立障萘啶酮配位基之三核金屬串合成與研究

Synthesis and Studies of Triunclear Metal String Complexes with Bulky Ligand (7-methyl-1,8-naphthyridin-2(1H)-one)

郭世英(Shih-Ying Kuo)

指導教授 ： 彭旭明

國立臺灣大學/理學院/化學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201902440

摘要

本篇論文使用帶有甲基的立障不對稱型萘啶酮(7-methyl-1,8-naphthyridin-2(1H)-one, Hmnpo)配基來合成出第二周期過渡金屬非螺旋性金屬串錯合物，並透過X-ray單晶繞射、循環伏安法、紫外光-可見光光譜、核磁共振儀來鑑定及探討其性質。在合成上，將立障萘啶酮配基分別加入釕(ruthenium)以及鉬(molybdenum)的相關前驅物並以萘(naphthalene)作為溶劑，於攝氏220度含氬氣的條件下進行萘燒反應8個小時，透過分層養晶(bilayer)的方式可得到第二周期過渡金屬的三核金屬串錯合物Ru3(mnpo)4Cl(PF6) (1)以及RuMoRu(mnpo)4Cl(PF6) (2)。錯合物(2)是第一個RuMoRu的三核金屬串錯合物被合成出來。透過單晶繞射的結構可以發現，四片配位基皆有脫氫的情形，並以非螺旋的形式和金屬串配位。因為配基的立障因素，其中一片配基有移位的現象發生，造成萘啶上的一個氮原子沒有和金屬配位，此金屬串並沒有失序(disorder)的情形，因此有利於結構的探討。由第二周期過渡金屬三核金屬串的分子軌域可以判斷，錯合物(1)和(2)的相近金屬離子之間的鍵級均為1.5鍵，在磁性上均為逆磁。從單晶結構可以發現，錯合物(1)及錯合物(2)的相鄰金屬離子鍵長均在2.25Å ~ 2.27Å之間，屬於1.5鍵的範圍。錯合物(2)的核磁共振圖譜以及順磁共振圖譜更顯示其逆磁的特性，此外由循環伏安法可以看出錯合物(1) 在+0.21伏特時有一個不可逆的氧化反應，而錯合物(2)在+1.10伏特以及-0.68伏特各有一個可逆的氧化還原對。

關鍵字

釕三核 ； 金屬串 ； 立障配位基 ； 異三核 ； 釕鉬釕

並列摘要

In recent years, scientists has fascinated with the concept of single-molecole conducting wire with the advancement of nanotechnology. In this thesis, we focus on extended metal-atom chain about trinuclear second-row transition metal string complexes with bulky ligand Hmnpo (7-methyl-1,8-naphthyridin-2(1H)-one). [Ru3(mnpo)4Cl](PF6) (1) and [RuMoRu(mnpo)4Cl](PF6) (2) have been successfully synthesized. Complex 2 is the first synthesized RuMoRu trinuclear string complex. The molecular structure show that the metal-atoms chains in these complexes are nearly non-helically coordinated by four deprotonated ligands. Due to the steric effect of Hmnpo, the displacement of one of the ligands is inevitable, leaving a nitrogen atom on naphthyridine remain uncoordinated. According to the molecular orbital model of tri-metal-atom chain described previously1, the electronic configurations of both Complex 1 and 2 results in the diamagnetism and the bond order is 1.5 between adjacent metal ions. The crystal structures show that the Ru–Ru and Ru–Mo bond lengths is 2.2699(14), 2.2753(14) Å in (1) and 2.2552(12), 2.2694(13) Å in (2), respectively, which is corresponding to a bond order of 1.5 between adjacent metal as expected. NMR and EPR spectrum of (2) reveals the diamagnetism of the complexes. Cyclic voltammetry shows that Complex 1 undergoes an irreversible oxidative process at E1/2 = 0.22V, while Complex 2 exhibits two reversible redox couples.

並列關鍵字

triruthenium ； trinuclear ； bulky ligand ； heteronuclear

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