Synthesis, Structures and Characterization of Coordination Compounds with the Transition Metals, Ni(II), Cu(II), Mn(II), Cr(III), Fe(III), Using Ligands Based on Iminodiacetic Acid and N-heterocycles PDF Download

Author: Maria Paula Juanico
Publisher: Cuvillier Verlag
ISBN: 3865370306
Category :
Languages : en
Pages : 151

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Publisher: Cuvillier Verlag
ISBN: 3736910304
Category : Science
Languages : de
Pages : 150

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The research into supramolecular chemistry presented in tis work has resulted in the synthtesis and characterization of twenty coordination compounds. These can be considered to fall into three categories:

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Languages : en
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Nitrogen based monodentate and bidentate chelating ligands have captured a significant interest due to their ability to coordinate to a wide variety of elements. The â-diketimine, â-ketoiminato, formamidine, pyridineselenolate, and pyrazinecarboxamide ligands have all been employed in this study to further investigate the coordination preferences among main group and transition metals. Steric and electronic properties of these ligands can easily be altered by manipulating the substituents attached, thus leading to predictable structures with potential for many useful and significant applications. Investigations have shown that temperature, solvent, and metal halide employed are all key factors in the reaction outcomes. All of the complexes obtained throughout these studies have been characterized by X-ray crystallography along with other spectroscopic techniques, including NMR, IR, UV/Vis, and M/S. â-diketiminato ligands, [{N(R)C(Me)}2C(H)] where R = Dipp, Mes, commonly referred to as nacnac, have played an important role in the synthesis of novel pnictogenium complexes. Results show that through manipulation of the halide precursor, reaction stoichiometry, and the R substituent on the nacnac both N, N'- and N, C'-metal chelated complexes can be achieved. Additionally, â-ketiminato ligands, [RN(H)(C(Me))2C(Me)=O] where R = Dipp, and [RN(H)C(Me)CHC(Me)=O] where R = C2H4NEt2, have been studied. Both ligands were investigated with a range of d and p block metal halides and alkyls in order to compare and contrast the bulky, flexible, and even multi-dentate nature of each ligand. The preferred metal geometry remains constant for products with either ligand, but the steric protection offered by the individual ligands governs the nuclearity of the products, ranging from tetrameric cages to simple adducts. The formamidinate ligand, [RN(H)C(H)NR] where R = Dipp, was employed in synthesizing several aluminum and zinc complexes. In addition to their numerous applications as cata.

Author: Costisor Otilia
Publisher: World Scientific
ISBN: 9814482889
Category : Science
Languages : en
Pages : 307

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This book surveys the relatively new area of the synthesis of organic ligands when metal ions act as a template. In the last fifty years this field has undergone an explosive development, marked by a great amount of literature. The material in the book has been arranged according to the type of chemical reaction involved. In this frame, the basic principles of metal template reactions and the shape of the molecules are considered. Designed to satisfy the demands of students, young researchers doing their PhDs, and those working in the field of coordination chemistry, the book details the role of the metal ions and the specific properties of the formed complexes.Metal Mediated Template Synthesis of Ligands offers a comprehensive analysis with wide-ranging references and provides an extensive overview of research on metal-directed organic ligands over the past five decades.

Author: Sali Nabeel Hanna Jabrou
Publisher:
ISBN:
Category : Actinide elements
Languages : en
Pages : 191

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Over recent years a great deal of interest has developed in new transition metal complexes of Schiff base ligand. The preparation of new ligand is the most important step in the development of metal complexes that exhibit unique properties and novel reactivity. The electron donor and electron acceptor properties of the ligand, the structural function groups and the position of the ligand in the coordination sphere, together with the reactivity of coordination compounds may be the factor for different studies. The synthesis and structural investigations of Schiff bases and their metal complexes are a considerable center of attention because of their potentially beneficial pharmacological properties and a wide variation in their mode of bonding. Metal coordination complexes have a wide variety of technological and industrial application, ranging from catalysis to anticancer drugs. In these compounds the metal atom itself may have a number of roles, based on its coordination geometry, oxidation state, and magnetic electronic and photochemical behaviors. This study presents the synthesis, characterization, and structural studies of different series of Copper and Uranium complexes of salicylaldehyde Schiff base derivatives with various organic amine compounds. The Schiff bases act as neutral and bidentate ligands, which can attach the metal through the azomethine nitrogen and furfural oxygens. These Schiff bases are prepared by iii reacting salicylaldehyde with various organic amines. In the case of most complexation reactions, highly colored precipitates were formed immediately. The complexes were found to have composition ML2 and M2L2, where M is the metal and L the organic ligand. This implies "mononuclear" structures with one metal + 2 ligands, and "binuclear" where the ligands hold two metal atoms in close proximity. The interesting molecular and crystal structural features of the Schiff base ligand called E-2-((benzo[d]thiazol-2-ylimino)methyl)phenol and its Cu(II) complex are presented in Chapter 2. Further investigations on the coordination chemistry of the Schiff base ligands are made by reacting these ligands with copper and uranium, described in Chapter 3. Another series of dicopper(II) complexes and diuranium complex of the Schiff base ligands, containing azomethine nitrogen and furfural oxygen donor group are investigated to evaluate the role of alkoxo bridge on the structures. Making the compounds with two uranium atoms leads to very high molecular weight, as a path to the highest molecular weight liquid crystal. This lays the pathway to future work for making those crystals. These dinuclear complexes are presented in chapter 4. The objective of the present study is to investigate the coordination chemistry of these ligands with Copper and Uranium. For the ligands this was done by a combination of nuclear magnetic resonance spectroscopy, infrared spectroscopy, ultraviolet-visible spectroscopy and single X-ray crystallography. The metal complexes were analyzed by the same techniques, except that in the case of uranium, all efforts to obtain single crystal for X-ray crystallography proved unsuccessful, so the molecular structure had to be ascertained from the other techniques.

