The synthesis and structural characterization of main group and transition metal complexes supported by nitrogen based ligandsShow full item record
Title | The synthesis and structural characterization of main group and transition metal complexes supported by nitrogen based ligands |
---|---|
Author | Lesikar, Leslie Anne |
Date | 2008 |
Genre | Dissertation |
Degree | Doctor of Philosophy |
Abstract | 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 ?-diketimine, ?-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.^?-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, ?-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 catalysts, the smaller ligand backbone is capable of N,N'-chelation analogously to the ?-diketiminates and ?-ketiminato ligands, as well as a variety of other coordination modes. The stoichiometric ratio of ligand to the metal alkyl was emphasized for these reactions affording aluminum and zinc formamidinate complexes exhibiting monodentate, bidentate, and bridging coordination modes. Lastly, the coordination of group 13 metal halides was investigated employing the pyridineselenolate, [HSe-2-NC5H4], and pyrazinecarboxamide, [(C4H3N2)CONH2], ligands.^The research focused on the individual synthetic methods in the preparation of group 13 complexes. |
Link | https://repository.tcu.edu/handle/116099117/4078 |
Department | Chemistry and Biochemistry |
Advisor | Richards, Anne F. |
Files in this item
This item appears in the following Collection(s)
- Doctoral Dissertations [1523]
© TCU Library 2015 | Contact Special Collections |
HTML Sitemap