- 學位論文
新直線型九核鎳金屬串及不對稱型混價 七核鎳金屬串錯合物之合成與研究
Syntheses and Studies of the Novel Linear Nona-nickel and an Unusual Asymmetric, Mixed-Valence Hepta-nickel Metal String Complexes
摘要
本論文是利用配基微調的概念，設計兩種新型的九氮及七氮配基H3bnapya、H3phdptany，並將此兩種配基進一步合成對稱型九核鎳金屬串及不對稱型七核鎳金屬串錯合物作為研究主題。 首先利用九氮配基H3bnapya在高溫萘燒的反應條件下可得到全順向配位的九核鎳金屬串[Ni9(bnapya)4Cl2]4+，從磁性的分析可知，末端兩高自旋態的NiII (S = 1)之間為一弱反鐵磁性， J = －1.5 cm-1。藉由加入還原劑hydrazine，可得到還原兩個電子的錯合物2。並從結構上的鑑定得知此還原發生在萘啶內部的鎳金屬上，形成兩[Ni2]3+單元，彼此間為弱的反鐵磁性， J = －0.5 cm-1。隨著兩端萘啶單元間的距離拉長，其之間的作用力變小，符合在電化學及磁性上所得之結果。 在第二部份，利用七氮配基H3phdptany在高溫萘燒的反應條件，同樣可得到全順向配位的七核鎳金屬串[Ni7(phdptany)4Cl](PF6)(3)，經由單晶繞射鑑定，其分子為(4,0)-form的配位模式，即四個苯環官能基皆朝同一方向，且不具有軸向配基配位。經DFT理論計算及磁性、NIR光譜的分析，錯合物3為一NiI， NiII 及 NiIII混價的鎳金屬串，主要是由於不對稱配基兩端具有一定程度的差異性，造成金屬串的兩端分別穩定低氧化態及高氧化態的鎳金屬。另外，氧化一個電子的錯合物4之電子組態，藉由磁性及EPR光譜的量測來進一步佐證。 最後，利用H3bnapya、H3phdptany配基與不同的金屬起始物在甲醇溶劑下反應，可得到單核及雙核的金屬錯合物5~8。其中，九氮配基與不同的金屬反應，可得到不同的配位模式。
並列摘要
Two kinds of ligands with a terminal naphthyridyl group, a symmetrical bis(6-(1,8-naphthyridyl-α-amino)pyridyl)amine (H3bnapya) and an unsymmetrical 2-(phenyldipyridyltriamino)-1,8-naphthyridine (H3phdptany) which were prepared and characterized by 1H-NMR and ESI-MS. First, H3bnapya ligand were applied to synthesize linear nona-nickel metal string complexes [Ni9(bnapya)4Cl2](PF6)4 (1) and its two electrons reduced form [Ni9(bnapya)4Cl2](PF6)2 (2), both were structurally characterized. As far as the electronic structure is concerned, complex 1 exhibits [Ni9]18+ metal core. The complex exhibits a weak antiferromagnet- ic interaction (J = －1.51 cm-1) between the two terminal NiII ions, which have square-pyramidal coordination environment with high spin states. The magnetic coupling is significantly weak because the long distance of the two magnetic centers. Complex 1 undergoes a two-electrons reduction process leading to complex 2. Each dinickel unit attached to the naphthyridyl moieties is assumed to undergo a one-electron reduction, whereas the inner nickel ions formally remain NiII. Also, complex 2 shows an weak antiferromagnetic interaction between two (Ni2)3+ fragments, with J = －0.52 cm-1. Secondly, the unsymmetrical ligand H3phdptany were used synthesize linear hepta-nickel metal string complexes [Ni7(phdptany) 4Cl](PF6) (3), and its one-electron oxidation product [Ni7(phdptany)4Cl](PF6)2 (4). From the structural analysis, both complexes 3 and 4 are (4,0)-form because of the steric effect of the bulky phenyl groups. Magnetism, NIR spectroscopy and DFT calculations suggest that the metal framework of complex 3 should be described as a mixed-valence system of NiI, NiII and NiIII . The redox disproportionation was observed in the unsymmetrical ligand environment. The naphthyridyl site is in favor of [Ni2]3+ unit, and the amido site is in favor of NiIII .The one-electron oxidation of complex 3 occurs at naphthyridyl moiety, leading to the formation of complex 4, which are confirmed by magnetic measurement and EPR spectrum. Finally, the H3phdptany and H3bnapya ligands react with different metal precursors in MeOH leading to some mononuclear or dinuclear metal complexes 5~8. In the H3bnapya ligand system, different metals show different coordination modes.
參考文獻
延伸閱讀
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