Syntheses and Studies of the Extended Metal Atom Chains: Deca-nickel String Complex and a Series of Nona-nickel String Complexes
Date Issued
2011
Date
2011
Author(s)
Kuo, Jau-Huei
Abstract
A decanickel extended metal atom chains (EMACs) complex with a new pyridyl- and naphthyridyl-modulated ligand (H4bdpdany) was successfully synthesized. The crystal structure of the complex [Ni10(N10)4(NCS)2](PF6)2 shows that all of the N104- ligands bind the metal in an all-syn conformation and X-ray structural studies reveal that the short Ni-Ni distances in the range of 2.36~2.23 Å. The temperature dependent magnetic measurements performed on two independent high spin nickel(II) ions of complex [Ni10(μ10-N10)4(NCS)2](PF6)2 demonstrate that the metal chain is antiferromagnetic. The longer distance between the two terminal high spin nickel(II) ions compared with tetranickel-strings and hexanickel-strings causes the decrease in antiferromagnetic interaction.
Second research of nona-nickel string complexes is devoted to investigate the effect of drawing or donating modified ligand. So our group try to synthesize several kinds of bis(2-pyridyl-1,8-naphthyridine-7-yl)amine ligand with modified pyridyl group. Then through our experimental process we could get four plus nona-nickel string complexes with electron-donating modified ligand and two plus nona-nickel string complexes with electron-drawing mortified ligand. According the cycling voltammograms, nona-nickel string complexes with electron-donating modified ligand exhibit three redox couples and one oxide wave and electron-donating modified ligand exhibit four redox couples and two oxide wave. Hence, it’s possible to get the several valences nona-nickel complexes from reacting with the corresponding different oxidant or reductant.
X-ray structure studies reveal that the Ni-Ni bond distances have some significant differences (ca. 0.03 Å) between two plus complex and four plus complex.
These results reveal that the 1,8-naphthridinyl group could stabilize Ni23+ mixed-valent unit.
Subjects
Metal string
Metal-metal bond
Magnetic
Type
thesis
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