Pascual Roman
Universidad del País Vasco UPV/EHU, Química Inorgánica, Faculty Member
- I am a university professor and researcher. I am the Head of the Inorganic Chemistry Department (Universidad del País Vasco).edit
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ABSTRACT This paper deals with the syntheses and solid state characterization of three new n-alkylammonium decavanadates with general formula (BH)6[V10O28] .2H2O, where B = n-butyl-, n-pentyl-, and n-hexylamine (hereafter abbreviated as... more
ABSTRACT This paper deals with the syntheses and solid state characterization of three new n-alkylammonium decavanadates with general formula (BH)6[V10O28] .2H2O, where B = n-butyl-, n-pentyl-, and n-hexylamine (hereafter abbreviated as BUTVA10, PENTVA10 and HEXVA10, respectively). The compounds have been prepared by dissolving V2O5 in an aqueous solution of the respective amine and adjusting the final pH to 6.0 – 6.5. The compounds have been identified by using thermoanalytical, X-ray diffraction and IR techniques. Suitable single crystals were only obtained for the hexakis(n-hexylammonium) decavanadate(V) dihydrate and its crystal structure was determined. The compound crystallizes in the monoclinic space group , M = 1605.5, a = 10.190(5), b = 18.206(4), , β = 105.35(3)°, , Z = 2, F(000) = 1656, μ = 26.75 cm−1, Dx = 1.56, Do = 1.57(1) Mg·m−3, and . Final refinement led to R = 0.058, and wR = 0.068. The unit cell is made up of decavanadate anions forming layers, n-hexylammonium cations and water molecules occupying the space among them. The distinguishing feature of this compound is its extensive hydrogen bond network which contributes to the structure stabilization. n-Butylammonium decavanadate dihydrate and n-pentylammonium decavanadate dihydrate are isostructural. Space group was determined by X-ray diffraction data. Powder diffraction patterns were indexed for a monoclinic space group unit cell, with parameters for BUTVA10: a = 16.91(2), b = 19.59(1), and β = 102.7(1)°, and for PENTVA10: a = 17.18(2), b = 20.57(2), , β = 101.7(2)°.
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The reaction of M(ox) x 2H(2)O (M = Co(II), Ni(II)) or K(2)(Cu(ox)(2)) x 2H(2)O (ox = oxalate dianion) with n-ampy (n = 2, 3, 4; n-ampy = n-aminopyridine) and potassium oxalate monohydrate yields one-dimensional oxalato-bridged metal(II)... more
The reaction of M(ox) x 2H(2)O (M = Co(II), Ni(II)) or K(2)(Cu(ox)(2)) x 2H(2)O (ox = oxalate dianion) with n-ampy (n = 2, 3, 4; n-ampy = n-aminopyridine) and potassium oxalate monohydrate yields one-dimensional oxalato-bridged metal(II) complexes which have been characterized by FT-IR spectroscopy, variable-temperature magnetic measurements, and X-ray diffraction methods. The complexes M(mu-ox)(2-ampy)(2) (M = Co (1), Ni (2), Cu (3)) are isomorphous and crystallize in the monoclinic space group C2/c (No. 15), Z = 4, with unit cell parameters for 1 of a = 13.885(2) A, b = 11.010(2) A, c = 8.755(1) A, and beta = 94.21(2) degrees. The compounds M(mu-ox)(3-ampy)(2).1.5H(2)O (M = Co (4), Ni (5), Cu (6)) are also isomorphous and crystallize in the orthorhombic space group Pcnn (No. 52), Z = 8, with unit cell parameters for 6 of a = 12.387(1), b = 12.935(3), and c = 18.632(2) A. Compound Co(mu-ox)(4-ampy)(2) (7) crystallizes in the space group C2/c (No. 15), Z = 4, with unit cell parameters of a = 16.478(3) A, b = 5.484(1) A, c = 16.592(2) A, and beta = 117.76(1) degrees. Complexes M(mu-ox)(4-ampy)(2) (M = Ni (8), Cu (9)) crystallize in the orthorhombic space group Fddd (No. 70), Z = 8, with unit cell parameters for 8 of a = 5.342(1), b = 17.078(3), and c = 29.469(4) A. All compounds are comprised of one-dimensional chains in which M(n-ampy)(2)(2+) units are sequentially bridged by bis-bidentate oxalato ligands with M.M intrachain distances in the range of 5.34-5.66 A. In all cases, the metal atoms are six-coordinated to four oxygen atoms, belonging to two bridging oxalato ligands, and the endo-cyclic nitrogen atoms, from two n-ampy ligands, building distorted octahedral surroundings. The aromatic bases are bound to the metal atom in cis (1-6) or trans (7-9) positions. Magnetic susceptibility measurements in the temperature range of 2-300 K show the occurrence of antiferromagnetic intrachain interactions except for the compound 3 in which a weak ferromagnetic coupling is observed. Compound 7 shows spontaneous magnetization below 8 K, which corresponds to the presence of spin canted antiferromagnetism.
