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Title:The synthesis and stereodynamics of cyclopentadienyl ruthenium chalcogenide clusters
Author(s):Houser, Eric Jon
Doctoral Committee Chair(s):Rauchfuss, Thomas B.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:A diamagnetic salt of the (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb4\sp{2+}$ cluster cation was obtained by oxidation of (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb4$ with ((MeC$\sb5$H$\sb4)\sb2$Fe) PF$\sb6$. Variable temperature $\sp1$H NMR measurements showed that (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb4\sp{2+}$ is dynamic in solution; it exhibits signals for two chiral Ru sites at low temperatures but only one symmetrical Ru environment at high temperatures. Similar dynamic behavior was observed for (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$Se$\sb4$(PF$\sb6)\sb2$, while samples of (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$Te$\sb4$(PF$\sb6)\sb2$ showed only slight line broadening at low temperatures. The concentration independence of the coalescence temperature (T$\sb{\rm c}$) of the CH$\sb3$C$\sb5$H$\sb4$ signals showed that the exchange processes are intramolecular. The exchange barrier of (Me$\sb3$SiC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb4$(PF$\sb6)\sb2$ was found to be similar to those of (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$E$\sb4$(PF$\sb6)\sb2$ (E = S, Se), which indicates that the exchange processes do not involve hindered RCp rotation. The activation parameters were evaluated from analyses of the line shapes as a function of temperature; the free energies of activation range from 52 to 55 kJ/mol for all clusters.
((MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb3$(SCH$\sb3)$) CF$\sb3$SO$\sb3$ was obtained by the reaction of (MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb4$ with CH$\sb3$SO$\sb3$CF$\sb3$. Oxidation of ((MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb3$(SCH$\sb3$)) CF$\sb3$SO$\sb3$ with (Cp$\sb2$Fe) PF$\sb6$ yielded ((MeC$\sb5$H$\sb4)\sb4$Ru$\sb4$S$\sb3$(SCH$\sb3$)) (PF$\sb6)\sb2$CF$\sb3$SO$\sb3$. Both clusters exhibited dynamic behavior.
Salts of (C$\sb5$Me$\sb5)\sb3$Ru$\sb3$S$\sb4\sp+$ were obtained by reaction of (C$\sb5$Me$\sb5$)Ru(CH$\sb3$CN)$\sb3\sp+$ with (C$\sb5$Me$\sb5)\sb2$Ru$\sb2$S$\sb4$. The solid state structure of (C$\sb5$Me$\sb5)\sb3$Ru$\sb3$S$\sb4$(PF$\sb6$) showed that the cluster cation contains a new bonding mode for a persulfide ligand and defines a new structural motif for M$\sb3$S$\sb4$ clusters. Electrophiles react with (C$\sb5$Me$\sb5)\sb3$Ru$\sb3$S$\sb4\sp+$ and add to the bridging sulfur atoms. The core structure of the SO$\sb2$ adduct (C$\sb5$Me$\sb5)\sb3$Ru$\sb3$S$\sb3$(S$\sb2$O$\sb2)\sp+$ differs from that of (C$\sb5$Me$\sb5)\sb3$Ru$\sb3$S$\sb4\sp+$ in that it only has one persulfide ligand.
The reaction of tetramethyltetrathiafulvalene (TMTTF) with Fe$\sb4$S$\sb4$(NO)$\sb4$ gave the one-dimensional charge transfer salt (TMTTF)$\sb2$Fe$\sb4$S$\sb4$(NO)$\sb4$. Solid state measurements showed this material to be a paramagnetic semiconductor.
Issue Date:1994
Rights Information:Copyright 1994 Houser, Eric Jon
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9416373
OCLC Identifier:(UMI)AAI9416373

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