Syntheses and reactions of nickel complexes with P, S donor atoms /
The synthesis of new ligands such as arom-PSSP, PS-et-SP, PS-xy-SP, as well as known ligands arom-PSR ( R = Me, Et), arom-PSEt, PSSP and PSET has been studied for the purpose of developing systematic preparative methods for organometallic complexes of nickel(II) as well as low valent nickel(I) and n...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743267131&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The synthesis of new ligands such as arom-PSSP, PS-et-SP, PS-xy-SP, as well as known ligands arom-PSR ( R = Me, Et), arom-PSEt, PSSP and PSET has been studied for the purpose of developing systematic preparative methods for organometallic complexes of nickel(II) as well as low valent nickel(I) and nickel(I) complexes. All of these P, S donor atom ligands were fully characterized by 31P and 1H NMR spectra. Upon the addition of each ligand to a 2-propanol solution of Ni(BF4)2-6H20 provided corresponding air-stable, yellow solids of [(p2S2)Nil(BF4)2 (p2S2 = bi- or tetradentate P, S donor atom ligands) which were characterized by X-ray crystallography and elemental analyses. Cyclic voltammograms of [(P2s2)Nil(BF-4)2 complexes in CH3CN showed two reversible redox events assigned to Nill/I and Nil/0. The one-electron reduction of [(P2s2)Nil(BF4)2 complexes produced nickel(I) species which exhibited a EPR signal with hyperfine coupling to two phosphorus atoms. Complete bulk chemical reduction of f(P2s2)Nil(BF4)2 complexes with sodium mercury amalgam or ligand displacement reactions of Ni(COD)2 permitted the isolation of red solids or red solutions of (P2S2)NiO complexes. Oxidative addition reactions of HBF4 to (p2S2)NiO complexes yielded nickel(II) hydride complexes of f(H)(P2s2)Ni]BF4. Deprotonation of these hydride complexes by a base produced original (P2s2)NiO complexes. Treatment of both (P2S2)NiO and [(H)(P2S2)Ni]BF4 complexes with CO provided di- and tricarbonyl nickel(O) complexes. The phosphine/CO exchange around tetrahedral nickel(O) metal center showed a strong dependence on the cone angle of the phosphine's substituents. Mechanistic studies of the reductive reaction of nickel hydride complexes with CO suggested that strong acidic species is generated as an intermediate during the reaction. Photolysis of (P2s2)NiO complexes led to S-dealkylation to produce dithiolate nickel(II) complexes of (Ph2p(o-c6H4)S)2Nill ((arom-PS)2Nill) and Ph2PCH2CH2S)2Nill ((PS)2Nill). The former was characterized by X-ray crystallography. Mechanistic studies of the light induced S-dealkylation of (p2s2)NiO complexes displayed the formation of alkyl radicals and nickel(l) species as intermediates during the reaction. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xxi, 185 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |