Eurashe - Conferência do 10º Aniversário "Pan Metro Ariston"

Foi nos passados dias 26 e 27 de Maio, em Chania (Creta, Grécia), no âmbito da 10ª Conferência da Eurashe (European Association for Higher Education – uma associação europeia de instituições de ensino superior não universitário), que tive o prazer de, pela primeira vez, ouvir Sócrates Kaplanis, uma figura sui generis, de quem tinha já ouvido falar por diversas vezes, conhecida pela sua saudável irreverência e perturbante personalidade. Professor no Technological Educational Institute de Patras (Grécia), e membro fundador da Eurashe, Sócrates tem sido uma presença constante nas conferências anuais desta Associação e um elemento indispensável no reavivamento dos ensinamentos clássicos (ao mesmo tempo tão contemporâneos), não fosse ele um verdadeiro grego, até mesmo de semblante. Assim, só poderia ter iniciado a sua intervenção (tarde mas não tardia) com alguns diálogos de Platão e tê-la intitulado PAN METRON ARISTON

Two new supramolecular assemblies obtained by reaction between saccharin and long-chain diamines

The crystal structures of heptamethylenediammonium bis(saccharinate) monohydrate, [H3N-(CH2)7-NH3J(sac) 2-H2O(1) and octamethylenediammonium bis(saccharinate) hemihydrate, [H3N-(CH2)8-NH3J(sac) 2-0.5H2O(2), were determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group PI with 2 molecules per unit cell, and 2 in the mono-clinic space group P2 1/a with Z = 4. The saccharinate moiety is planar in both compounds presenting bonding characteristics comparable to those found in other saccharinate salts. The ionic crystals are fürther stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectra of the adducts are briefly discussed in comparison with those of the constituent molecules.Facultad de Ciencias ExactasCentro de Química Inorgánic

Two new supramolecular assemblies obtained by reaction between saccharin and long-chain diamines

The crystal structures of heptamethylenediammonium bis(saccharinate) monohydrate, [H3N-(CH2)7-NH3J(sac) 2-H2O(1) and octamethylenediammonium bis(saccharinate) hemihydrate, [H3N-(CH2)8-NH3J(sac) 2-0.5H2O(2), were determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group PI with 2 molecules per unit cell, and 2 in the mono-clinic space group P2 1/a with Z = 4. The saccharinate moiety is planar in both compounds presenting bonding characteristics comparable to those found in other saccharinate salts. The ionic crystals are fürther stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectra of the adducts are briefly discussed in comparison with those of the constituent molecules.Facultad de Ciencias ExactasCentro de Química Inorgánic

Mass spectrometry of 1,2,5-oxadiazole N-oxide derivatives. Use of deuterated analogues in fragmentation pattern studies

This paper reported on the study of fragmentation pattern in mass spectrometry of 1,2,5-oxadiazole N-oxide derivatives involving deuterium-labeled analogues to identify some critical fragmentations. A neutral CH2O loss from 3-hydroxymethyl-N2-oxide-4-phenyl-1,2,5-oxadiazole was confirmed with the corresponding mono-deuterated analogue. An OH loss, involving the oxygen of N-oxide, via β-H and δ-H rearrangement, was clearly revealed from 3-(4-methylpiperazine-1-ylmethyl)-N2-oxide-4-phenyl-1, 2,5-oxadiazole using the adequate tetra-deuterated analogue. N-oxide isomer and deoxygenated analogues were also used to confirm the participation of the oxide moiety in the fragmentation process.Reportamos neste trabalho o estudo sistemático de fragmentação dos derivados de N-óxidos de 1,2,5-oxadiazóis por espectroscopia de massa, usando análogos marcados com deutério para identificar algumas fragmentações críticas. Foi confirmada a perda neutra de CH2O a partir do N2-óxido de 3- hidroximetil-4-fenil-1,2,5-oxidiazol, usando o análogo mono-deuterado. A perda de OH, a partir do oxigênio do N-óxido, por um rearranjo β-H e δ-H, foi claramente verificada a partir do N2-óxido de 3-(4-metilpiperazina-1-metil)-4-fenil-1,2,5-oxidiazol, usando-se o analogo tetra-deuterado adequado. O isômero N-óxido e análogos desoxigenados foram também usados para confirmar a participação do fragmento óxido no processo de defragmentação.Facultad de Ciencias Exacta

Addition of aromatic nucleophiles to a C=N double bond of 1,2,5-thiadiazole 1,1-dioxide

A new synthesis of 3,4-diphenyl-4-aryl-1,2,5-thiadiazolines 1,1-dioxide through the addition of aromatic derivatives to 1,2,5-thiadiazole 1,1-dioxide is presented. Anhydrous AlCl3 is used as catalyst.Facultad de Ciencias Exacta

