precipitation, hydro / solvo-thermal synthesis) and structural and physicochemical characterizations, with the aim of elucidating
For example, the structure and reactivity of three related 1DNi-phosphinate CPs have been studied and transformations of 1D coordination compounds in 3D ones induced by the temperature have been elucidated. We can say that these structures can be considered as sort of proto-coordination polymers able to afford novel 3D structures upon heating which cannot be obtained by direct synthesis.
Another example is the discovery of the First Non-Centrosymmetric Deca-Vanadoborate with borate vacancies, self-assembled around a 1,3-propanediammonium cation
The compound of formula (H2PDA2+)5 [H2PDA2+@V10B24O66H8] 13.23H2O with an occluded 1,3-propanediammonium cationin a decavanadate V10B24O66H8, is reported. This cluster lacks four borate units with respect to all known deca-vanadoborates. leading to the first non-centrosymmetric deca-vanadoborate reported in the literature. The electronic properties were studied using electronic spectroscopy, corroborating a fully reduced species, due to the lack of intervalence charge transfer transitions in the 1000 to 1500 nm region. The magnetic behavior provided evidence that the studied cluster presents strong antiferromagnetism among the ten VIV spin-carriers, with an S= 0 ground state. Using a model considering three different exchange pathways, three different J values were obtained, all of them antiferromagnetic in nature.
Vanadium phosphates: multiscale characterization by combining X-ray powder diffraction and solid state NMR
Work on phosphates (mainly vanadium phosphates, VPO) focused on the structural characterization of different classes of VPOs: Those used industrially in heterogeneous catalysis for the production of maleic anhydride from butane and VPOs for Li and Na batteries.
i) VPOs for the conversion of butane into maleic anhydride
The purpose of this work is to understand the behaviour of the material under conditions of use: phase transitions, mobility / diffusion of ions in relation to reactivity. This activity took place mainly within the framework of the ANR "Blanc" MOSAIC (coll. LCS Caen and UCCS Lille).
A new vanadyl oxalatophosphite, (NH4)2(VOHPO3)2C2O4 2.9 H2O has been prepared, its structure solved by single-crystal X-ray diffraction and confirmed by 31P and 1H solid state NMR.The elaboration of new synthetic pathways to the catalytic phase has been studied.
Thermogravimetric studies and Variable Temperature X-ray diffraction evidenced that after the oxidation of phosphite into phosphate a precise control of the atmosphere gives the possibility to prepare two different catalytically active materials: on the one hand V4+ is oxidized to V5+ under air and consequently w-VOPO4 is the stabilized phase at 430°C; on the other hand under nitrogen V4+ remains stable and (VO)2(P2O7) crystallizes at 570°C.
manuscript which won the 2018 thesis prize from the AFC in chemistry. In parallel, we have developed an activity focusing on the study of local order and dynamics (rotational and translational) in materials, by combining high resolution solid-state NMR techniques, variable-temperature NMR and NMR with pulsed field gradient. This activity is developed locally with, for example, the establishment of specific NMR sample environments (pressure, temperature) and in collaboration with IR-NMR (FR CNRS 2950).We worked with LCS researchers for in situ solid-state NMR studies. As part of this work, methodological developments in solid state NMR were carried out in collaboration with the Lille UCCS and the team of Prof. Ashbrook (St Andrews, CRCT L. Le Pollès). These developments were implemented in Rennes for the local characterization of the different VPO phases. In this context, the group has equipped itself with an RX powder diffractometer mainly dedicated to in situ / operando measurements under reactive atmospheres. The various sources of funding have enabled us to develop a sample environment system ensuring a high-pressure gas flow equivalent to industrial fluidized bed systems and up to around 1000° C. We have also produced a gas distribution board using programmable micro-flowmeters. The first results obtained during C. Kouvatas’s thesis are part of the
ii) VPOs for Li and Na Batteries
We employed a combination of solid-state NMR spectroscopy and X-ray diffraction to get a better understanding of the lithium intercalation in a layered vanadium phosphate compound. Detailed 7Li NMR experiments carried out for a fifty percent lithium intercalation compound showed a series of discrete local environments for the lithium ions. Beyond the structural description of the lithium intercalation local ordering, this work allowed us to describe the dynamics of the interlayer species at very different timescales. We were able to demonstrate a decrease of the exchange between sites during the ageing of the intercalated compound. Our experiments allowed to evidence a charge ordering between VOPO4 layers mechanism taking place on a time scale of at least several days and correlated with the existence of a millisecond time scale exchange between the lithium sites on a local scale.
