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Title:Synthesis and Reactivity of Dichalcogenide and Substituted Dichalcogenide Ligands in Molecular and Nonmolecular Compounds
Author(s):Hoots, John Edward
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:An array of mono- and 1,2-disubstituted derivatives of the (eta)('2)-S(,2) and Se(,2) ligand systems have been prepared. The reactivity and distinctive ('1)H NMR spectroscopic behavior of complexes containing these ligands have been examined. The reactivity studies were extended to solid-state metal sulfides, particularly pyrite (FeS(,2)).
{Ir(S(,2)CH(,3))(dppe)(,2)}('2+) (dppe = Ph(,2)PCH(,2)CH(,2)PPh(,2)) is a potent chalcogen-transfer reagent towards nucleophiles (Ph(,3)P, CH(,3)NC, CN('-)) and several reaction pathways have been observed. The multistep reaction with 2 CH(,3)NC produced cis-{Ir(CH(,3)NC)(SCH(,3))(dppe)(,2)}('2+) and serves as a model for the Oxirane olefin epoxidation process. Organoperacids effect facile oxidation of {Ir(E(,2))(dppe)(,2)}('+) (E = S, Se) complexes to the (eta)('2)-S(,2)O, S(,2)O(,2), and Se(,2)O derivatives. Likewise, oxidation of (C(,5)H(,5))Nb(S(,2))Cl produced an (eta)('2)-S(,2)O ligand. The reaction of {Ir(S(,2)O(,x))(dppe)(,2)}('+) (x = 1,2) with CH(,3)OSO(,2)F formed the corresponding O-alkylated (eta)('2)-S(,2)O(,x)CH(,3) derivatives.
Attempted synthesis of the first (eta)('1) or (eta)('2)-SO ligand by sulfur-abstraction from complexes containing (eta)('2)-S(,2)O ligands was unsuccessful, but formation of {Ir(SeS)(dppe)(,2)}('+) was observed in the reaction of Ir(dppe)(,2)('+) and (CH(,3)C(,5)H(,4))(,2)Ti S(,x)Se(,5-x). A stabilized form of the SO unit, the O-methyl thioperoxide ligand, was observed in Ir((eta)('1)-SOCH(,3))(CH(,3)NC)(dppe)(,2)('2+) and produced by abstraction of the unsubstituted sulfur in {Ir(S(,2)OCH(,3))(dppe)(,2)}('2+) with CH(,3)NC.
Formation of pollutants, such as SO(,2), from the decomposition of pyrite has remained a major barrier to the increased use of coal as a fuel source. Desulfurization of pyrite with (n-C(,4)H(,9))(,3)P at 260(DEGREES)C produced an equilibrium mixture of FeS and Fe(,0.95)S and the corresponding phosphine sulfide: Partial desulfurization of an array of metal sulfides (MoS(,3), CoS(,2), Cu(,2)S) with organophosphines demonstrated this reaction's generality.
Catalytic desulfurization of pyrite with R(,3)P reagents was accomplished by addition of iron as a sulfur-receptor. An overall rate of (TURN)40 turnovers/hr and 85% conversion to Fe(,0.99)S was observed with an 100:1 ratio of FeS(,2) to (n-C(,4)H(,9))(,3)P at 300(DEGREES)C.
The stoichiometric organophosphine desulfurization reaction was applied to a dried sample of Illinois coal (2.0% FeS(,2)). Complete conversion of pyrite to pyrrhotite and 90% recovery of free organophosphine sulfide was accomplished.
Issue Date:1984
Description:193 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
Other Identifier(s):(UMI)AAI8409781
Date Available in IDEALS:2014-12-15
Date Deposited:1984

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