- Mechanosynthesis of multiferroic hybrid organic-inorganic [NH4][M(HCOO)3] M = Co2+,Mn2+,Zn2+,Ni2+, Cu2+ formate-based frameworks
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The family of compounds with formula [NH4][M(HCOO)3], with M a divalent D-metal, is characterized by porous frameworks hosting NH4+ cations exhibiting at low temperature a spontaneous ferroelectric polarization. The presence of magnetically active divalent metal determines the occurrence of antiferromagnetic ordering below 30 K opening the avenue for a rational formulation of a new class of multiferroic materials. We demonstrate that this intriguing class of compounds can be synthetized with a mechanochemical approach. This novel route of synthesis was applied to the series [NH4][M(HCOO)3] with M= Cu2+, Co2+, Mn2+, Zn2+ and Ni2+ using as reactants ammonium formate and the corresponding di-hydrated metal formates. The milling duration of the process correlates with the thermal stability of the di-hydrated metal formates indicating that the first step of the mechanosynthesis process is represented by the removal of water molecules. The characterizations of the final products indicate the presence of single phase [NH4][M(HCOO)3] compounds with an excellent degree of crystallinity.
- Bersani, Danilo,Calestani, Davide,Cugini, Francesco,Gemmi, Mauro,Griesi, Andrea,Orlandi, Fabio,Righi, Lara,Solzi, Massimo,Vit, Valentina
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supporting information
(2021/12/23)
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- Metal(II) Formates (M = Fe, Co, Ni, and Cu) Stabilized by Tetramethylethylenediamine (tmeda): Convenient Molecular Precursors for the Synthesis of Supported Nanoparticles
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γ-Alumina supported 3d transition-metal nanoparticles are commonly used catalysts for several industrial reactions, such as Fischer-Tropsch, reforming, methanation, and hydrogenation reactions. However, the activity of such catalyst is often limited by the low metal dispersion and a high content of irreducible metal, inherent to the conventional preparation methods in aqueous phase. In this context, we have recently shown that [{Ni(μ2-OCHO)(OCHO)(tmeda)}2(μ2-OH2)] (tmeda=tetramethylethylenediamine) is a suitable molecular precursor for the formation of 1–2 nm large nanoparticles onto alumina. Here, we explore the synthesis of the corresponding Fe, Co, and Cu molecular precursors, namely [{Fe(μ2-OCHO)(OCHO)(tmeda)}4], [{Co(μ2-OCHO)(OCHO)(tmeda)}2(μ2-OH2)], [Cu(κ2-OCHO)2(tmeda)], which are, like the Ni precursor, soluble in a range of solvents, rendering them convenient metal precursors for the preparation of supported metallic nanoparticles on γ-alumina. Using a specific adsorption of the molecular precursor on γ-alumina in a suitable organic solvent, treatment under H2 provides small and narrowly distributed Fe (2.5±0.9 nm), Co (3.0±1.2 nm), Ni (1.7±0.5 nm), and Cu (2.1±1.5 nm) nanoparticles. XAS shows that the proportion of MAl2O4 (M = Co, Ni, Cu) is small, thus illustrating the advantage of using these tailor-made molecular precursors.
- Margossian, Tigran,Larmier, Kim,Allouche, Florian,Chan, Ka Wing,Copéret, Christophe
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- Molecularly Tailored Nickel Precursor and Support Yield a Stable Methane Dry Reforming Catalyst with Superior Metal Utilization
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Syngas production via the dry reforming of methane (DRM) is a highly endothermic process conducted under harsh conditions; hence, the main difficulty resides in generating stable catalysts. This can, in principle, be achieved by reducing coke formation, s
- Margossian, Tigran,Larmier, Kim,Kim, Sung Min,Krumeich, Frank,Fedorov, Alexey,Chen, Peter,Müller, Christoph R.,Copéret, Christophe
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p. 6919 - 6927
(2017/05/31)
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- Dinuclear and polymeric (μ-formato)nickel(II) complexes: Synthesis, structure, spectral and magnetic properties
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Two (μ-formato)nickel(II) complexes [Ni2(HCOO)(bz)8(H2O)2](HCOO)3·4H2O (1) and [Ni(tren)(HCOO)]ClO4·H2O (2) were synthesized and characterized by spectroscopic methods. The structure of complexes has been determined by X-ray crystallography. The formato ligand bridges the Ni(II) central atoms forming a dinuclear cation in 1 and a polymeric cationic chain in 2, respectively. The coordination environment of Ni(II) atom is nearly octahedral. Based upon the magnetic data, these two compounds display an exchange interaction of the antiferromagnetic nature along with the zero-field splitting. The results from magnetic analysis of 1 and 2, namely the isotropic exchange constants and the zero-field splitting parameters were further confirmed and studied by DFT method using at B3LYP/def2-TZVP and by CASSCF/NEVPT2, respectively.
- Matelková, Kristína,Bo?a, Roman,Dlháň, ?ubor,Herchel, Radovan,Moncol, Ján,Svoboda, Ingrid,Ma?lejová, Anna
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- Magnetic structure of Ni(DCOO)2(D2O)2
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Ni(HCOO)2(H2O)2 is a structurally simple coordination polymer showing interesting magnetic phase transitions at low temperature (B and 1.3 μB, and the temperature dependence of the magnetic sublattices is quite different. One of the sublattices shows the expected temperature behavior of an antiferromagnetic compound whereas the other sublattice follows a Brillouin like function with a slowly increasing magnetization below the Neel temperature.
