Synthesis, structure, spectroscopy, magnetism and theoretical investigation of bi- and trimetallic complexes.
Date Issued
2008
Date
2008
Author(s)
Wang, Hui-Ting
Abstract
The aim of this thesis is to investigate the synthesis, structure, spectroscopy, magnetism and theretical investigation of the dimeric copper(II) complexes and the heterotrinuclear metal string complexes. The two bis-methoxyl-bridged dicopper(II) complexes, [Cu2(μ-OMe)2(L1)(2-aminopyridine)2](ClO4)2 (1) (L1 = N,N''-bis(2-pyridinyl)methanediamine) and [Cu2(μ-OMe)2(2-amino-pyrimidine)4](ClO4)2 (2), have been isolated and characterized by X-ray crystallography. The coordinated geometries of Cu(II) ions of complex 1 are distorted square pyramidal, and those of complex 2 are square planar. Magnetic measurements for both complexes in the 4–300 K range indicate a strong antiferromagnetic interaction (J = -834 cm-1) for complex 1 and a relative weak one (J = -41 cm-1) for complex 2. The difference of the antiferromagnetic interaction between complex 1 and 2 could be explained by the variations of their structure. On the other hand, the two Cu(II) ions of the complex 3,[Cu2(μ-O2CCH3)4(2-aminopyridine)2], are square pyramidal coordinated and connected with four acetate-bridged lignads. Magnetic measurement for the complex 3 shows an antiferromagnetic interaction (J = -329 cm-1) which occurs directly through the space. The second part of studies is focus on the exchange interaction of linear heterotrinuclear complexes. By replacing the axial ligands of [CuPdCu(dpa)4(Cl)2] (4) and [CoPdCo(dpa)4(Cl)2] (7), [CuPdCu(dpa)4(MeCN)2](ClO4)2(6) and [CoPdCo(dpa)4(MeCN)2](ClO4)2 (8) have been designed and synthesized. They are structurally similar to their parental complexes 4 and 7. The X-ray structure studies reveal the terminal Cu(II) or Co(II) ions of complexes 6 and 8 are five-coordinate and the inner palladium ion with four-coordinate. The magnetic measurement for complex 6 shows a weak antiferromagnetic interaction (J = -17 cm-1). owever, the exchange interaction of 8 indicates a strong antiferromagnetic behavior (J = -300 cm-1). The explanation of this difference may be ascribed to the diversity of exchange pathways.
Subjects
magnetism
structure
Type
thesis
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