Starting from the composites based on the MnPS3 (M = Cd, Mn) matrix it is possible to obtain by microwave synthesis, as an alternative to the usual ceramic route, a series of layered bimetallic thiophosphates with various compositions: i) M'0.2Mn0.8PS3∙0.25H2O (M' = CoII, NiII, CuII, ZnII), in which insertion between the cation sheets generates gaps within the sheets and spontaneous magnetization with antiferromagnetic interactions; ii) M0.25Cd0.75PS3(M = ZnII,NiII,CoII,MnII) possessing an ordered distribution of the substituent cations with antiferromagnetic behavior for phases with MnII, CoII and NiII and in which the conductivity is attributed to charge movements in the layers; iii) Ni2xMn2-2xP2S6 phases with an absorption edge of the solid state UV-visible spectra shifted to lower energies as the percentage of nickel(II) increased. In all these studies, the combination of structural and microstructural analyses from powder XRD data with the magnetic (SQUID) and spectroscopic (EPR, UV-visible impedance) properties resulted in the rationalization of the magnetic and optical properties.
This project is carried out within the framework of the international laboratory associated with Chile, University UNAB at Santiago (LIA MIF and LIA M3).
Heterocyclic systems for magnetic, biological and catalytic studies
Heterocyclic compounds (terpyridine tpy derivatives) and their complexes with transition and lanthanide ions as paramagnetic centers have been studied in collaboration with groups in Chile (Santiago, Viña del Mar, Valparaiso, Concepcion). They constitute quite innovative models in the field of molecular magnetism and may present different behaviors, from paramagnetism to ferromagnetism depending, among others, on the cation oxidation state (mixed valence), geometry (e.g., planarity), etc., as we have shown in several works concerning Cu(II) and Co(II) ions , . The role of the organic ligands is absolutely essential to coordinate hard and soft metal ions to obtain stable systems; for this, a systematic study (spectroscopic, TD-DFT, thermal stability, etc.) was developed on four terpyridine ligands, as shown in . A phenomenological model based on a significant orbital contribution allowed interpreting the magnetic properties of cobalt complexes  and has been extended to other transition metal complexes. Lately, interesting magnetic and physical properties such as a spin-crossover phenomenon with reversible changes between low-spin and high-spin states, changes on the crystal structure and optical properties, has been studied in Mn(III) complexes, in relation with remarkable thermochromic properties .
 Unusual trinuclear complex of copper(II) containing a 4’-(3-methyl-2-thienyl)-4,2’:6’,4”-terpyridine ligand. Structural, spectroscopic, electrochemical and magnetic properties
D. Toledo, G. Ahumada, C. Manzur, T. Roisnel, O. Peña, J.-R. Hamon, J.-Y. Pivan, Y. Moreno
J. Molec. Struct., 2017, 1146, 213-221. http://dx.doi.org/10.1016/j.molstruc.2017.05.108
 New cobalt(II) coordination polymer based on carboxyphenyl-tpy ligand : photoluminescence, crystal structures and magnetic properties, without orbital contribution
D. Toledo, O. Peña, T. Roisnel, J.-Y. Pivan, Y. Moreno
J. Coord. Chem., 2018, 71. https://doi.org/10.1080/00958972.2018.1425800
 Influence of structural changes on photophysical properties of terpyridine derivates: Experimental studies and theoretical calculations
D. Toledo, F. Brovelli, J. Soto-Delgado, O. Peña, J.-Y. Pivan, Y. Moreno
J. Molec. Struct., 2018, 1153, 282-291. https://doi.org/10.1016/j.molstruc.2017.10.011
 Synthesis, crystal structure and magnetic properties of diaquabis(2,6-diamino-7H-purin-1-ium-κN9)bis(4,4′-oxydibenzoato-κO)cobalt(II) dehydrate
A.M. Atria, J. Parada, Y. Moreno, S. Suarez, R. Baggio, O. Peña
Acta Cryst. C (2018) 74, 37-44. https://doi.org/10.1107/S2053229617016916
 Structural studies of a manganese(III) complex with spin-crossover and thermochromic properties”.
D. Villaman, Ch.J. McMonagle, M.R. Probert, O. Peña, Y. Moreno, M. Fuentealba.
CrystEngComm., 2020, 22, 3221-3233. DOI : 10.1039/c9ce01962f
Cooperative magnetic effects in oxide materials
Previous works on magnetic perovskites (coll. Spain), largely presented in one of our earliest reviews on the subject  have been extended to ternary systems BiFeO3-BiMnO3-PbTiO3, designed to show multiferroic properties with room-temperature magnetoelectricity  or, recently, to the study of morphotropic phase boundaries in the ternary system YMnO3-BiFeO3  prepared by mechanosynthesis and/or followed by spark-plasma sintering . Other aspects of our research (coll. Chile) concerned spinel-type magnetochalcogenides in which magnetic interactions, from long-range order to spin-glass and frustrated states, may coexist. This has been shown on our works on CuCr2 xMxSe4 (M = Sn, Zr and Ti) and Cu[Cr2−xSnx]S4−ySey materials , , and it is presently extended to Co-based compounds.
