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

167 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.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) (spacegroup 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 andother 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.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD