Nuclear magnetic resonance studies of boron trihalide complexes of 1,1-BIS (dimethylamino) ethylene and related bases

Boron tribalide complexes of 1,1-bis(dimethylamino)ethylene (DME) , t etramethylurea (TMU), tetramethylguanidine (TMG) , and pentamethylguanidine (PMG) and also mixed boron t r ihalide adducts of DME have been investigated by 1H and 19F NMR spectroscopy. Both nitrogen and the C-Q-H carbon of DME are possible donor a toms to boron trihal ides but complexation has been found to occur only at carbon of DME. The initial adduct acts as a Bronsted acid and gives up a proton to free DME in solut ion. A side reaction in the DME-BF, system gives rise to trace amounts of a complex aSSigned as (DME)2BF2+. (DME)2BF2+ is produced in much larger quantities in t he DME-BF3-BC13 and DME-BF,-BBr, systems by reaction of free DME with DME:BF2X (X = Cl, Br). Restricted r otation about the C-N bonds of TMUlBC13 and n1U:BBr3 has been observed at low temperatures. This complements previous work in this system and confirms oxygen donation of TMU to boron trihalides . Restricted rotation at low temperatures also has been observed in DMEboron trihalide systems

Estudio del (2-(Bis-(N-acetilsulfanililimino) -4 Tiazolina

Tesis (Maestría en Ciencias con Especialidad en Química Orgánica) UANL

La asistencia legal al testigo y su situación procesal en la averiguación previa (Análisis del artículo 127 Bis del Código Federal de Procedimientos Penales)

Tesis ( Maestría en Ciencias Penales) U.A.N.L.

La inconstitucionalidad del artículo 21 Bis-8 de la Ley de Hacienda para los Municipios del Estado de Nuevo León

Tesis (Maestría en Derecho Fiscal ) U.A.N.L.

Molecular Networks Created by Charge-Assisted Hydrogen Bonds Between Bis(aminidinium) Cations and Carboxylates, Sulfonates, Phosphonates and Phosphates

L'objectif de cette étude est d'apprendre à créer de nouveaux matériaux moléculaires par design. À l'heure actuelle, il n'existe aucune méthode générale pour la prédiction des structures et des propriétés, mais des progrès importants ont été accomplis, en particulier dans la fabrication de matériaux moléculaires ordonnés tels que des cristaux. En ces matériaux, l'organisation peut être contrôlée efficacement par la stratégie de la tectonique moléculaire. Cette approche utilise des molécules appelées “tectons”, qui peuvent s’associer de manière dirigée par des interactions non covalentes prévisibles. De cette façon, la position de chaque molécule par rapport à ses voisins peut être programmée avec un degré élevé de fiabilité pour créer des cristaux et d'autres matériaux organisés avec des caractéristiques et des propriétés structurelles souhaitables. Le travail que nous allons décrire est axé sur l'utilisation de l'association des cations bis(aminidinium) avec des carboxylates, sulfonates, phosphonates et phosphates, afin de créer des réseaux moléculaires prévisibles. Ces réseaux promettent d'être particulièrement robuste, car ils sont maintenus ensemble par de multiples liaisons hydrogène assistées par des interactions électrostatiques.

Two novel bis-azomethines derived from quinoxaline-2-carbaldehyde

The Schiff base compounds N,N0-bis[(E)-quinoxalin-2-ylmethylidene] propane-1,3-diamine, C21H18N6, (I), and N,N0-bis[(E)- quinoxalin-2-ylmethylidene]butane-1,4-diamine, C22H20N6, (II), crystallize in the monoclinic crystal system. These molecules have crystallographically imposed symmetry. Compound (I) is located on a crystallographic twofold axis and (II) is located on an inversion centre. The molecular conformations of these crystal structures are stabilized by aromatic pye stacking interactions.

N,N'-Bis[(E )-quinoxalin-2-ylmethylidene]ethane-1,2-diamine

In the molecule of the title compound, C20H16N6, the central C—C bond lies on a crystallographic inversion centre. The quinoxalidine ring is nearly planar, with a maximum deviation of 0.021 (2) A ˚ from the mean plane. The crystal structure is stabilized by intermolecular C—H....N interactions, leading to the formation of a layer-like structure, which extends along the a axis

Studies on the preparation of Supported nickel catalysts using bis(ethylenediamine)nickel(II) complexes as precursors

Dept.of Applied Chemistry,Cochin University of Science and Technology

Transition metal complexes of some bis(thiosemicarbazones) derived from 2,6-diacetylpyridine and N4-substituted thiosemicarbazides:Synthesis, spectral and structural studies

