Simple general method of generating non-oxo, non-amavadine model octacoordinated vanadium(IV) complexes of some tetradentate ONNO chelating ligands from various oxovanadium(IV/V) compounds and structural characterization of one of them

A simple general route of obtaining very stable octacoordinated non-oxovanadium( IV) complexes of the general formula VL2 (where H2L is a tetradentate ONNO donor) is presented. Six such complexes (1-6) are adequately characterized by elemental analysis, mass spectrometry, and various spectroscopic techniques. One of these compounds (1) has been structurally characterized. The molecule has crystallographic 4 symmetry and has a dodecahedral structure existing in a tetragonal space group P4n2. The non-oxo character and VL2 stoichiometry for all of the complexes are established from analytical and mass spectrometric data. In addition, the non-oxo character is clearly indicated by the complete absence of the strong nu(v=o) band in the 925-1025 cm(-1) region, which is a signature of all oxovanadium species. The complexes are quite stable in open air in the solid state and in solution, a phenomenon rarely observed in non-oxovanadium(IV) or bare vanadium(IV) complexes.

Synthesis, structural characterization and electrochemical activity of oxidovanadium(IV/V) complexes of a diprotic ONS chelating ligand

The present work reports the chemistry of a few oxidovanadium(IV) and (V) complexes of the ONS chelating ligand S-benzyl-beta-N-(2-hydroxyphenylethylidine) dithiocarbazate (H2L). Major objective of this work is to arrive at some general conclusions about the influence of binding environment generated by the replacement of an O-donor center by a S-donor point in a ligand (of a similar arrangement of the other O- and N-donor points) on the redox behavior and on the structural features of comparable [VO(OEt)(ONS)] and [VO(OEt)(ONO)] complexes. Synthesis, characterization by various physicochemical techniques (UV-Vis, IR, EPR and elemental analysis), exploration of electrochemical activity of the oxidovanadium(V) complex [(VO)-O-V(OEt) L] (1), the mixed ligand complex [(VO)-O-V(N-O)L] (3) (where N-O is the mono anion of 8-hydroxyquinoline) and a binuclear complex [(VO)-O-V(OEt)L](2)(mu-4,4'-bipy) (2) are reported. Similar studies on of mixed ligand oxidovanadium(IV) complexes of the formula [(VO)-O-V(N-N)L] (4,5) (where N-N = 2,2'-bipy and o-phen) are also presented here. The [(VO)-O-V(OEt)L] complex is pentacoordinated and distorted square pyramidal, while the [V-IV(N-N)L] complexes are hexacoordinated and octahedral. Structural features of the complex 1 were compared with the corresponding aspects of the previously reported analogous complex [(VO)-O-V(OEt)(ONO)] (1').

Agricultural statistics: Caribbean countries, vols. IV-V = Statistiques agricoles: pays de la Caraïbe, vols. IV-V = Estadísticas agrícolas: países del Caribe, vols. IV-V

Incluye Bibliografía

Obama y América Latina. En: LaRivada, V. 2, n° 2

Luego de las resistencias que George W. Bush generó en la región, la llegada de Barack Obama despertó esperanzas en algunos mandatrios latinoamericanos. En el presente artículo analizamos el vínculo entre Estados Unidos y el resto del continente, a partir del análisis de las últimas dos Cumbres de las Américas: la de Puerto España (2009), en la que primó la expectativa por la relación entre iguales que prometió el recién asumido presidente demócrata; y la de Cartagena (2012), cuando emergió una nueva agenda impuesta por América Latina, pese a las presiones de Washington. Estas cumbres se inscriben en diferentes etapas de la relación entre Estados Unidos y el resto del Hemisferio, que muestran alcances y límites de las estrategias de la Casa Blanca, y reconfiguraciones regionales para enfrentar el poder de Estados Unidos.

National Park Service concessions management : hearings before the Subcommittee on National Parks, Historic Preservation, and Recreation of the Committee on Energy and Natural Resources, United States Senate, One Hundred Seventh Congress, first session to review the National Park Service implementation of management policies and procedures to comply with the provisions of Titles I, II, III, IV, V, VI, VII, and VIII of the National Parks Omnibus Management Act of 1998, March 22, 2001, March 29, 2001.

Shipping list no.: 2001-0261-P.

Paratitla in lib. IV, V [et] VI codicis Iustiniani repetitae praelectionis /

Mode of access: Internet.

Prontuario de los tratados de paz, alianza, comercio de España hechos con los pueblos ... de Europa ... hasta el fin del reynado del señor don Phelipe V. Reynado del señor D. Phelipe IV ... : Parte IV, V, VI y VII, ultima.

Mode of access: Internet.

Librería de jueces, utilísima y universal para todos los que desean imponerse en la jurisprudencia práctica ... y en especial para abogados, alcaldes, corregidores ... : tomo VII, en que se hace resúmen ... de todas las Leyes, y Autos Acordados de que se componen los Libros IV, V y VI de la Recopilación Novisima ... de 1772, y de las anteriores y posteriores Reales Resoluciones, Cédulas, Provisiones ... desde la primitiva impresion del año de 1567 hasta el presente de 1774 /

Mode of access: Internet.