Author: Sarah Ouanounou
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Joanna Czuchajowska-Wiesinger
Publisher:
ISBN:
Category : Transition metal complexes
Languages : en
Pages : 362

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Category :
Languages : en
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Author: Ashleigh Lauren Ward
Publisher:
ISBN:
Category :
Languages : en
Pages : 113

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Chapter 1: A series of actinide-transition metal heterobimetallics have been prepared, featuring thorium, uranium and cobalt. Complexes incorporating the binucleating ligand N[o-(NHCH2PiPr2)C6H4]3 with either Th(IV) (1.4) or U(IV) (1.5) and a carbonyl bridged [Co(CO)4]- unit were synthesized from the corresponding actinide chlorides (Th: 1.2; U: 1.3) and Na[Co(CO)4]. Irradiation of the resulting isocarbonyls with ultraviolet light resulted in the formation of new species containing actinide-metal bonds in good yields (Th: 1.6; U: 1.7); this photolysis method provides a new approach to a relatively unusual class of complexes. Characterization by single-crystal X-ray diffraction revealed that elimination of the bridging carbonyl and formation of the metal-metal bond is accompanied by coordination of a phosphine arm from the N4P3 ligand to the cobalt center. Additionally, actinide-cobalt bonds of 3.0771(5) Å and 3.0319(7) Å for the thorium and uranium complexes, respectively, were observed. The solution-state behavior of the thorium complexes was evaluated using 1H, 1H-1H COSY, 31P and variable-temperature NMR spectroscopy. IR, UV-vis/NIR, and variable-temperature magnetic susceptibility measurements are also reported. Chapter 2: The first examples of actinide complexes incorporating corrole ligands are presented. Thorium(IV) and uranium(IV) macrocycles of Mes2(p-OMePh)corrole were synthesized via salt metathesis with the corresponding lithium corrole in remarkably high yields (93% and 83% respectively). Characterization by single-crystal X-ray diffraction revealed both complexes to be dimeric, having two metal centers bridged via bis([mu]-chlorido) linkages. In each case, the corrole ring showed a large distortion from planarity, with the Th(IV) and U(IV) ions residing unusually far (1.403 Å and 1.330 Å respectively) from the N4 plane of the ligand. 1H NMR spectroscopy of both the Th and U dimers revealed dynamic solution behavior. In the case of the diamagnetic Th corrole, variable-temperature, DOSY and EXSY 1H NMR spectroscopy was employed, and supported that this behavior was due to an intrinsic pseudorotational mode of the corrole ring about the M-M axis. Additionally, the electronic structure of the actinide corroles was assessed using UV-visible spectroscopy, cyclic voltammetry and variable-temperature magnetic susceptibility. This novel class of macrocyclic complexes provides a rich platform in an underdeveloped area for the study of non-aqueous actinide bonding and reactivity. Chapter 3: A series of divalent first row triflate complexes supported by the ligand tris(2-pyridyl(methyl))amine (TPA) have been investigated as oxygen reduction catalysts for fuel cell applications. [(TPA)M2+]n+ (M= Mn, Fe, Co, Ni and Cu) derivatives were synthesized and characterized by X-ray crystallography, cyclic voltammetry, NMR spectroscopy, magnetic susceptibility, IR spectroscopy and conductance measurements. The stoichiometric and electrochemical O2 reactivity of the series were examined. Chapter 4: Complexes of the ligand tris(2-pyridyl(methyl))amine (TPA) {[(TPA)M2+]n+ (M= Mn, Fe, Co and Cu)} presented in chapter 3 were evaluated as electrocatalysts for oxygen reduction. Rotating-ring disk electrode (RRDE) voltammetry was used to examine the catalytic activity of the series of complexes on a carbon support in acidic media, emulating fuel cell performance. The iron complex displayed a selectivity of 89% for four-electron conversion and demonstrated the fastest reaction kinetics, as determined by a kinetic current of 7.6 mA. Additionally the Mn, Co and Cu complexes all showed selective four-electron oxygen reduction (

Author: Eugene James Peterson
Publisher:
ISBN:
Category : Coordination compounds
Languages : en
Pages : 758

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