Coordination chemistry of pentadentate 2,6-diacetylpyridine bis(thiosemicarbazone) Schiff base ligands has been intensively studied due to the versatility of the molecular chain in order to obtain very different geometries as well as their broad therapeutic activity. Metal complexes of thiosemicarbazone with aldehydes and ketones have been widely reported. But there have been fewer reports on potential pentadentate bis(thiosemicarbazones) formed from 2,6-diacetylpyridine. Keeping these in view, we have synthesized four bis(thiosemicarbazone) systems with 2,6-diacetylpyridine. In the present work, the chelating behavior of bis(thiosemicarbazones) are studied, with the aim of investigating the influence of coordination exerts on their conformation and or configuration, in connection with the nature of the metal and of the counter ion. The selection of the 2,6-diacetylpyridine as the ketonic part was based on its capability to form polynuclear complexes with different coordination number. The doubled armed bis(thiosemicarbazones) can coordinate to a metal centre as dianionic ligand by losing its amide protons or it can coordinate as monoanionic ligand by losing its amide proton from one of the thiosemicarbazone moiety or it can also be coordinate as neutral ligand. Hence it is interesting to explore the coordinating capabilities of these ligands whether in neutral form or anionic form and to study the structural variations occurring in the ligands during complexation such as change in conformation.

Synthesis and spectral investigations of Mn(II) complexes of pentadentate bis(thiosemicarbazones)

Five Mn(II) complexes of bis(thiosemicarbazones) which are represented as [Mn(H2Ac4Ph)Cl2] (1), [Mn(Ac4Ph)H2O] (2), [Mn(H2Ac4Cy)Cl2]·H2O (3), [Mn(H2Ac4Et)Cl2]·3H2O (4) and [Mn(H2Ac4Et)(OAc)2]·3H2O (5) have been synthesized and characterized by elemental analyses, electronic, infrared and EPR spectral techniques. In all the complexes except [Mn(Ac4Ph)H2O], the ligands act as pentadentate neutral molecules and coordinate to Mn(II) ion through two thione sulfur atoms, two azomethine nitrogens and the pyridine nitrogen, suggesting a heptacoordination. While in compound [Mn(Ac4Ph)H2O], the dianionic ligand is coordinated to the metal suggesting six coordination in this case. Magnetic studies indicate the high spin state of Mn(II). Conductivity measurements reveal their non-electrolyte nature. EPR studies indicate five g values for [Mn(Ac4Ph)H2O] showing zero field splitting.

Synthesis of pendant epoxy functional polydimethyl siloxane for modification of Diglycidyl Ether of Bis-phenol A

In this study, pendant epoxy functional poly dimethyl siloxanes were synthesized by the hydrosilylation reaction of pendant silyl hydride functional polydimethyl siloxane with allyl glycidyl ether. The hydrosilylation reaction was characterized by spectroscopic techniques. Samples of pendant epoxy functional poly dimethyl siloxanes and pendant silyl hydride functional polydimethyl siloxane were blended with commercial epoxy resin, diglycidyl ether of bis-phenol A, at various ratios using a polyamine as curing agent. The results show that the addition of functionalised poly dimethyl siloxanes increases the flexibility of the cross linked network and also the thermal stability and water resistance

Bankmarketing und Jugend - Marketingmaßnahmen von Banken mit der Zielgruppe Jugendliche bis 28 Jahre unter besonderer Berücksichtigung der Sparkassen von Oberfranken und Unterfranken

Die Dissertation beschäftigt sich mit dem Jugendmarketing im Bankbereich. Es werden die verschiedenen Probleme dieser heterogenen Klientel aufgezeigt und unterschiedliche Handhabungen von Banken zur Bewältigung dieses Problems vorgestellt. Ein Schwerpunkt bildet die Untersuchung zwischen Werbeaufwand und Werbeerfolg (gemessen durch den Deckungsbeitrag) der Jugendlichen vom 1. bis 28. Lebensjahr unter besonderer Berücksichtigung der Sparkassen von Ober- und Unterfranken sowie ein Vergleich der beiden Regionen mit entsprechenden Institutsempfehlungen zur Steigerung ihres Deckungsbeitrages. Eine weitere empirische Untersuchung des Verhaltens von Jugendlichen und ihre Einstellung zur Kreditinstituten wurde mit Hilfe von Schüler- und Bankbefragungen vorgenommen.