Metal-metal bond peripherals : synthesis and characterization of formamidinate complexes of iron, cobalt, niobium, and platinum /
The synthesis of several M-M bonded complexes using the
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739891261&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The synthesis of several M-M bonded complexes using the versatile amidinate ligand, (Ar)NC(R)N(Ar)-, R = H, Ph, Ar = Ph, Tol are presented. In the case of Pt, the compounds PtCl2(HDPhF)2, (la) and PtCl2(HDTolF)2, (lb), HDPhF = N, N'- diphenylformamidine, HDTolF = N, N'- di- p-tolylformamidine, have been prepared to give PT(II) starting materials which are soluble in most organic solvents. Deprotonation of the formamidine ligand in either la or lb produces the diplatinum compounds Pt2([]2-DArF)2([]-DArF)2, Ar = Ph(2a), and Tol(2b). Upon heating, they rearrange to give the tetrabridged compounds 3a and 3b respectively. Both 2a and 3a can be oxidized to give the mixed oxidation state PtII-PtIII compound, [Pt2(DTolF)4](PF6), 4. The PtIII-PtIII compound Pt2(DPhF)4Cl2, 5 has been synthesized from a melt reaction involving Pt2(OAc)4Cl2 and HDPhF. This compound completes a series of structurally homologous compounds in which the bond order varies from 0 to 1/2 to 1. For Fe and Co, the reaction Of MCl2(HDPhBZ)2, M = Fe(6) and Co(7), HDPhBz = N,N' - diphenylbenzamidine,. with a base in the presence of a reducing agent has produced the tris-bridged compounds M2(DPhBZ)3, M = Fe(8) and Co(9). For Fe, when methyllithium is used as the base in the absence of a reducing agent, the product Fe2([]2- DPhBZ)2([]-DPhBZ)2, 10 is formed. Decomposition in air of either the tris-bridged M2(DPhF)3 compounds or tetrabridged compounds M2(DPhF)4, leads to the formation Of M4O(DPhF)6, M = Fe(11) and Co(12) complexes. These compounds have a beryllium acetate type structure containing four metal atoms forming a pseudo tetrahedron around a central oxygen atom. For Nb, the NB(II) complex NbCl2(py)4, 13 was prepared for the first time and is used as a starting material. The reaction of the Nb(IV) starting material, NbCl4(THF)2 with LiDPhF forms the eight-coordinate complex Nb(DPhF)4, 14. Reaction of the metal-metal bonded complex Nb2Cl6(SMe2)3 with LiDPhF forms the complex, Nb2Cl3(Me2S)(DPhF)3, 15. Reduction of solutions containing the compounds Nb2Cl6(SMe2)3 and LiDPhF results in demethylation of dimethylsulfide giving Nb2(SMe)2(DPhF)4, 16 and methane gas. Several interesting features of these compounds will be discussed. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xiii, 170 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 162-167. |