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Title:Synthesis and Characterization of Derivatives of Triironnonacarbonyl Ditelluride and Related Compounds
Author(s):Lesch, David Allen
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:Fe(,3)Te(,2)(CO)(,9) can be prepared from Fe(CO)(,5)/OH('-) and TeO(,3)('2-) in90% yield. In polar solvents Fe(,3)Te(,2)(CO)(,9) reacts with Lewis bases(PR(,3), P(OR)(,3), NH(,3) CO, RNC, I('-), OH('-)) to form stable adducts at theexpense of an Fe-Fe bond. An X-ray crystal structure of the adductFe(,3)Te(,2)(CO)(,9)PPh(,3) reveals a pentagonal bipyramid with two oppositeequatorial vertices unoccupied. These adducts lose CO upon
heating to give substituted clusters Fe(,3)Te(,2)(CO)(,9-x)L(,x). This reversibleopening of an Fe-Fe bond allows substitution of up to six carbonylswith the small ligand p(OCH(,2))(,3)CCH(,3). Both the extent and dispositionof ligand substitution is governed by the size of the ligand, asdetermined by ('31)P NMR spectroscopy. An X-ray crystal structureof Fe(,3)Te(,2)(CO)(,7)(PPh(,3))(,2) shows a PPh(,3) ligand attached to each ofthe sterically less encumbered six-coordinate irons. The two Fe-Fe
bonds of the square pyramid are unusually long (2.74 (ANGSTROM)) and can be^related to its reactivity. Reaction of Fe(,3)Te(,2)(CO)(,9) with CpM(CO)(,2)^(M = Co, Rh, Ir) and Pt(PPh(,3))(,2)C(,2)H(,4) yields (CO)(,6)Fe(,2)Te(,2)MCp(CO)^and (CO)(,6)Fe(,2)Te(,2)Pt(PPh(,3))(,2), respectively. Via spectroscopic^comparison these four compounds are shown to have structures^analogous to Fe(,3)Te(,2)(CO)(,9)PPh(,3) and (CO)(,6)Fe(,2)Se(,2)Pt(PPh(,3))(,2).^(CO)(,6)Fe(,2)Se(,2)Pt(PPh(,3))(,2), which was prepared from Fe(,2)Se(,2)(CO)(,6)^and Pt(PPh(,3))(,2)C(,2)H4, was characterized crystallographically.
(CO)(,6)Fe(,2)Te(,2)MCp(CO) (M = Co, Rh) undergo reversibledecarbonylation to give compounds analogous to Fe(,3)Te(,2)(CO)(,9).Narrow chemical shift regions differing by over 2000 ppm areobserved in the ('125)Te NMR spectra of these clusters dependingon whether one or two metal-metal bonds are present. Fe(,2)E(,2)(CO)(,6)(E = S, Se, Te) are useful precursors to mixed-metal clusters andcan undergo thermal or photochemical dimerization.
Issue Date:1983
Description:138 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
Other Identifier(s):(UMI)AAI8309975
Date Available in IDEALS:2014-12-15
Date Deposited:1983

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