Synthetic, Structural, and Magnetic Studies of Trinickel String Complexes Supported by Thione-naphthyridine Ligands

• Main Authors: Chien-Hung Cheng, 鄭健鴻
• Other Authors: 彭旭明
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/8467bj

碩士 === 國立臺灣大學 === 化學研究所 === 106 === Recently, it has been shown that the introduction of a planar NNO based ligand scaffold in metal string complexes plays a pivot role in boosting the single molecule conductance. Inspired by this study, herein we report the preliminary investigation on the novel trinickel string complexes [Ni3(npt)4(Cl)] (1) and [Ni3(npt)4(NCS)] (3) supported by NNS type ligand. The cyclic voltammetry of complex 3 exhibits only one-electron redox processes at E1/2 = 0.301 V. The one-electron oxidation species [Ni3(npt)4(Cl)](PF6) (2) and [Ni3(npt)4(NCS)](PF6) (4) can be synthesized by reacting 1 and 3 with one equivalent of [FeCp2](PF6) in CH2Cl2. The further reaction of 4 with NaNCS afford [Ni3(npt)4(NCS)2] (5). Base on X-ray studies and magnetic susceptibility measurements, 3 has a mixed-valent, high spin (S = 3/2) [Ni2]3+ unit within the metal framework. The magnetic measurements show that 3 is likely paramagnetic compound, and μeff = 3.78 B.M. at 300 K. The metal framework of 4 has a [Ni3]6+ core, is likely paramagnetic compound and μeff = 2.91 B.M., we assign that the terminal nickel ion which coordinate to the thiocyanate is high spin state (S = 1). Complex 5 likely antiferromagnetically coupled (J = -171.15 cm-1) with two terminal high spin Ni2+ (S = 1) ions and one diamagnetic low spin Ni2+ ion in the central position.