University of Illinois Urbana-Champaign

The Effects of Main Group Elements on Transition Metal Carbonyl Clusters (Tellurium, Assembly, Chalcogen, Sulfur, Ditelluride)

Bogan, Leonard E., Jr.

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Description

Title
The Effects of Main Group Elements on Transition Metal Carbonyl Clusters (Tellurium, Assembly, Chalcogen, Sulfur, Ditelluride)
Author(s)
Bogan, Leonard E., Jr.
Issue Date
1986
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Inorganic
Abstract
  • The reaction of Fe(,3)Te(,2)(CO)(,9) with metal carbonyl dimers at 150-180(DEGREES) and under 1300-1750 psi of CO was found to be a convenient route for the synthesis of a variety of transition metal - tellurium car- bonyl clusters. One of these, Cp(,2)Mo(,2)FeTe(,2)(CO)(,7) (Cp = (eta)('5)-C(,5)H(,5)), 3, generates a reactive intermediate upon heating to 110(DEGREES). This inter- mediate was trapped with Fe(CO)(,5), CpCo(CO)(,2), and RCCH (R = Ph, H). Assembly schemes are proposed which rationalize the observed structures of these and other four, five, and six-vertex cluster sys- tems. One of these schemes involves cluster rearrangement by ver- tex dissociation, and such dissociation of Fe(CO)(,x) (x < 5) fragments was shown to occur at 0(DEGREES) in the reaction of Cp(,2)Mo(,2)(CO)(,4) with Fe(,2)(S(,2))(CO)(,6).
  • The crystal structures of 3 (space group P(')1), Cp(,2)Mo(,2)Co(,2)Te(,3)- (CO)(,4) (space group P(')1), Cp(,2)Mo(,2)Fe(,2)Te(,2)(CO)(,7) (space group Pn2(,1)a),
  • Cp(,2)Mo(,2)Fe(Te(,2)Br)(CO)(,5) (space group P(')1; a = 8.614(6), b = 14.641 (10), c = 7.181(7) (ANGSTROM); (alpha) = 91.92(7), (beta) = 111.69(6), (gamma) = 99.34(6)(DEGREES);
  • Z = 2; D(calcd) = 2.782 g/mL; 3216 reflections refined to R(,F) = 0.0576 and R(,wF) = 0.0598), Cp(,2)Mo(,2)Fe(Te(,2)SC(S)NEt(,2))(CO)(,5) (space
  • group P2(,1)/c), and Cp(,2)Mo(,2)FeTe(,2)(CO)(,3)(C(,2)H(,2)) (space group P2(,1)/n) were solved. Interactions between main group atoms in these and
  • other M(,3)E(,2) clusters are discussed in terms of cluster geometry and valence electron count.
  • Cyclic voltammetry of Fe(,3)Te(,2)(CO)(,9-n)L(,n) (L = PPh(,3), n = 0, 1; L = PMe(,2)Ph, n = 0-3) and CpCoFeTe(,2)(CO)(,6) is reported and discussed in terms of ligand effects and charge delocalization in the clusters.
  • Oxidation of 3 with Br(,2)/CO gave a good yield of CpMoFe- (Te(,2)Br)(CO)(,5), which features a novel Te(,2)Br ligand. In solution the compound undergoes rapid exchange of Br making the Te atoms equivalent, but at -88(DEGREES) in toluene this exchange is slowed enough that ('1)H NMR indicates a chiral compound.
  • Reaction of (RC(,5)H(,4))MoFe(Te(,2)Br)(CO)(,5) (R = Me, i-Pr) with AgSb- F(,6) generated (RC(,5)H(,4))MoFe(Te(,2))(CO)(,5) SbF(,6). The cation reacted with a variety of nucleophiles (Br('-), Et(,2)NCS(,2)('-), HCOO('-), H('-), PMe(,2)Ph) to give compounds which apparently result from attack at Te.
Graduation Semester
1986
Type of Resource
text
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http://hdl.handle.net/2142/70338

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