- Jorgensen, Mads R. V.,Christensen, Mogens,Schmokel, Mette S.,Iversen, Bo B.
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p. 1441 - 1446
(2011/04/23)
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- Ordered olivine-type lithium-cobalt and lithium-nickel phosphates prepared by a new precursor method
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Single phases of olivine-type LiCoPO4 and LiNiPO4 were synthesized by thermal treatment of homogeneous lithiummetal-phosphate- formate precursors obtained by freeze drying of aqueous solutions of the corresponding metal formates and LiH2PO4. The structure, thermal behavior, and morphology of the precursors were studied by IR spectroscopy, DTA, and SEM. Cobalt and nickel phosphate-formate precursors have a composition LiMHx(PO4)(HCOO)x-yH 2O, where the formate and phosphate groups are mainly deprotonated. For the Co precursor the formate and phosphates ions are randomly coordinated to both Co and Li cations, for the Ni precursor there is a preferential coordination of the formate and phosphate ions around the Ni2+ and Li+ ion, respectively. Thermal treatment of the precursors yields single phases of olivine-type LiCoPO4 at 450 °C and LiNiPO4 at 700 °C. Structural analysis evidences that both LiCoPO4 and LiNiPO4 have an ordered olivine-type structure without any Li to M disorder between the metal positions and lithiurm deficiency. The effect of the freeze-dried solution concentration and annealing temperature on the structure, crystallite size, and morphology of LiCoPO4 and LiNiPO4 has been discussed. The morphology of the cobalt and nickel phospho-olivines comprises isometric particles with mean sizes of 190 and 380 nm, respectively.
- Koleva, Violeta,Zhecheva, Ekaterina,Stoyanova, Radostina
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p. 4091 - 4099
(2011/01/08)
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- Formation of metastable Na2CrO4-type LiNiPO 4 from a phosphate-formate precursor
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High-pressure modification of LiNiPO4 with a Na 2CrO4-type structure was obtained at ambient pressure and low temperature from a mixed LiNi-phosphate-formate precursor, LiNiPO 4Hx(HCOO)x.yH2O (where x ≈ 1.2 and y ≈ 2.5). The structural and thermal characterization of the precursor and the LiNiPO4 compositions were carried out by powder XRD analysis, IR spectroscopy, and DSC analysis, Thermal treatment of LiNiPO 4Hx(HCOO)x.VH2O precursors between 450 and 650 °C yields a mixture of the two structural modifications of LiNiPO4: the Na2CrO4 type and the olivine type, It was established that: the obtained Na2C:rO4-type LiNiPO4 is a metastable phase, which completely transforms at 700 °C into the olivine-type phase, The enthalpy of the phase transition is ?H = -43,40 kJmol-1. The mechanism of formation of the two forms of LiNiPO4 from the LiNi-phosphate-formate precursor is discussed
- Koleva, Violeta,Stoyanova, Radostina,Zhecheva, Ekaterina
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p. 127 - 131
(2010/04/01)
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- Double formates Ba2M(HCOO)6(H2O) 4 (M = Co, Ni, Cu, Zn): Crystal structures and hydrogen bonding systems
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The crystal structures of four members in the isomorphous series, Ba 2M(HCOO)6(H2O)4 (M=Co, Ni, Cu, Zn) are presented and thoroughly discussed. Discrepancies with a previous structural report on the Cu isolog [Z. Kristallogr. 110 (1958) 231] were cleared out through a re-refinement of the original data, the outcome of which definitely confirmed the present results. The strengths of the hydrogen bonds in the title compounds as deduced from the infrared wavenumbers of the uncoupled OD stretches of matrix-isolated HDO molecules are discussed in terms of the O w?O hydrogen bond lengths, the different hydrogen bond acceptor capabilities of the formate oxygen atoms and the weak Ba-OH2 interactions. The proton acceptor strength of the oxygen atoms is evaluated within the framework of the Brown's bond-valence theory. The intramolecular OH bond lengths are derived from the novel νOD vs. rOH correlation curve [J. Mol. Struct. 404 (1997) 63].
- Baggio,Stoilova,Polla,Leyva,Garland
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p. 173 - 180
(2007/10/03)
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- Synthesis of cement-containing nickel-copper catalytic systems using formic acid aqueous solutions
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Regular trends in the formation of phase composition, structure, and mechanical strength of nickel-copper catalysts used for treatment of process and off-gases were considered in relation to the concentration (5.0-60.0 wt %) of formic acid aqueous solutions used in their preparation. The optimal conditions of the preparation process were determined.
- Efremov,Tesakova,Mamaeva,Golosman
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p. 745 - 751
(2007/10/03)
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- Solubility in the Sr(HCOO)2-Ni(HCOO)2-H2O System at 25°C
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The Sr(HCOO)2-Ni(HCOO)2-H2O system at 25°C in wide concentration range is studied. The unit cell parameters of strontium formate dihydrate and nickel formate dihydrate are refined. Nickel is captured by Sr(HCOO)2*2H2O crystals through occlusion of the mother liquor.
- Fakeev, A. A.,Akhtamova, A. Sh.,Iskhakova, L. D.,Kon'kova, O. V.,Zhdanov, B. V.
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p. 679 - 681
(2008/10/08)
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