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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design and Synthesis of Gold (I) Acyclic Diamino Carbene Complexes as Metallodrugs for Cancer and for Asymmetric Catalysis

Asuramana Pedi Durayalage, Roshani 07 1900 (has links)
Many previous studies have demonstrated that gold compounds possess successful results in catalysis and in medicinal chemistry. The central aim of this dissertation is the design and synthesis of novel gold (I) acyclic diamino carbene complexes as a chemotherapeutic agent for triple-negative breast cancer (TNBC) and for catalysis. In this study, a series of chiral neutral and cationic gold (I) acyclic diamino carbene (ADC) complexes and neutral gold (I) bis- ADC complexes have been synthesized. As the chiral neutral gold (I) ADCs, four diastereomers of S binaphthyl L proline tertiary butyl ester gold (I) chloride, S binaphthyl D proline tertiary butyl ester gold (I) chloride, R binaphthyl L proline tertiary butyl ester gold (I) chloride, and R binaphthyl D proline tertiary butyl ester gold (I) chloride have been synthesized and characterized. Different chiral gold (I) ADC complexes with bulky chiral binaphthyl group and with different amine groups of morpholine, chiral proline methyl ester, and benzyl ester have been synthesized and characterized. After that four diastereomers of the nitrile adduct of cationic binaphthyl proline tertiary butyl ester nitrile and four diastereomers of the isonitrile versions of it have been synthesized and characterized. A series of gold (I) cationic bis ADC complexes have been synthesized and characterized. All these novel gold ADC complexes were tested for biological activity against TNBC cell line MDA-MB-231 and cationic S binaphthyl D proline ester isonitrile adduct, S binaphthyl D proline ester isonitrile adduct and R binaphthyl D proline ester isonitrile adduct gave promising inhibition rates. According to Lipinski's rule, lipophilicity determines the effectiveness of the drug absorption to the body through the lipid membrane. To determine the drug-likeness of the gold ADC complexes, log P values were calculated for some of the synthesized complexes using a modified shake flask method. Gold (I) ADC complexes have been renowned for their ability in catalysis, but enantioselective catalysis is not that well studied. A3 coupling reaction is a well-known reaction for the synthesis of propargyl amines. Here, A3 coupling reaction with a chiral amine has been performed using the previously synthesized four diastereomers of binaphthyl proline tertial butyl ester gold (I) ADCs (SL, RD, RL, SD) as the catalyst expecting four different diastereomers of the product. The reaction exhibited reasonable yields but with a low enantiomeric excess (ee%). However, it gave proof of the principle that asymmetric induction is possible with the synthesized novel chiral gold (I) ADC complexes.
2

A Computational Study of Palladium (II) bis(NHC) Complexes and a Computational/Experimental Study of Gold (I) bisADC Complexes Utilizing Non-Covalent Interaction for Catalysis

Tiemann, Matthew Austin 07 1900 (has links)
Carbene ligands over these years have become a heavily utilizes and effective ligand for catalysis. The diamino carbene class of ligands are slightly less understood. The effects of bis(carbene) ligand structures of palladium (II) catalysts were investigated using the ETS-NOCV method. The results showed that the amount of π-backbonding played a major role in the rate of the reaction for these NHC complexes. The amount of pi acceptance from the ligand increased in correlation to the length of the methylene linkage in the ligand back bone resulting in increased catalytic activity. The ETS-NOCV method was used to determine the deformation densities that had a contribution to this interaction based on visual interpretation. The percent contribution of pi interactions provided a linear correlation to the natural log of the initial reaction rate, indicating that π-backbonding plays a crucial role in the overall catalytic activity of the palladium complexes. Gold (I) bis acyclic diamino carbenes (ADCs) were investigated for the possibility to be strong hydrogen bond catalysts. The ligand motif of the gold (I) bisADCs were found to be analogous thiourea compounds. Based on NBO analysis there were some improvements to hydrogen bond donicity in comparison to thioureas with the same functional group. The complexes were analyzed for hydrogen bond interactions and polarizations interactions between simple nitroolefin substrate and the catalyst using ETS-NOCV. Results showed that the compounds can form a stable hydrogen bonding system and activate the substrate. This capability is tunable by changing the electron withdrawing properties of the ligase motif, providing the idea that gold (I) bisADCs have potential to be good hydrogen bond catalysts. New thiourea-like gold (I) catalysts utilizing the acyclic diamino carbene motif that were hypothesized were synthesized using a one pot synthesis approach utilizing a metal templated synthesis method. The synthesis, characterization, and application prove these complexes with their cationic centers and bisADCs ligand motif can be utilized for Friedel-Crafts alkylation of indoles, resulting in the production of three new compounds to literature. This research also provided a new application for this specific ligand class and further proved the robustness of ADC ligands.

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