含錳或鐵之對稱型混金屬串與鈷鉑銅異三核混金屬串 之合成與鑑定

Symmetrical Heteronuclear Metal Strings Containing Mn or Fe and Co-Pt-Cu Heterotrinuclear Metal String

余立中(Li-Chung Yu)

指導教授 ： 彭旭明

國立臺灣大學/理學院/化學研究所/博士(2016年)

https://doi.org/10.6342/NTU201601134

摘要

奈米金屬導線在現今追求微小化的半導體工業中，為熱門研究題目之一，有應用於奈米機器人元件的潛力，且文獻顯示混入不同金屬的異核金屬串具有特別的導電性質。目前對稱型異核金屬串多由一鍋法合成，而本論文也成功使用一鍋法，合成出以dpa(dipyridylamine)為配基，d8金屬(Ni、Pd、Pt)於金屬串中間位置，Mn或Fe於兩端點位置的對稱型異核混金屬串MnNiMn(dpa)4Cl2 (3)、MnPdMn(dpa)4Cl2 (4)、MnPtMn(dpa)4Cl2 (5)、FeNiFe(dpa)4Cl2 (6)、FePdFe(dpa)4Cl2 (7)，以及從CdPtCd(dpa)4Cl2 (2)進行金屬置換得到FePtFe(dpa)4Cl2 (8)，所有化合物皆以全順向式的dpa螺旋環繞三個金屬成金屬直線型排列，對稱性D4的分子，這些金屬串皆顯示端點金屬間的反鐵磁性，分為兩個系列，其一為Mn、Fe、Co、Ni，隨著中心金屬原子序增加而反鐵磁性增加，其二為Cu，隨著中心金屬原子序增加而反鐵磁性降低，此差異來自於磁交換機制不同所產生，結構與磁性行為顯示，此系列中心為d8金屬的對稱行異核金屬串中，中心金屬原子序的增加會增強金屬串中金屬間的作用力，而藉由EPR的量測，可得到MnMMn(dpa)4Cl2的g值，與磁性擬合所得g值皆偏離Mn高自旋理論值2。
成功利用產率佳的CoPtCo(dpa)4Cl2 (1)與大量Cu(OAc)2反應，將於端點穩定度相對較大的Co成功置換成Cu，得到CoPtCu(dpa)4Cl2 (9)，由NMR可以鑑定化合物9為不對稱排列的金屬串，高解析質譜可以確定化合物9的組成，同樣也是以全順向式的dpa螺旋環繞三個金屬成金屬直線型排列，對稱性D4的分子，結構中有金屬失序的狀況，Co2+的配位環境與磁化率顯示，在150─300 K為Co2+的spin crossover，150 K以下顯露低自旋Co2+與Cu2+間為微弱反鐵磁作用力。

關鍵字

異核金屬串 ； 反鐵磁作用 ； 電子順磁共振光譜 ； 艾克斯光吸收光譜

並列摘要

Metal strings have attracted much attention of physicists and chemists because of their potential applications for the devices of nanoelectronics. Heteronuclear metal strings have their special properties of electronic conduction. In this work, the syntheses, crystal structures, and magnetic properties of seven trinuclear, heterometal string complexes stabilized by four dipyridylamide (dpa) ligands are reported. All compounds exhibit an approximate D4 symmetry and a linear metal framework helically wrapped by four syn-syn-type ligands. The center metal ions bond with the amide part of dpa in square-planar environment, and the outer metal ions bond with Cl and pyridine part of dpa in square-pyramidal environment. Compounds MnMMn(dpa)4Cl2 (M = Ni for 3, M = Pd for 4, M = Pt for 5) and FeMFe(dpa)4Cl2 (M = Ni for 6, M = Pd for 7, M = Pt for 8) show antiferromagnetic interaction between the terminal metal ions, and the 2J value increases with increasing atomic number of the central metal ion. This trend is the exact reverse of the trend observed for the CuMCu(dpa)4Cl2 (M = Cu3+, Pd2+, Pt2+) analogs. This observation may be explainable by the different magnetic coupling mechanisms between two series of compounds.
Co2+ has the higher stability at the terminal position in metal string than Co2+. In the reaction of CoPtCo(dpa)4Cl2 (1) and 20 eq Cu(OA)2, Co2+ can be replaced by Cu2+, and CoPtCu(dpa)4Cl2 (9) can be obtained. Compound 9 has the metal disorder in the structure. From NMR and Mass spectra, the unsymmetric metal arrangement and the components of compound 9 can be confirmed. Compound 9 shows antiferromagnetic interaction between the terminal Co2+ and Cu2+ at low temperature (4─150 K) and shows the spin crossover of Co2+ at high temperature (150─300 K).

並列關鍵字

heterometal EMACs ； antiferromagnetism ； EPR ； Ni L-edge absorption

參考文獻

37. S.-M. Peng, C.-C. Wang, Y.-L. Jang, Y.-H. Chen, F.-Y. Li, C.-Y. Mou and M.-K. Leung, J. Magn. Magn. Mater., 2000, 209, 80-83.

3. C. H. Yu, M. S. Kuo, C. Y. Chuang, G. H. Lee, S. A. Hua, B. Y. Jin and S. M. Peng, Chem. Asian. J., 2014, 9, 3111-3115.

5. M. Nippe and J. F. Berry, J. Am. Chem. Soc., 2007, 129, 12684-12685.

6. M. Nippe, E. Victor and J. F. Berry, Eur. J. Inorg. Chem., 2008, 2008, 5569-5572.

10. M. Nippe, Y. Turov and J. F. Berry, Inorg. Chem., 2011, 50, 10592-10599.