CATALYTIC OXIDATION OF SULFUR COMPOUNDS. SYNTHETIC, STRUCTURAL, AND THEORETICAL STUDIES OF MOLYBDENUM AND TUNGSTEN COMPLEXES.

Persistent Link:
http://hdl.handle.net/10150/187631
Title:
CATALYTIC OXIDATION OF SULFUR COMPOUNDS. SYNTHETIC, STRUCTURAL, AND THEORETICAL STUDIES OF MOLYBDENUM AND TUNGSTEN COMPLEXES.
Author:
CHANDLER, TRAVIS.
Issue Date:
1983
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The electronic structures and bonding interactions in the syn and anti isomers of Mo₂S₄(edt)₂²⁻ (edt = ethanedithiolato, (SCH₂CH₂S)²⁻) were examined and compared through Fenske-Hall and extended Huckel molecular orbital calculations. The electronic structures of a hypothetical closed isomer and the fragment MoS₃(edt)³⁻ were calculated as well. A molybdenum-molybdenum bonding interaction accounts for the diamagnetism of the complexes and is important in determining the relative stabilities of the isomers (syn > closed > anti). The structure of the syn isomer of (P(C₆H₅)₄)₂W₂S₄(edt)₂ was determined by X-ray crystallography. The compound crystallizes in the space group P2₁/n with a = 16.126(7)A, b = 25.03(1)A, c = 13.021(6)A, β = 101.73(4)°, and Z = 4. The calculated and observed densities are 1.755 and 1.757 g cm⁻³. Full-matrix least squares refinement of the 7414 data with Fₒ² > 3σ(Fₒ²) gave R = 0.039 and R(w) = 0.046. Each tungsten atom is ligated by five sulfur atoms in approximate tetragonal-pyramidal geometry. The W-W distance is 2.862(1)A, indicating a metal-metal bond. The average W-S(terminal) distance is 2.144(2)A, the average W-S(bridging) is 2.328(2)A, and the average W-S(edt) distance is 2.404(2)A. A variety of sulfur compounds, including hydrogen sulfide, aromatic and aliphatic thiols, cysteine, and bisulfite reduced MoO(TTP)OR, oxoalkoxotetratolylporphinatomolybdenum(V) (R = H, CH₃, C₂H₅, C₅H₁₁, MoO(TTP)), to the corresponding Mo(IV) species, MoO(TTP). The kinetics of the redox reaction between MoO(TTP)OC₂H₅ and RSH (R = C₂H₅, C₆H₅) were monitored at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))(RSH), with k₂ = 8.0 x 10⁻¹³ M⁻¹sec⁻¹ for C₂H₅SH and k₂ = 8.2 M⁻¹sec⁻¹ for C₆H₅SH describes the kinetic data. Sulfur compounds also reduced MoO₂(TTP). The kinetics of the redox reaction of the novel compound MoO(TTP)HSO₃ were monitored in chloroform solution at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))² with k₂ = 3.4 x 10² M⁻¹sec⁻¹ describes the kinetic data. Oxidation of MoO(TTP) to Mo(V) occurs in the presence of air. Oxidation catalysis by oxomolybdenum porphyrins was demonstrated for the substrates C₂H₅SH, C₆H₅SH, and HSO₃⁻. Mechanisms for these reactions are proposed.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Enzymes.; Organomolybdenum compounds.; Organosulfur compounds.; Organotungsten compounds.; Molybdenum.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCATALYTIC OXIDATION OF SULFUR COMPOUNDS. SYNTHETIC, STRUCTURAL, AND THEORETICAL STUDIES OF MOLYBDENUM AND TUNGSTEN COMPLEXES.en_US
dc.creatorCHANDLER, TRAVIS.en_US
dc.contributor.authorCHANDLER, TRAVIS.en_US
dc.date.issued1983en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe electronic structures and bonding interactions in the syn and anti isomers of Mo₂S₄(edt)₂²⁻ (edt = ethanedithiolato, (SCH₂CH₂S)²⁻) were examined and compared through Fenske-Hall and extended Huckel molecular orbital calculations. The electronic structures of a hypothetical closed isomer and the fragment MoS₃(edt)³⁻ were calculated as well. A molybdenum-molybdenum bonding interaction accounts for the diamagnetism of the complexes and is important in determining the relative stabilities of the isomers (syn > closed > anti). The structure of the syn isomer of (P(C₆H₅)₄)₂W₂S₄(edt)₂ was determined by X-ray crystallography. The compound crystallizes in the space group P2₁/n with a = 16.126(7)A, b = 25.03(1)A, c = 13.021(6)A, β = 101.73(4)°, and Z = 4. The calculated and observed densities are 1.755 and 1.757 g cm⁻³. Full-matrix least squares refinement of the 7414 data with Fₒ² > 3σ(Fₒ²) gave R = 0.039 and R(w) = 0.046. Each tungsten atom is ligated by five sulfur atoms in approximate tetragonal-pyramidal geometry. The W-W distance is 2.862(1)A, indicating a metal-metal bond. The average W-S(terminal) distance is 2.144(2)A, the average W-S(bridging) is 2.328(2)A, and the average W-S(edt) distance is 2.404(2)A. A variety of sulfur compounds, including hydrogen sulfide, aromatic and aliphatic thiols, cysteine, and bisulfite reduced MoO(TTP)OR, oxoalkoxotetratolylporphinatomolybdenum(V) (R = H, CH₃, C₂H₅, C₅H₁₁, MoO(TTP)), to the corresponding Mo(IV) species, MoO(TTP). The kinetics of the redox reaction between MoO(TTP)OC₂H₅ and RSH (R = C₂H₅, C₆H₅) were monitored at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))(RSH), with k₂ = 8.0 x 10⁻¹³ M⁻¹sec⁻¹ for C₂H₅SH and k₂ = 8.2 M⁻¹sec⁻¹ for C₆H₅SH describes the kinetic data. Sulfur compounds also reduced MoO₂(TTP). The kinetics of the redox reaction of the novel compound MoO(TTP)HSO₃ were monitored in chloroform solution at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))² with k₂ = 3.4 x 10² M⁻¹sec⁻¹ describes the kinetic data. Oxidation of MoO(TTP) to Mo(V) occurs in the presence of air. Oxidation catalysis by oxomolybdenum porphyrins was demonstrated for the substrates C₂H₅SH, C₆H₅SH, and HSO₃⁻. Mechanisms for these reactions are proposed.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectEnzymes.en_US
dc.subjectOrganomolybdenum compounds.en_US
dc.subjectOrganosulfur compounds.en_US
dc.subjectOrganotungsten compounds.en_US
dc.subjectMolybdenum.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.committeememberRunden_US
dc.contributor.committeememberFernandoen_US
dc.contributor.committeememberGlassen_US
dc.contributor.committeememberKelleren_US
dc.identifier.proquest8410807en_US
dc.identifier.oclc690683134en_US
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