The catalytic performance of lanthanum manganites , the magnetic properties of nanostructured materials prepared in organic solvents  or from macromolecular precursors , lanthanide oxychalcogenides prepared by solid-state , have been extensively studied in collaboration with several universities in Chile (Santiago, Concepcion, Antofagasta) or at New Dehli (India). Other aspects of our research are devoted to the study of nanomaterials of high purity prepared by soft chemistry such as the Polyol Method, in which ferro- and anti-ferromagnetic interactions may coexist, as it is the case of cobalt-oxides partially substituted by transition metals, in which the oxidation state of the metal cations depends on the crystallographic site occupied in the spinel-type structure  (coll. Brazil).
 C. MOURE, O. PEÑA – “Recent Advances in Perovskites : processing and properties”. Review Article. Prog. Solid State Chem., 2015, 43, 123-148. http://dx.doi.org/10.1016/j.progsolidstchem.2015.09.001
 C.M. FERNANDEZ-POSADA, A. CASTRO, J.-M. KIAT, F. PORCHER, O. PEÑA, M. ALGUERO, H. AMORIN – “A novel perovskite oxide chemically designed to show multiferroic phase boundary with room-temperature magnetoelectricity”. Nature Communic., 2016, 7, 12772 DOI: 10.1038/ncomms12772
 M. ALGUERO, J.A. QUINTANA-CILLERUELO, O. PEÑA. A. CASTRO. “Magnetic properties across the YMnO3-BiFeO3 system designed for phase-change magnetoelectric response”. Mater. Science & Engin. B, 2021, 266, 115055. https://doi.org/10.1016/j.mseb.2021.115055
 J.A. QUINTANA-CILLERUELO, A. CASTRO, H. AMORIN, V.K. VEERAPANDIYAN, M. DELUCA, O. PEÑA, M. ALGUERO. “Ceramic processing and multiferroic properties of the perovskite YMnO3-BiFeO3 binary system”. J. Am. Ceram. Soc., 2020, 103, 4846-4858. https://doi.org/10.1111/jace.17211
 S. MORIS, P. VALENCIA-GALVEZ, J. MEJIA-LOPEZ, O. PEÑA, P. BARAHONA, A. GALDAMEZ, “(Cu)tet(Cr2-xSnx)octS4-ySey spinels : crystal structure, density functional theory calculations and magnetic behavior”. Inorg. Chem., Inorg. Chem. 58 (2019) 13945-13952. DOI : 10.1021/acs.inorgchem.9b01853 and “Correction to (Cu)tet(Cr2-xSnx)octS4-ySey spinels : crystal structure ….”, Inorg. Chem., 2020, 59, 5242 5242. https://dx.doi.org/10.1021/acs.inorgchem.0c00662
 C. PINTO, A. GALDAMEZ, P. BARAHONA, S. MORIS, O. PEÑA – “Crystal structure, Raman scattering and magnetic properties of CuCr2-xZrxSe4 and CuCr2-xSnxSe4 selenospinels”. J. Magn. Magn. Mater., 2018, 456, 160-166. https://doi.org/10.1016/j.jmmm.2018.02.023
 R. DINAMARCA, C. SEPULVEDA, E.J. DELGADO, O. PEÑA, J.L.G. FIERRO, G. PECCHI – “Electronic properties and catalytic performance for DME combustion of lanthanum manganites with partial B-site substitution”. J. Catalysis, 2016, 338, 47-55. http://dx.doi.org/10.1016/j.jcat.2016.02.011
 G. CARDENAS, O. GODOY, Y. MORENO, O. PEÑA – “Samarium colloids prepared in organic solvents and active solids”. Colloid Polym. Sci., 2016, 294, 2109-2119. DOI 10.1007/s00396-016-3950-3
 C. DIAZ, M.L. VALENZUELA, M.A. LAGUNA-BERCERO, A. ORERA, D. BOBADILLA, S. ABARCA, O. PEÑA – “Synthesis and magnetic properties of nanostructured metallic Co, Mn and Ni oxide materials obtained from solid-state metal-macromolecular complex precursors”. RSC Adv., 2017, 7, 27729-27736. DOI: 10.1039/c7ra00782e
 S. GAUTAM, K.H. CHAE, J. LLANOS, O. PEÑA, K. ASOKAN. “Elecronic structure of Ln2O2Te (Ln = La, Sm and Gd) by X-Ray Absorption spectroscopy”, Vacuum, 2018, 158, 39-41. https://doi.org/10.1016/j.vacuum.2018.09.008
 M.E. dos SANTOS, R.A. FERREIRA, P.N. LISBOA-FILHO, O. PEÑA – “Cation distribution and magnetic characterization of the multiferroic cobalt manganese Co2MnO4 spinel doped with bismuth”. J. Magn. Magn. Mater., 2013, 329, 53-58. http://dx.doi.org/10.1016/j.jmmm.2012.09.070