雙萘啶胺及其五核異金屬串分子之合成與研究

Syntheses and Studies of the Pentanuclear Heterometallic String Complexes with Binaphthyridylamine Ligand

許思絜(Ssu-Chieh Hsu)

指導教授 ： 彭旭明

國立臺灣大學/理學院/化學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701239

摘要

本論文主要是以具有豐富電化學性質之雙萘啶胺配基(Binaphthyridylamine, Hbna)為基底，藉由調控適當之第四列族之鉬或釕金屬與鎳金屬之當量比，合成出具導電性與具金屬金屬多重鍵的金屬串分子，並藉由儀器鑑定該分子與其導電度，再與實驗室過往一系列分子進行比較。
藉由先合成之2-amino-1,8-naphthyridine和2-chloro-1,8-naphthyridine由鈀金屬催化得雙萘啶胺配基。再將雙萘啶胺與Mo2(OAc)4或Ru2(OAc)4Cl進行高溫萘燒反應後再加入Ni(OAc)2•4H2O和軸向配基LiCl，可得異五核直線型金屬串分子[NiMo2Ni2(bna)4Cl2](PF6)3 (1)與[NiRu2Ni2(bna)4Cl2](ClO4)3 (3)，再將錯合物1加入NaNCS置換軸向可得[NiMo2Ni2(bna)4(NCS)2](PF6)3 (2)。利用單晶繞射儀可鑑定其結構，三個錯合物皆由四片脫氫之雙萘啶胺配基以全順向式之螺旋纏繞配位和金屬鍵結，整體皆為正三價化合物，且末端之鎳金屬屬四方角錐之五配位，中心鎳金屬則為平面四方之配位模式。其中錯合物1和2之萘啶上雙核鎳金屬為一二混價的正三價單元、其餘之鉬、鎳金屬則皆為正二價，其中在金屬的二與四位會發生失序，但依可參考其錯合物1與2之鉬鉬鍵長分別為2.133(2)與2.109(2) Å可知其存在著四重鍵的作用力。再者藉由紅外線光譜儀，可判斷因錯合物2具有2070 cm-1之C-N stretching訊號，確實有置換上軸向配基NCS-，且因其並未分裂可得知是與相同之金屬連接。
對於錯合物1和2，由磁性解析可知為反鐵磁性物質，其中推測中心之雙核鉬單元磁矩為S = 0，因而主要貢獻來自於萘啶上之混價雙核鎳單元(S = 3/2)與另一末端高自旋之鎳金屬(S = 1)，確實符合擬合分析之結果；而藉由循環伏安儀發現皆具有3對可逆之氧化還原對，推測其可再進一步還原成二價分子與氧化成四價和五價結構；由電子吸收光譜可見配基與金屬間和金屬與金屬間之躍遷訊號。
再者，藉由STM-bj方法可得錯合物2之單分子導電值為1.58(±1.61)x10-5 G0 ；電阻值為814 MΩ。

關鍵字

異核金屬串分子 ； 雙萘啶胺 ； 鉬鎳 ； 釕鎳 ； 金屬金屬多重鍵

並列摘要

The thesis foucused on extended metal atom chains (EMACs) about pentanuclear heterometallic string complexes with symmetric binaphthyridylamine which contained plentiful electronic properties, metal-metal multiple bond and conductivity.
[NiMo2Ni2(bna)4Cl2](PF6)3 (1), [NiMo2Ni2(bna)4(NCS)2](PF6)3 (2) and [NiRu2Ni2(bna)4Cl2](ClO4)3 (3) have been successfully synthesized by controlling proper ratio of Mo2(OAc)4/Ru2(OAc)4Cl and Ni(OAc)24H2O. All these materials have been characterized by Matrix-Assisted Laser Desotption Ionization Time-of-Flight Mass Spectrometer (MALDI-TOF-MS), X-ray Single Crystal of Diffractometer (XRD), Superconducting Quantum Interference Device Magnetometer (SQUID), fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-Visible Spectrometer (UV), and Cyclic voltammetry (CV).
The molecular structures reveals that metal ions(NiⅡ-Mo2Ⅳ-Ni2Ⅲ) in complexes are helically wrapped by four deprotonated ligand (bna-) and all coordinated in syn- syn form. Besides,we could observe the distance 2.133(2) and 2.109(2) for complex 1 and 2 between two Mo ions to show quadruple bond. Also, we can observe that remarkably short Ni-Ni distances (2.311 and 2.334 Å) for complex 1 and 2 indicate partial metal–metal bonding, which can be viewed as each complexes containing one mixed-valence [Ni2]3+ unit. Additionally, we found C-N strentching (2070 cm-1) for complex 2 by FT-IR to ensure that axial ligand would be switched to NCS-. For complex 3, we see di nickel unit has longer Ni-N distances to [NiRu2Ni2(tpda)4(NCS)2], so we assign complex 3 has mixed-valence [Ni2]3+ unit.
The magnetic measurements show that complex 1 and complex 2 is likely antiferromagnetic compounds (J = -45.6 cm-1 for complex 1 and J = -46.7 cm-1 for complex 2), and we assigned that the terminal nickel ion is high spin state (S = 1) and mixed-valence [Ni2]3+ unit (S = 3/2).
The results of cyclic voltammetry indicate the presence three reversible redox couples, so we can predict that [NiM2Ni2(bna)4X2]3+ (M = Mo、Ru, X = Cl、NCS) might be further oxidized to be [NiM2Ni2(bna)4X2]4+ and [NiM2Ni2(bna)4X2]5+ or reduced to be [NiM2Ni2(bna)4X2]2+.
The absorption spectra of complex 1, 2 and 3 are shown a broad peak in 500-700 nm regions that we could assign to be intervalence charge transfer (IVCT) system from mixed-valence [Ni2]3+ unit. For complex 3, we don’t observe that signal aroud 1000 nm which belongs [Ru2]5+, so we assign that [Ru2]4+ in complex 3.
The values of conductance 1.58(±1.61)x10-5 G0 and resistance 814 MΩ for complex 2 were determined by STM break-juction measurements, and these represent that the first conductance measurements of pentanuclear heterometallic string complexes with binaphthyridylamine ligand.

並列關鍵字

Heterometal string complex ； Binaphthyridylamine ； metal metal bond ； EMACs ； metal metal interation

參考文獻

[35] 鄭伊庭. (2016). 新型不對稱吡啶胺配基及其鎳金屬串與雙核釕錯合物之合成與研究. (碩士), 國立台灣大學.

[36] 華紹安. (2012). 直線型混價鎳金屬串與不對稱多核混金屬串之系列錯合物之合成與性質研究. (博士), 國立台灣大學.

[38] (a)Ting, T. C.; Hsu, L. Y.; Huang, M. J.; Horng, E. C.; Lu, H. C.; Hsu, C. H.; Jiang, C. H.; Jin, B. Y.; Peng, S. M.; Chen, C. H., Angew Chem Int Ed Engl 2015, 54 (52), 15734; (b)余聖謙. (2015). 三吡啶二胺(H2tpda)之四核釕與混釕鎳異金屬串錯合物之合成與研究. (碩士), 國立台灣大學.

[2] Olof Ramström, The Royal Swedish Academy of Science, 2016.

[4] Hofmann, K. A.; Bugge, G., Berichte der deutschen chemischen Gesellschaft 1908, 41 (1), 312.