Structural studies of transition metal complexes of electron-rich cis-dithiolate ligands /
The reactivity of electron-rich cis-dithiolate ligands in metallocomplexes has been extensively studied using the compound [N,N'-bis-(mercaptoethyl)-1,5-diazocyclooctanato]Ni¹¹, (bme-daco)Ni. The sulfur sites in (bme-daco)Ni readily react with electrophiles, both organic and inorganic, produci...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2003.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765867401&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The reactivity of electron-rich cis-dithiolate ligands in metallocomplexes has been extensively studied using the compound [N,N'-bis-(mercaptoethyl)-1,5-diazocyclooctanato]Ni¹¹, (bme-daco)Ni. The sulfur sites in (bme-daco)Ni readily react with electrophiles, both organic and inorganic, producing thioether ligands and polymetallic aggregates among others. This same reactivity is seen with the complex (u-S)₂Fe₂(CO)₆²⁻ which readily reacts with haloalkanes producing dithiolate species and with divalent metals producing polymetallic species. The dithiolate diiron hexacarbonyl complexes resulting from reactions of (u-S)₂Fe₂(CO)₆²⁻ with haloalkanes can be used as entry to compounds which are structural models of the active site of [Fe]H₂ase. A series of (u-SRS)[Fe(CO)₂L]₂ complexes with R = (CH₂)₂, (CH₂)₃ and o-CH₂C₆H₄CH₂ and L = PMe₃ or PMe₂Ph has been structurally characterized and are compared to the (u-RS)₂[Fe(CO)₂L]₂ analogue as well as to the diiron organometallic active site structure. The complex [N,N'-bis-(2-mercapto-2-methylpropyl)-1,5-diazocycloocta-nato]Ni¹¹ (bme*daco)Ni, a derivative of (bme-daco)Ni, has steric hindrance at S, lessening the tendency to form polymetallic aggregates. However, upon reaction of CuCl with (bme*daco)Ni a mixed-valent, mixed-metal hexametallic species is obtained. In a similar reaction utilizing the complex (bme*daco)Cu, a mixed-valent hexacopper aggregate is obtained. The molecular structures of the hexanuclear compounds as determined by x-ray crystallography demonstrate an adamantine-like topology has been templated by the (bme*daco)M units. Further characterization by mass spectrometry, Vis/UV, electrochemistry, and electron paramagnetic resonance spectroscopy is presented. The complex [N,N'-bis(mercaptoethyl)-1,4-diazocycloheptanato]NiII, (bme-dach)Ni, contains a seven member diazocycle backbone. The reduced ring size changes electronic character of the N₂S₂ cavity about the coordinated nickel ion. This change is more readily observed structurally when the sulfur atoms are derivatized either by alkylation or metalation. A structural comparison of the trinickel aggregates utilizing (bme-daco)Ni and (bme-dach)Ni is also presented. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xix, 253 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 129-136). |