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Title:Chemistry of Ruthenium and Rhodium Eta(4)-Thiophene Complexes
Author(s):Luo, Shifang
Doctoral Committee Chair(s):Rauchfuss, Thomas B.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:Reduction of ($(\eta\sp6$-$\rm C\sb6Me\sb6)Ru(\eta\sp5$-C$\sb4$R$\sb4$S)) (OTf)$\sb2$(C$\sb4$R$\sb4$S = C$\sb4$H$\sb4$S (1a), 2,5-Me$\sb2$C$\sb4$H$\sb2$S (1b), and 2,3,4,5-Me$\sb4$C$\sb4$S (1c)) and (($\eta\sp5$-C$\sb4$Me$\sb4$S)$\sb2$Ru) (OTf)$\sb2$ (1d) with Cp$\sb2$Co produces (arene)Ru($\eta\sp4$-C$\sb4$R$\sb4$S) (2a-d). 2d is unstable $>-20\sp\circ$C. It reacts with Fe(CO)$\sb5$ in the presence of Me$\sb3$NO to yield the thermally stable $(\eta\sp5$-$\rm C\sb4Me\sb4S)Ru(\eta\sp4{:}\eta\sp1$-$\rm C\sb4Me\sb4S)Fe(CO)\sb4$(2d$\cdot$Fe(CO)$\sb4).$
Thermolysis of (C$\sb5$Me$\sb5$)Rh($\eta\sp4$-C$\sb4$Me$\sb4$S) (2e) gives $(\rm C\sb5Me\sb5)\sb3Rh\sb3 (\eta\sp4{:}\eta\sp1$-C$\sb4$Me$\sb4$S)$\sb2$ (3) and C$\sb4$Me$\sb4$S. 3 further decomposes to give (C$\sb5$Me$\sb5)\sb2$Rh$\sb2$(C$\sb4$Me$\sb4$S) (4). Thermolysis of 2c in non-aromatic solvents such as hexane produces (C$\sb6$Me$\sb6)\sb3$Ru$\sb3$ $(\eta\sp4{:}\eta\sp1$-C$\sb4$Me$\sb4$S)$\sb2$ (5a). In aromatic solvents, thermolysis of 2c yields the arene exchange products $(\eta\sp6$-solvent)(C$\sb6$Me$\sb6) \sb2$Ru$\sb3(\eta\sp4{:}\eta\sp1$-C$\sb4$Me$\sb4$S)$\sb2$ (solvent = C$\sb6$D$\sb6$ (5b), toluene (5c)) at low concentrations while at high concentrations it yields both 5a and 5b (in C$\sb6$D$\sb6$) or 5c (in toluene). In the presence of H$\sb2$, 2c decomposes to give (C$\sb6$Me$\sb6)\sb2$Ru$\sb2$ $(\eta\sp4{:}\eta\sp1$-C$\sb4$Me$\sb4$S)(H)$\sb2$ (6).
Protonation of 2a-c with NH$\sb4$PF$\sb6$ affords (($\eta\sp6$-$\rm C\sb6Me\sb6)Ru(\eta\sp4$-2-H-C$\sb4$R$\sb4$S)) PF$\sb6$ (7a-c). The added proton is in the endo position of the carbon $\alpha$ to sulfur. Protonation of 2d with NH$\sb4$PF$\sb6$ also affords the analogous ($(\eta\sp5$-C$\sb5$Me$\sb5$)Rh($\eta\sp4$-$2$ -H-C$\sb4$Me$\sb4$S)) PF$\sb6$ (7d). Complex 7a undergoes C-S bond cleavage both in solution and the solid state to afford the thiapentadienyl complex (($\eta\sp6$-$\rm C\sb6Me\sb6)Ru(\eta\sp5$-CH$\sb2$=CH-CH=CH-S)) PF$\sb6$ (8).
Complex 2e reacts with Fe$\sb3$(CO)$\sb $ to give (C$\sb5$Me$\sb5$)Rh$\{\eta\sp5$-C$\sb4$Me$\sb4$Fe(CO)$\sb3\}$ (9) and (C$\sb5$Me$\sb5$)Rh($\eta\sp4$:$\eta\sp1$-C$\sb4$Me$\sb4$S)Fe(CO)$\sb4$ (10). 10 has been prepared in high yields from the reaction of 2e with Fe(CO)$\sb5$ in the presence of Me$\sb3$NO. Thermolysis of 10 gave 9, C$\sb4$Me$\sb4$S, and (C$\sb5$Me$\sb5)\sb2$Rh$\sb2(\mu$-CO)($\mu\sb3$-S)Fe(CO)$\sb3$ (11) in ca. 2:2:1 molar ratio. A double labeling thermolysis experiment shows that the Rh-C$\sb4$Me$\sb4$S fragment in 10 remains intact during its desulfurization.
Issue Date:1993
Description:182 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993.
Other Identifier(s):(UMI)AAI9329104
Date Available in IDEALS:2014-12-17
Date Deposited:1993

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