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An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely... more
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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Related Article: U.Garcia-Couceiro, O.Castillo, J.Cepeda, M.Lanchas, A.Luque, S.Perez-Yanez, P.Roman, D.Vallejo-Sanchez|2010|Inorg.Chem.|49|11346|doi:10.1021/ic100928t
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Related Article: J.Cepeda, R.Balda, G.Beobide, O.Castillo, J.Fernandez, A.Luque, S.Perez-Yanez, P.Roman, D.Vallejo-Sanchez|2011|Inorg.Chem.|50|8437|doi:10.1021/ic201013v
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This article evaluates the strategy to design supramolecular metal–organic frameworks using metal–nucleobase entities as building units.
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Azken urteotan konposatu metal-organiko porotsuek (MOFs, metal-organic frameworks, eta SMOFs, supramolecular metal-organic frameworks ingelesez) hazkunde itzela jasan dute. Nodo ez-organikoek (atomo metaliko edo kluster metalikoz osatuta)... more
Azken urteotan konposatu metal-organiko porotsuek (MOFs, metal-organic frameworks, eta SMOFs, supramolecular metal-organic frameworks ingelesez) hazkunde itzela jasan dute. Nodo ez-organikoek (atomo metaliko edo kluster metalikoz osatuta) eta estekatzaile organikoek (molekula organikoek) eraikitzen dituzte material kristalino porotsu hauek. Estekatzaileen artean base nitrogenatuak nabarmendu ditzakegu, material metal-organiko porotsuak eraikitzeko gai baitira, bai koordinazio (MOF) zein hidrogeno-loturen (SMOF) bitartez.
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ABSTRACT A complete overview of the preparation of metal–carboxylato–nucleobase architectures that range from supramolecular assemblies to 3D porous materials is reported. The basic building units of these materials consist of... more
ABSTRACT A complete overview of the preparation of metal–carboxylato–nucleobase architectures that range from supramolecular assemblies to 3D porous materials is reported. The basic building units of these materials consist of metal–nucleobase fragments which link together through coordination bonding or by means of supramolecular assembling among the nucleobases anchored to metal centres. In the case of extended systems based on coordination bonds, the connectivity among the metal centres can be achieved through bridging nucleobases and/or by auxiliary organic linkers such as carboxylate and dicarboxylate anions. The latter bridging mode confers to the nucleobases a greater capacity to involve in molecular recognition processes with other biologically relevant species by means of the establishment of non-covalent interactions such as hydrogen bonding and/or π–π stacking among aromatic groups. On the other hand, the geometrical rigidity imposed by several metal–nucleobase fragments and the base pairing interactions through complementary hydrogen bonding, lead to structural restraints that preclude an effective filling of the space, and as a consequence, it favours the growth of tailor-made open-frameworks based either on coordination bonds (MBioFs) or on non-covalent interactions (supraMBioFs).
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The present work provides two new examples of supramolecular metal-organic frameworks consisting of three-dimensional extended noncovalent assemblies of wheel-shaped heptanuclear [Cu7(μ-H2O)6(μ3-OH)6(μ-adeninato-κN3:κN9)6](2+) entities.... more
The present work provides two new examples of supramolecular metal-organic frameworks consisting of three-dimensional extended noncovalent assemblies of wheel-shaped heptanuclear [Cu7(μ-H2O)6(μ3-OH)6(μ-adeninato-κN3:κN9)6](2+) entities. The heptanuclear entity consists of a central [Cu(OH)6](4-) core connected to six additional copper(II) metal centers in a radial and planar arrangement through the hydroxides. It generates a wheel-shaped entity in which water molecules and μ-κN3:κN9 adeninato ligands bridge the peripheral copper atoms. The magnetic characterization indicates the central copper(II) center is anti-ferromagnetically coupled to external copper(II) centers, which are ferromagnetically coupled among them leading to an S = 5/2 ground state. The packing of these entities is sustained by π-π stacking interactions between the adenine nucleobases and by hydrogen bonds established among the hydroxide ligands, sulfate anions, and adenine nucleobases. The sum of both types of sup...
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Los autores del presente proyecto tienen la intención de colaborar en la divulgación de los nombres de los elementos químicos y los términos químicos más usuales en español entre estudiantes, profesores y estudiosos amantes de la química... more
Los autores del presente proyecto tienen la intención de colaborar en la divulgación de los nombres de los elementos químicos y los términos químicos más usuales en español entre estudiantes, profesores y estudiosos amantes de la química con el objetivo de comprender mejor esta ciencia. La obra contiene la tabla periódica de los elementos químicos y la de isótopos en sus versiones más actualizadas, el prólogo de Javier García Martínez, presidente de la IUPAC, y la introducción de esta obra por los autores. Se muestran cuatro guías breves en español para la nomenclatura química de: química inorgánica, química orgánica, polímeros y terminología en polimerizaciones. Además, se incluyen dos resúmenes concisos en español de magnitudes, unidades y símbolos en química física de la IUPAC y del Sistema Internacional de Unidades, SI. El libro finaliza con el alfabeto griego. También puedes descargarlo en formato pdf en: https://dialnet.unirioja.es/servlet/libro?codigo=873818
Actas del XII Congreso de la SEHCYT