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Title:Cyclopentadienyl ruthenium sulfide carbonyls and thiophene activation by iron and rhodium
Author(s):Ogilvy, Ann Elizabeth
Doctoral Committee Chair(s):Rauchfuss, Thomas B.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:The desulfurization and reduction of the sulfur-containing organic compounds in petroleum products is the objective of catalytic hydrodesulfurization (HDS), one of the largest applications of transition-metal catalysis. However, the specific mechanism for the process is not well understood. This thesis addresses certain aspects of HDS research from an organometallic perspective.
A proposed intermediate during thiophene decomposition features thiophene $\sigma$-bound through an $\alpha$-carbon to a surface metal atom. Results from the reaction of ($\rm C\sb5H\sb5$)Fe(CO)(PPh$\sb3$)(2-C$\sb4$H$\sb3$S) and methyl triflate indicate the possible formation of two S-methylated configurational isomers. The first non-mercury containing bimetallic $\mu$-thienyl compound, ((C$\sb5$H$\sb5$)Fe(CO)$\sb2$) $\sb2$(2,5-C$\sb4$H$\sb2$S) was structurally characterized.
The reaction of thiophenic compounds with Fe$\sb3$(CO)$\sb{12}$ resulted in metal insertion into the C-S bond. The known benzothiaferrole $\rm Fe\sb2(C\sb8H\sb6S)(CO)\sb6$ (1) was hydrogenated to give an insoluble iron-containing solid and a series of ethylbenzene derivatives. Oxidizing agents convert 1 to the carbonylated heterocycle thiocoumarin. $\rm Fe\sb2$(2-MeC$\sb4$H$\sb3$S)(CO)$\sb6$ desulfurizes to give the corresponding ferrole complex when heated.
$\rm \lbrack (C\sb5 Me\sb5)Rh(TMT)\rbrack\sp{2+}$ (TMT = tetramethylthiophene) reacts with cobaltocene to give the new compound ($\rm C\sb5Me\sb5)Rh(\eta\sp4$-TMT), 2. The $\eta\sp4$-TMT ligand in 2 desulfurizes upon reaction with Fe$\sb3$(CO)$\sb{12}$ to give ($\rm C\sb5Me\sb5)Rh(C\sb4Me\sb4)Fe(CO)\sb3$. An x-ray diffraction study confirms that the Fe(CO)$\sb3$ fragment is included in the $\rm C\sb4Me\sb4$ ring. The thermolysis of 2 resulted in the formation of an ionic compound. The structurally characterized cation consists of four ($\rm C\sb5Me\sb5)Rh(\eta\sp4$-TMT) "units" bound to a central rhodium atom in a square planar fashion creating a "pinwheel" structure. A new mechanism for thiophene HDS was proposed.
(($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb6$(CO)$\sb2$ eliminates SCO to give (($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb5$(CO). (($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb4$ reacts with CO to form (($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb4$(CO) (3). This is the first example of a metal-centered ligand addition to a cyclopentadienyl metal sulfide. The x-ray structure of 3 shows a $\rm Ru\sb2S\sb4$ core in a chair conformation with the bridging ($\eta\sp1$-S$\sb2$) ligands in a trans configuration. In the presence of phosphines, (($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb4$ reacts with CO to form (($\rm C\sb5Me\sb4Et)Ru$) $\sb2$S$\sb2$(CO)$\sb2$.
Issue Date:1990
Rights Information:Copyright 1990 Ogilvy, Ann Elizabeth
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9021737
OCLC Identifier:(UMI)AAI9021737

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