Synthesis, structure and magnetic properties of tetrakis-μ-carboxylato-bis(dodecylnicotinato)dicopper(II) complexes; crystal and molecular structure of the decyl carboxylate derivative

Dodecylnicotinate bis-adducts of binuclear copper carboxylates, of the general formula Cu2(O2CCn-1H2n-1)4(C 5H4NCOOC12H25)2, were synthesized for n = 10, 12, 14, 16, 18 and 20, and their crystal structure, thermal behavior and magnetic properties studied. The molecular structure of the decyl derivative has been determined from single-crystal X-ray diffraction data. The dimer is centrosymmetric with the CuII ions in a square-pyramidal coordination with four O-alkyl O atoms [average d(Cu - O) 1.960 (6) Å] in the basal plane and the nicotine N atom at apical positions [d(Cu - N) 2.183 (3) Å]. The copper ions, 2.615 (1) Å apart, are bridged by four O-alkyl carboxylate groups. Both the n = 20 and n = 18 homologues exhibit lamellar phases, which can be related to the supramolecular arrangement found in the n = 10 derivative. The magnetic behavior of the decyl and octadecyl dimers was studied in the 2-300 K temperature range. They exhibit a strong intramolecular antiferromagnetic interaction (Cu-Cu superexchange coupling constant J = -347 cm-1 for the decyl derivative), which can be attributed to a large overlap of the metal 3d orbitals and the oxygen lone pair orbitals of the linking carboxylate groups.Fil: Rusjan, Marcia. Universidad Nacional de General Sarmiento; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Chaia, Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Piro, Oscar Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Guillon, Daniel. Universite Paul Verlaine-Metz. Institut de Physique, Chimie et Materiaux; FranciaFil: Cukiernik, Fabio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad Nacional de General Sarmiento; Argentin

A pyrazine bis-adduct of a binuclear rhodium(II) carboxylate containing 3,4,5-triethoxybenzoate as the equatorial ligand

The title compound, tetrakis(μ-3,4,5-triethoxy­benzoato-κ2O:O′)­bis­[(pyrazine-κN)­rhodium(II)](Rh—Rh), [Rh2(C13H17O5)4(C4H4N2)2], crystallizes on an inversion centre in the triclinic space group P ‾1. The equatorial carboxyl­ate ligands bridge the two RhII atoms, giving a binuclear lantern-like structure. The pyrazine mol­ecules occupy the two axial coordination sites. The phenyl rings are tilted by ca 10° with respect to the attached carboxyl­ate groups. The pyrazine planes have a torsion angle of ca 19° around the Rh—N bond with respect to the plane of the nearer carboxyl­ate group and are not coplanar with the Rh—Rh bond.Instituto de Física La Plat

Synthesis and study of physicochemical properties, thermal stability and mesomorphic character of mono/polymeric transition metal binuclear carboxylates

El desarrollo de nuevos materiales es uno de los campos de la química en mayor expansión en la actualidad, debido principalmente a la búsqueda de compuestos con propiedades específicas para su uso en dispositivos tecnológicos. Dentro de los materiales moleculares, un área importante es la de los cristales líquidos que contienen átomos metálicos (metalomesógenos). En ese contexto, durante esta tesis se estudiaron diversas propiedades de compuestos metalomesógenos basados en carboxilatos binuclcares de metales de transición. Se puso especial énfasis en el rango térmico de existencia de las mesofases, su estructura, estabilidad térmica y procesabilidad. El trabajo abarca la síntesis, caracterización y estudio de propiedades dc polímeros de coordinación iónicos basados en carboxilatos de Ru de valencia mixta (II,III), carboxilatos no poliméricos de Cu y Os, carboxilatos pscudopoliméricos de Rh y Ru divalentes y polímeros de coordinación neutros derivados de carboxilatos de Rh y Ru divalentes puenteados por pirazina. El uso de ligandos voluminosos (aplicación del principio de llenado eficiente del espacio intermolccular) aseguró el mesomorfismo en los compuestos puenteados por pirazina, al tiempo que permitió disminuir las temperaturas de transición a la mesofase en polímeros iónicos. Se estableció la influencia de las distintas partes moleculares sobre la estabilidad térmica de algunos de esos compuestos, y sobre el rol que tienen las interacciones intermolcculares en la estabilización de las fases cristal líquido. El agregado de solvente hidrocarbonado condujo a variaciones estructurales interesantes, así como al descenso de la temperatura de transición y la viscosidad de las mesofascs. Los resultados fueron interpretados a través de modelos que consideran su arquitectura supramolecular.The development of new materials is nowadays one of the fields of Chemistry in greater expansion, mostly due to the search of compounds with specific properties for their use in technological devices. Among the molecular materials, metal containing liquid crystals (metallomesogens) are an important area. In that context, several properties of metallomesogcnic compounds based on transition metal binuclear carboxylates were studied during this thesis. Special emphasis was placed on the thermal range of existence of the mesophase, structure, thermal stability and processability. The work involves the synthesis, characterization and study of coordination ionic polymers based on mixed-valence Ru (II,III) carboxylates, non polymeric Cu and Os carboxylates, pseudo-polymeric Rh and Ru divalent carboxylates, and neutral coordination covalent polymers derived from Rh and Ru divalent carboxylates bridged by pyrazine. The use of bulky ligands (application of the principle of efficient intermolecular space filling)ensured the mesomorphism of the pyrazine bridged compounds and, at the same time, produced the lowering of the mesophasc transition temperature for the ionic polymers. The influence of the different molecular moieties on the thermal stability of some of these compounds and on the role that the intermolecular interactions play in the stabilization of the liquid crystalline phases was established. Addition of hydrocarbon solvent leads to interesting structural changes as well as to a decrease of the transition temperature and viscosity of the mesophases. The results were interpreted with models that take into account their supramolecular architecture.Fil:Rusjan, Marcia Cecilia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Synthesis, structure and magnetic properties of tetrakis-μ-carboxylato-bis(dodecylnicotinato)dicopper(II) complexes; crystal and molecular structure of the decyl carboxylate derivative