Crystallographic and theoretical studies on a coupled chain of AF binuclear Cu(II)-fluoraspirinate complexes

We present here the low temperature (116K) crystal and molecular structure of poly-[μ-pyrazine{tetrakis-fluoraspirinate-dicopper(II)}]diacetonitrile, for short [Cu(Fasp)4Cu(pyz)]n, a 5-halogenated derivative of pharmacologically relevant copper aspirinates. We also discuss the theoretically expected magnetic and thermodynamic behavior of this interesting system for molecular magnetism.Instituto de Física La Plat

Structural and spectroscopic characterization of isotypic sodium, rubidium and cesium acesulfamates

Three new acesulfamate salts, NaC4H4NO4S, RbC4H4NO4S and CsC4H4NO4S, were prepared by reactions in aqueous solutions and thoroughly characterized. Their crystal and molecular structures were determined by single crystal X-ray diffraction methods. They crystallize in the monoclinic space group P21/a with a = 7.2518(2), b = 8.9414(4), c = 10.5929(4) Å, β = 99.951(3)°, V = 676.52(4) Å3 for the Na salt; a = 7.4663(3), b = 9.6962(4), c = 10.4391(4) Å, β = 95.150(3)°, V = 752.68(5) Å3 for the Rb salt and a = 7.5995(4), b = 9.9439(4), c = 10.8814(6) Å, β = 91.298(5)°, V = 822.08(7) Å3 for the Cs salt, and Z = 4 molecules per unit cell. The three compounds are isotypic to each other and to the previously reported potassium salt. The metal ions are in irregular polyhedral coordination with six neighboring acesulfamate anions through their nitrogen and carbonyl and sulfoxide oxygen atoms. The FTIR spectra of the compounds were also recorded and are briefly discussed.Fil: 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: Echeverría, Gustavo Alberto. 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: Castellano, Eduardo Ernesto. Universidade de Sao Paulo; BrasilFil: Parajón Costa, Beatriz Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Baran, Enrique José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

Low temperature crystal structure of natural diosgenone

The molecular structure of diosgenone, a natural steroidal sapogenin, closely related to diosgenin and isolated from Solanum nudum, was solved by single crystal X-ray diffractometry at 120 K and refined by full-matrix least-squares to an agreement factor, R1 = 0.054. It crystallizes in the monoclinic space group P21, with a = 15.1870(4) Å, b = 7.2710(2) Å, c = 21.2840(6) Å, β = 99.251(1)°, and four molecules in the unit cell (Z = 4). The results constitute the first structural report on a steroidal sapogenin from the diosgenin group.Facultad de Ciencias ExactasCentro de Química Inorgánic

Transition Metal Promoted Addition of Methanol to Cyanoguanidine. Molecular Structure and Properties of the Generated Copper(II) and Nickel(II) Complexes

The reaction of the CuII and NiII complexes of saccharin with dicyandiamide (cyanoguanidine, cnge) in methanol produces the addition of methanol to the nitrile moiety of this molecule. Furthermore, the product of the reaction coordinates the metal centers generating two new complexes containing saccharinate as the counter anion. The crystal structures of [Cu(cnge-OCH3)2]-(sac)2 and of [Ni(cnge-OCH3)2](sac)2·2H2O (cnge-OCH3 = 1-amidino-O-methylurea) were solved by single crystal X-ray diffractometry. Both complexes crystallize in the triclinic space group P1 and the metallic cations present a quite similar centrosymmetric planar conformation. The complexes were characterized by means of electronic and infrared spectroscopy and also their magnetic and thermal behavior was investigated.Fil: Williams, Patricia Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Ferrer, Evelina Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Baeza, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; 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: Castellano, Eduardo Ernesto. Universidade de Sao Paulo; BrasilFil: Baran, Enrique José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

Two new supramolecular assemblies obtained by reaction between saccharin and long-chain diamines

The crystal structures of heptamethylenediammonium bis(saccharinate) monohydrate, [H3N-(CH2)7-NH3J(sac) 2-H2O(1) and octamethylenediammonium bis(saccharinate) hemihydrate, [H3N-(CH2)8-NH3J(sac) 2-0.5H2O(2), were determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group PI with 2 molecules per unit cell, and 2 in the mono-clinic space group P2 1/a with Z = 4. The saccharinate moiety is planar in both compounds presenting bonding characteristics comparable to those found in other saccharinate salts. The ionic crystals are fürther stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectra of the adducts are briefly discussed in comparison with those of the constituent molecules.Facultad de Ciencias ExactasCentro de Química Inorgánic