剛性配基(Hdzp)及其三核釕金屬串之合成與研究

Syntheses and Studies of Triruthenium Metal String Complexes with Rigid Ligand (1,9-diazaphenoxazine)

劉昊諠(Hao-Hsun Liu)

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/NTU201900893

摘要

本篇論文主要利用一剛性配基Hdzp (1,9-diazaphenoxazine)來合成以釕金屬為金屬中心的非螺旋性三核金屬串錯合物，並透過X-ray單晶繞射、循環伏安法、磁性測量、電子吸收光譜、核磁共振儀與質譜儀來鑑定及探討其性質，並且利用STM break junction method來量測化合物之導電性。
以釕雙核錯合物(Ru2(OAc)4Cl)及釕單核錯合物(Ru(py)4Cl2)作為金屬起始物，並加入Hdzp (1,9-diazaphenoxazine)作為配基，並以萘(naphthalene)作為溶劑在高溫220 oC於氬氣(Ar)環境下反應2個小時，並加入NaNCS或LiCl作為軸向配基的來源。由於中性產物會在空氣中逐漸氧化，故加入[Fe(μ5-C5H5)2](PF6)將其進行氧化後，再利用管柱層析法將粗產物進行純化，最後透過擴散養晶的方式取得高純度產物及品質良好的單晶。
在經過單晶繞射解析後得到了兩個以不同軸向配基配位之三核釕金屬串錯合物結構[Ru3(dzp)4(NCS)2](PF6) (1)與[Ru3(dzp)4Cl2](PF6) (2)，並透過循環伏安法可知錯合物1在E1/2 = 0.20 V以及0.92 V有兩對可逆的氧化還原峰，其分別對應於[Ru3]7+/6+與[Ru3]8+/7+的氧化還原。經超導量子干涉儀進行磁性量測可知，錯合物1在300 K時的有效磁矩為μeff = 2.11 B.M.，與一個未成對電子(S = ½)的理論spin-only數值μspin-only = 1.73 B.M.相近，而錯合物1還原一電子後之錯合物3在300 K時的有效磁矩為μeff = 2.99B.M.，與兩個未成對電子(S = 1)的理論spin-only數值μspin-only = 2.83 B.M.相近。由電子吸收光譜發現錯合物1和2與配基相互比較，除了消光係數上升之外，同時還產生紅位移的現象，並額外產生和金屬有關的躍遷吸收訊號。
在導電性測量的部分，[Ru3(dzp)4(NCS)2](PF6) (1)的導電度為8.64(±4.35) x 10-4 G0，與實驗室傳統使用Hdpa所合成之[Ru3(dpa)4(NCS)2]+的電導值相比大約下降了一個數量級(10.2 (±2.2) × 10–3 G0)，詳細原因還需進一步經由理論計算證實。

關鍵字

分子導線 ； 金屬串 ； 剛性配基

並列摘要

In this research, we report the triruthenium metal string complexes with 1,9-diazaphenoxazine (Hdzp) ligand, and investigate the properties by X-ray diffraction, cyclic voltammetry, SQUID, electron absorption spectroscopy, NMR spectroscopy and mass spectroscopy. We also use STM break junction method to measure the conductance of complex 1.
In order to synthesize the trinuclear metal complexes [Ru3(dzp)4(NCS)2](PF6) (1) and [Ru3(dzp)4Cl2](PF6) (2), the Hdzp ligand is used to react with Ru2(OAc)4Cl and Ru(py)4Cl2 for two hours in naphthalene. Then, the NaNCS or LiCl salts is added to be the axial ligand. After the extraction from crude with DCM, the oxidizing reagent ferrocenium hexafluorophosphate (FcPF6) would be added to obtain the final products.
Based on X-ray structure characterization, we obtain two single crystal structures, [Ru3(dzp)4(NCS)2](PF6) (1) and [Ru3(dzp)4Cl2](PF6) (2). The cyclic voltammetry of complex 1 exhibits two reversible redox couples at E1/2 = 0.20 V and E1/2 = 0.92 V which are assigned to [Ru3]7+/6+ and [Ru3]8+/7+. Magnetic susceptibility measurements show that complex 1 and 3 are paramagnetic compound, and the value of μeff at 300 K are 2.11 B.M. and 2.99 B.M., respectively. It can be seen that complex 1 and 3 are likely in a spin state of S = 1/2 and S = 1. The result of electronic absorption spectra indicate that there are obviously different between Hdzp ligand and metal string complex. There are not only the increase of extinction coefficient but also the red shift of the absorption. Additionally, there are some transition which is related to the metal center in complex.
The conductance of complex 1 is 8.64(±4.35) x 10-4 G0 (14.9±7.5 MΩ), which is almost ten times less than the conductance of [Ru3(dpa)4(NCS)2]+ (10.2 (±2.2) × 10–3 G0, 1.27 (±0.28) MΩ). We will perform the DFT calculation to confirm the unexpected results.

並列關鍵字

molecular wire ； metal string ； rigid ligand

參考文獻

1. Aviram, A.; Ratner, M. A. Chem. Phys. Lett., 1974, 29, 277-283.

2. (a) Tour, J. M. Acc. Chem. Res., 2000, 33, 791.(b) Reed, M. A.; Tour, J. M. Sci. Am., 2000, 282, 86.

3. W. E. Roseveare. J. Am. Chem. Soc.1930, 52,2612

4. (a) Cotton, F. A.; Harris, C. B. Inorg. Chem., 1965, 4, 330.(b) Cotton, F. A.; Curtis, N. F.; Johnson, B. G.; Robinson, W. R. Inorg. Chem., 1965, 4, 326.

5. (a) Clouston, L. J.; Bernales, V.; Carlson, R. K.; Gagliardi, L.; Lu, C. C., Inorg. Chem. 2015, 54, 9263-9270.