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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

ORGANOMETALLIC HETEROCYCLES AND ACENE-QUINONE COMPLEXES OF RUTHENIUM, IRON AND MANGANESE

Pokharel, Uttam Raj 01 January 2012 (has links)
A variety of organometallic-fused heterocycles and acene quinones were prepared and characterized. This work was divided into three parts: first, the synthesis of 5,5-fused heterocyclic complexes of tricarbonylmanganese and (1’,2’,3’,4’,5’-pentamethylcyclopentadienyl)ruthenium; second, the synthesis of 1,2-diacylcyclopentadienyl p-cymene complexes of ruthenium(II); and third, synthesis of cyclopentadienyl-fused polyacenequinone complexes of ruthenium, iron and manganese. The first examples of the convenient, versatile and symmetric cyclopentadienyl-fused heterocycle complexes of (1’,2’,3’,4’,5’-pentamethylcyclopentadienyl)ruthenium(II) and tricarbonylmanganese(I) were synthesized starting from (1,2-dicarbophenoxycyclopentadienyl)sodium. The sodium salt was transmetalated using [MnBr(CO)5] and 1/4 [Ru(μ3-Cl)(Cp*)]4 to give [Mn(CO)3{η5-C5H3(CO2Ph)2-1,2}] and [Ru{η5-C5H3(CO2Ph)2-1,2}(Cp*)]. The diester complexes were saponified under basic conditions to obtain the corresponding dicarboxylic acids. The dicarboxylic acids were used to synthesize unique cyclopentadienylmetal complexes including diacyl chlorides, anhydrides, thioanhydrides and p-tolyl imides of ruthenium and manganese. Similarly, a series of 1,2-diacylcyclopentadienyl-p-cymene cationic complexes of ruthenium were synthesized using thallium salt of 2-acyl-6-hydroxyfulvene and [Ru(η6-p-cymene)(μ-Cl)Cl]2 in a 2:1 ratio with an intension of converting them into heterocycle-fused cationic sandwich complexes. However, our attempts of ring closing on 1,4-diketons with sulfur or selenium were unsuccessful. A methodology involving the synthesis of metallocene-fused quinone complexes was employed starting from pentamethylruthenocene-1,2-dicarboxylic acids. The diacyl chloride was prepared in situ from the dicarboxylic acids and used for Friedel-Crafts acylation. We observed single-step room-temperature diacylation of aromatics, including benzene, o-xylene, toluene, 1,4-dimethoxybenzene and ferrocene with pentamethylruthenocene-1,2-diacyl chloride to obtain the corresponding quinone complexes. Similarly, we synthesized mononuclear and binuclear γ-quinones by aldol condensation of 1,2-diformylcyclopentadienylmetal complexes with cyclohexane-1,4-dione or 1,4-dihydroxyarenes. The third methodology involves the Friedel-Crafts acylation of ferrocene with 2-carbomethoxyaroyl chlorides followed by saponification, carbonyl reduction, and ring closing by second Friedel-Crafts acylation to give Ferrocene-capped anthrone-like tricyclic and tetracyclic ketones. The oxidation of the ketones gave [3,4-c]-fused α-quinone complexes of iron. The oxidative and reductive coupling, enolization and C-alkylation of the anthrone complex were studied. Solvolysis of α-carbinol gave α-ferrocenylcarbenium salt, which underwent dimerization on treatment with non-nucleophilic base. We were successful to trap the in situ generated trimethylsilylenol ether of ferrocene-anthrone using dienophiles like N-phenylmaleimide or dimethylacetylenedicarboxylate under Diels-Alder conditions.

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