7 research outputs found
Bis-qtpy (qtpy=2,2’:6’,2”:6”,2”’-quaterpyridine) metal complexes, [M(qtpy)2]2+
No full textReactions of perchlorates of iron(II), nickel(II), and zinc(II) with 2,2¢:6¢,2¢¢:6¢¢,2¢¢¢-quaterpyridine (qtpy) gave the first
crystallographically established bis-qtpy metal complexes of formula [M(qtpy)2][ClO4]2 (M ) Fe, Ni, Zn). Coordination
of two terdentate quaterpyridines to the same center produces a distorted octahedron of six nitrogen atoms around
the metal, leaving two pendant pyridyl groups, one for each quaterpyridine. For the diamagnetic zinc system, an
NMR investigation has been carried out in order to establish the conditions to obtain the intermediate mono-qtpy
complex, of formula [Zn(qtpy)(H2O)2][ClO4]2, which has also been crystallographically established. The corresponding
hexafluorophosphate derivatives [M(qtpy)2][PF6]2 (M ) Ni and Zn) were prepared in DMF at room temperature
A planar silver complex of 2,2':6',2'':6'',2'''-quaterpyridine
No full textThe silver(I) complex of 2,2’:6’,2’’:6’’,2’’’-quaterpyridine (qtpy) of formula [Ag(qtpy)][ClO4] was obtained in DMF either by reacting AgClO4 with qtpy or from a ligand redistribution between [Zn(qtpy)2][ClO4]2 and AgBF4. In the solid state the product contains mononuclear substantially planar silver-containing cations, the distances between adjacent planes being alternatively 3.39 and 3.38 Å . Pairs of cations are packed in zig-zag chains, with Ag•••Ag distances of 3.34 Å being alternated to longer ones (4.70 Å)
Proposta di metodologia semiquantitativa per la valutazione del processo di accreditamento facht-netcord di una banca di sangue cordonale
No full textProgetti di un metodo per l’analisi delle criticità strutturali e tecnologiche di un blocco operatorio
No full textBis-qtpy (qtpy = 2,2‘:6‘,2‘ ‘:6‘ ‘,2‘ ‘‘-quaterpyridine) Metal Complexes, [M(qtpy)<sub>2</sub>]<sup>2+</sup>
No full textReactions of perchlorates of iron(II), nickel(II), and zinc(II) with 2,2‘:6‘,2‘ ‘:6‘ ‘,2‘ ‘‘-quaterpyridine (qtpy) gave the first
crystallographically established bis-qtpy metal complexes of formula [M(qtpy)2][ClO4]2 (M = Fe, Ni, Zn). Coordination
of two terdentate quaterpyridines to the same center produces a distorted octahedron of six nitrogen atoms around
the metal, leaving two pendant pyridyl groups, one for each quaterpyridine. For the diamagnetic zinc system, an
NMR investigation has been carried out in order to establish the conditions to obtain the intermediate mono-qtpy
complex, of formula [Zn(qtpy)(H2O)2][ClO4]2, which has also been crystallographically established. The corresponding
hexafluorophosphate derivatives [M(qtpy)2][PF6]2 (M = Ni and Zn) were prepared in DMF at room temperature
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Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2’:6’,2’’-terpyridine ligand: implications for actinide(III) /lanthanide(III) partitioning
No full textThe quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2’:6’,2’’-terpyridine (CyMe4-hemi-BTBP) has been synthesized and its interactions with Am(III), U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UV absorption spectrophotometry, NMR studies and ESI-MS. Structures of the 1:1 complexes with Eu(III), Ce(III) and the linear uranyl (UO22+) ion were obtained by X-ray crystallographic analysis, and showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III) complex is higher. 1H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1:1 complexes with Eu(III), Ce(III) and Yb(III), while both 1:1 and 1:2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2:2 helical complexes was formed with Cu(I), with a slight preference (1.4:1) for a single directional isomer. In contrast, a 1:1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III) from Ln(III) by quadridentate N-donor ligand
Diseño de una herramienta guía para la implementación de Leanen laboratorios de educación superior
No full textThis article proposes a framework for the implementation of Lean Laboratories in higher education laboratories, which was applied in the soil and pavements laboratory of the Escuela Colombiana de Ingeniería Julio Garavito. With this framework, which incorporates in a detailed manner the steps for its application, the project aims towards decreasing the residues in these environments such as insufficient training, lack of supervision and experience, systematic performance measures, responsibility, materials availability, and generally, the absence of a systematic disposition of the laboratory and the equipment. The results achieved show important improvements in the short and medium-term in the registry and lending processes of tools and equipment. The analyzed case displays positive results with the potential of being exemplary for other organizations in the sector with aims towards implementation Lean andits tools as a functional, practical, and low-cost alternative.El artículo propone una herramienta guía para la implementación de Lean en laboratorios de educación superior, la cuál se aplicó en el laboratorio de suelos y pavimientos de la Escuela Colombiana de Ingeniería Julio Garavito. Con esta herramienta, se incorpora de manera detallada los pasos para su publicación, se busca reducir desperdicios en estos ambientes tales como un entrenamiento insuficiente, falta de supervisión, experiencia, medidas de rendimiento sistemáticas, responsabilidad, disponibilidad de materiales, y en general, la ausencia de una disposición semántica del laboratorio y del equipo. Los resultados alcanzados presentan mejoras importantes a corto y mediano plazo en los procesos de registro y préstamo de equipos y herramientas. El caso analizado evidencia resultados positivos, que tienen el potencial de servir de ejemplo para otras organizaciones del sector de la educación que deseen adaptar Lean con sus herramientas como una alternativa viable, práctica y de bajo costo