Dodecylnicotinate bis-adducts of binuclear copper carboxylates, of the general formula Cu2(O2CCn-1H2n-1)4(C5H4NCOOC12H25)2, were synthesized for n = 10, 12, 14, 16, 18 and 20, and their crystal structure, thermal behavior and magnetic properties studied. The molecular structure of the decyl derivative has been determined from single-crystal X-ray diffraction data. The dimer is centrosymmetric with the CuII ions in a square-pyramidal coordination with four O-alkyl O atoms [average d(Cu - O) 1.960 (6) Å] in the basal plane and the nicotine N atom at apical positions [d(Cu - N) 2.183 (3) Å]. The copper ions, 2.615 (1) Å apart, are bridged by four O-alkyl carboxylate groups. Both the n = 20 and n = 18 homologues exhibit lamellar phases, which can be related to the supramolecular arrangement found in the n = 10 derivative. The magnetic behavior of the decyl and octadecyl dimers was studied in the 2-300 K temperature range. They exhibit a strong intramolecular antiferromagnetic interaction (Cu-Cu superexchange coupling constant J = -347 cm-1 for the decyl derivative), which can be attributed to a large overlap of the metal 3d orbitals and the oxygen lone pair orbitals of the linking carboxylate groups.Facultad de Ciencias ExactasInstituto de Física La Plat

An unexpected carboxylato-bridged-only hexanuclear copper compound

International audienceThe reaction of copper acetate with 3,4,5-tri(ethoxy)benzoic acid leads to the formation of dodecakis((μ-(3,4,5-tri(ethoxy))benzoato-κ2O:O′)-hexa(copper(II)), [Cu6(O2CC6H2(OCH2CH3)3)12]. The new compound crystallizes in the triclinic system, space group P 1 ¯ with Z = 2, solvated by disordered cyclohexane molecules. The Cu(II) ions are placed in O5 pentacoordinated environments provided by four carboxylate oxygen atoms in a pseudo square planar arrangement and a fifth oxygen atom that belongs to a more distant carboxylate group in the axial position. The Cu(II) centers occupy the corners of a trigonal antiprism. A carboxylato network links each copper center with other four, providing potential paths for exchange coupling between the Cu(II) centers. Variable temperature magnetic susceptibility measurements show a maximum at 8 K. An analysis based on the spin-Hamiltonian formalism and DFT-based broken symmetry computations provides insight into the magnetic exchange interactions between the metal centers

Solid state modifications of drospirenone

This manuscript presents a structural, thermal and spectroscopic characterization of two different solid state forms of drospirenone (C24 H30 O3), a crystalline phase and an amorphous one. The molecule contains three fused six-membered rings and two five-membered rings; none of them is planar in character. An intra-molecular hydrogen bond was observed in the crystalline phase. Although the melting point is 202(1) °C, only very weak interactions could be considered responsible for the packing in the crystal. The amorphous phase was obtained from molten material and was found five times more soluble than the crystalline one. Infrared and Raman spectra for both phases were recorded and the vibrational properties were calculated using the GAUSSIAN 03 software package; overall agreement between calculations and experiment was obtained.Fil: Parisi, Marián Luciana. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Freire Espeleta, Eleonora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Rusjan, Marcia. Laboratorios Raffo-Monte Verde; ArgentinaFil: Moreno, Juan Marcelo. Laboratorios Raffo-Monte Verde; ArgentinaFil: Bonadeo, Hernán Aníbal. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vega, Daniel Roberto. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentin

A pyrazine bis-adduct of a binuclear rhodium(II) carboxylate containing 3,4,5-triethoxybenzoate as the equatorial ligand

The title compound, tetrakis(μ-3,4,5-triethoxy­benzoato-κ2O:O′)­bis­[(pyrazine-κN)­rhodium(II)](Rh—Rh), [Rh2(C13H17O5)4(C4H4N2)2], crystallizes on an inversion centre in the triclinic space group P ‾1. The equatorial carboxyl­ate ligands bridge the two RhII atoms, giving a binuclear lantern-like structure. The pyrazine mol­ecules occupy the two axial coordination sites. The phenyl rings are tilted by ca 10° with respect to the attached carboxyl­ate groups. The pyrazine planes have a torsion angle of ca 19° around the Rh—N bond with respect to the plane of the nearer carboxyl­ate group and are not coplanar with the Rh—Rh bond.Instituto de Física La Plat