Reactions of thiols with low valent transition metals : from metal(0) thiol complexes to metal(II) thiolatohydrides /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Synthetic methodology has been developed for preparation of the thiol complexes, cis-(RSH)Cr(CO)4L, = CO; R = Bu^t, Ph, L = PEt3). X-ray diffraction analysis was conducted for Bu^tSH)Cr(CO)5. Reactivity studies revealed the coordinated thiols to be more acidic than the free thiols. The primary decomposition route was chromium-sulfur bond cleavage without evidence for S-H oxidative addition even under photolytic conditions. The heavy metal congener derivative, (PhSH)W(CO)5, yielded S-H oxidative addition products when photolyzed. The preferred site for protonation, iron or sulfur, of the derivatives, trans-RSFe(CO)3L- was examined by Fenske-Hall molecular orbital calculations. The Mulliken atomic charge on both the iron and chalcogen was dependent on both the R and L substituents. The charge on sulfur was determined to be greater than the charge on iron in all cases examined except trans-PhSFe(CO)3PH3-. These results corroborated the low temperature protonation experiments previously performed in our laboratories. The success of the oxidative addition of acids, HX, to [Ni(PCy3)2]2N2 yielding trans-HNi(X)(PCy3)2 correlated with the aqueous acidity values of the acids with the more acidic substrates yielding products. Protonolysis reactions of trans-HNi(X)(PCy3)2 with HY resulted in exchange of Y for X at nickel depending upon X and Y. No reactivity at Ni-H was observed. Quantitative measurements of the equilibrium for one of the protonation reactions determined the nickel-formate ligand strength in trans-HNi(O2CH)(PCy3)2 was ca. 30 kcal-mol^-1 stronger than the nickel-phenylthiolate bond in trans-HNi(SPh)(PCy3)2. Sulfur-carbon bond cleavage and methane evolution resulted upon addition of MeS(CH2)3SH to [Ni(PCy3)2]2N2. Methane was also produced via sulfur-carbon bond cleavage upon addition of hydride to trans-HNi(SMe)PCy3)2. The mechanism of the H/D exchange in trans-DNi(O2CH)(PCy3)2 was found to be first-order in metal complex... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | xvii, 161 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |