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Title:Organometallic and Inorganic Derivatives of the Tetrathiometallates
Author(s):Howard, Kevin Edward
Doctoral Committee Chair(s):Rauchfuss, Thomas B.
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:In an effort to study the tetrathiometallates as ligands in heterometallic complexes, which may bind $\pi$-acidic coligands, the preparation of a number of low-valent organometallic derivatives of MoS$\sb4\sp{2-}$ and WS$\sb4\sp{2-}$ was undertaken. The complex ((COD)Rh) $\sb2$WS$\sb4$ 1 was prepared from the direct reaction of equimolar amounts of ((COD)RhCl) $\sb2$ and (Ph$\sb4$P)$\sb2$WS$\sb4$. Compound 1 was found to exhibit extensive ligand substitution chemistry, involving organophosphines, CO, and $t$-BuNC. It was found that 1 could only support two strongly $\pi$-acidic CO ligands; ((PPh$\sb3$)(CO)Rh) $\sb2$WS$\sb4$ was found to be the stable species. The reaction of Pd(WS$\sb4)\sb2\sp{2-}$ with an equimolar amount of ((COD)RhCl) $\sb2$ gave the insoluble species, (COD)Rh($\mu$-S)$\sb2$W($\mu$-S)$\sb2$Pd($\mu$-S)$\sb2$W($\mu$-S)$\sb2$Rh(COD). This complex reacted with excess PPh$\sb3$, giving the CH$\sb2$Cl$\sb2$-soluble species: (PPh$\sb3)\sb2$Rh($\mu$-S)$\sb2$W($\mu$-S)$\sb2$Pd($\mu$-S)$\sb2$W($\mu$-S)$\sb2$Rh(PPh$\sb3)\sb2$.
Complexes of general formula (($\eta\sp5$-C$\sb5$H$\sb4$R)Ru(PPh$\sb3$)) $\sb2$ME$\sb4$ (where R = H, CH$\sb3$; M = Mo, W; E = S, Se) were synthesized from two equivalents of ($\eta\sp5$-C$\sb5$H$\sb4$R)Ru(PPh$\sb3)\sb2$Cl and one equivalent of the corresponding (Ph$\sb4$P)$\sb2$ME$\sb4$. The WSe$\sb4$ derivative was prepared using ($t$-BuNH$\sb3)\sb2$WSe$\sb4$, which was obtained from the reaction of W(NH-$t$-Bu)$\sb2$(N-$t$-Bu)$\sb2$ with H$\sb2$Se. These compounds undergo single one electron oxidations in their cyclic voltammograms. Trialkylphosphines, carbon monoxide, and isocyanides (RNC, R = $t$-Bu, Me, and Bz) were found to displace the PPh$\sb3$ ligands in (CpRu(PPh$\sb3$)) $\sb2$WS$\sb4$ 2. In the case of CO however, substitution was observed to occur at only one ruthenium center. A kinetic study of the substitution of PPh$\sb3$ by $t$-BuNC in 2 revealed that the rate was independent of ($t$-BuNC), indicating a dissociative mechanism.
A number of (L$\sb{\rm n}$M$\sp\prime$) $\sb2$WS$\sb4$ complexes were prepared from WS$\sb4\sp{2-}$ and compounds of the type (L$\sb{\rm n}$M($\mu$-Cl)) $\sb2$. These included complexes where L$\sb{\rm n}$M was (NBD)Rh, (COD)Ir, ($\eta\sp5$-C$\sb5$Me$\sb5$)RhCl, and (allyl)Pd. The Rh(III) and Pd(II) derivatives were characterized by X-ray crystallography which showed M-W distances of 2.90A(av.) and 2.80A(av.) respectively. Poorly soluble complexes of the type (COD)PtMS$\sb4$ (M = Mo, W) were prepared from the reaction of (COD)PtCl$\sb2$ and (Ph$\sb4$P)$\sb2$MS$\sb4$. The thermal gravimetric analyses of ((COD)Rh) $\sb2$MS$\sb4$ and (COD)PtMS$\sb4$ over temperature ranges of 50-900$\sp\circ$C indicate the formation of MRh$\sb2$S$\sb{\rm x}$ (x = 2 or 2.5) and PtMS formulas. We suggest that these complexes should be examined as precursors to new ternary metal sulfides. (Abstract shortened with permission of author.)
Issue Date:1988
Description:158 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.
Other Identifier(s):(UMI)AAI8908710
Date Available in IDEALS:2014-12-15
Date Deposited:1988

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