The synthesis and characterization of dimolybdenum and ditungsten fluoroalkoxides /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | In a series of dimolybdenum and ditungsten fluoroalkoxides of the form M2(OR)[t](NMe2)[m]L[n] are presented where R = C6F5, (CF3)2CH or (CF3)3C and L = NHMe2 or C5H5N. Mo2(NM23)6 reacts with six equivalents of pentafluorophenol in benzene to produce Mo2(OC6F5)4(NMe2)2(NHMe2)2. With ten equivalents, a number of products are isolated, including Mo2(OC6F5)5(NMe2) (NHMe2)2*2C6H6, [NH2Me2][Mo2(OC6F5)6(NHMe2)2] and Mo2(OC6F5)4(NHMe2)4. Extremely small amounts of moisture found in this hygroscopic alcohol also produce trace amounts of [(NH2Me2)2][Mo2O2(μ-O)2(OC6F5)4]. Mo2(CH2SiMe3)6 reacts with six equivalents of pentafluorophenol to yield Mo2(OC6F5)6 and tetramethylsilane quantitatively. The reaction of six equivalents of hexafluoroisopropanol with Mo2(NMe2)6 yields Mo2(OCH(CF3)2)4(NMe2)2(NHYMe2)2. With eight equivalents, Mo2(OCH(CF3)2)5(NMe2)(NHMe2)2 is produced, and in the presence of pyridine, Mo2(OCH(CF3)2)5(NMe2)2(py)2*C6H6 becomes the principal product. In addition, Mo2(OCH(CF3)2)4(py)4 has been isolated and structurally characterized. The reactions of perfluoro-tert-butanol have also been studied. Steric repulsion prevents the substitution of more than four alkoxides groups for amido groups; Mo2(OC(CF3)3)4(NMe2)2 has been crystallographically characterized, and has two unusual distinction. Firstly, it is the only known example of a trigonal fluoroalkoxide dimer. Secondly, this is the first trigonal transition metal dimer which exhibits a disorder of the metal centers within the averaged unit cell. Several reactions of W2(NMe2)6 with fluoroalcohols have been investigated. While hexafluoroisopropanol reactions typically produce intractable oily products, the reaction of W2(NMe2)6 with ten equivalents of pentafluorophenol yields W2(OC6F5)6(NHMe2)2 in good yield. If the reaction is repeated in the presence of pyridine, W2(OC6F5)4(HOC6F5)2(py)3*C6H6 is obtained... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | xv, 293 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 288-292). |