含甲咪配位基之金屬化合物:四核金屬團簇與配位高分子

本論文主要探討含甲咪配位基之四核金屬團簇與配位高分子的結構與特性，共分五部分: 第一部分: 利用N,N’-bis(pyridine-4-yl)formamidine (4-Hpyf) 甲咪配位基，和含不同鹵素的二鹵化汞HgX2 (X = Cl, Br 與 I) 反應生成二維網狀的配位高分子{[Hg(4-pyf)2]•(THF)}n，1，以及ㄧ維螺旋鏈狀的配位高分子{[HgBr2(4-Hpyf)]•(MeCN)}n，2，和{[HgI2(4-Hpyf)]•(MeCN)}n， 3。化合物2的鏈狀結構以N-H---Br的氫鍵作用力，而化合物3以互補的雙N-H---N氫鍵連結，兩者皆形成二維具sql拓譜學的超分子網狀結構。化合物1的放射光譜位於448 nm，而化合物2與3分別為432與445 nm。利用理論計算得知，化合物1是來自於π → π*的躍遷，而化合物2與3是來自於鹵素之未鍵結的p軌域躍遷至配位基的π*軌域 (n → π*)。第二部分:利用Mo2(4-pyf)4， 4，與HgBr2、HgI2和HgCl2反應，可以分別得到第一個具有鉬-鉬四重鍵的二維或三維之異核金屬配位高分子[Mo2(4-pyf)4(HgBr2)2•0.5CH2Cl2]n，5、[Mo2(4-pyf)4(HgI2)2]n•0.5CH3OH]n，6，及[Mo2(4-pyf)4(HgCl2)3.6]n， 7。化合物5和6為二維同樣構型的化合物，可簡化成sql拓譜學結構，而化合物7為三維的配位高分子，其拓譜學結構為(32•4)2(34•42•63•74•82)(34•69•79•85•9)。如果不考慮電子密度分布不均的汞原子，此配位高分子則為雙節點的(4,8)-c 4,8T27，(32•53•6)(34•44•512•67•7)之拓譜學結構。利用SEM-EDS鑑定金屬原子分布比例，結果顯示與單晶結構相符。第三部分:利用一步水熱合成法，以起始物4-aminopyridine和triethylorthoformate與二價醋酸銅，分別在丙酮、二甲基甲醯胺、四氫呋喃、甲醇和乙醇溶劑下反應得到兩種不同構型的二維網狀結構，anti-{[Cu(4-pyf)]•ACT}n，8a、anti-{[Cu(4-pyf)]•DMF}n，8b、anti-{[Cu(4-pyf)]•THF]}n，8c、syn-{[Cu4(4-pyf)4]•2MeOH}n，9a，和以及syn-{[Cu4(4-pyf)4]•2EtOH}n，9b。若上述配方額外加入CuX2 (X = BF4- 與 ClO4-)，於乙醇下反應可得到三維的配位高分子， syn-{[Cu3(4-pyf)2](BF4)•2H2O•EtOH}n，10a，和syn-{[Cu3(4-pyf)2](ClO4)•EtOH}n，10b。化合物8a – 10b是第一個具有銅-銅金屬作用力的二維及三維的甲咪配位基之配位高分子。藉由溶劑置換可於二維anti- 和 syn-的配位高分子中觀察到可逆的晶體之間的轉換。而將8c溫度提高時，可以得到中間體syn-{[Cu4(4-pyf)4]•2THF}n，9c。進一步加熱去除溶劑則為不可逆的anti到syn的轉換。無溶劑的產物為具syn構型的化合物9d及9e。螢光光譜中，syn的化合物皆具有放光的性質，而anti的化合物並沒有偵測到放光的現象，這顯示銅-銅金屬作用力於8a – 10b中似乎並不會影響放光機制。二維的anti和syn的化合物具有未鍵結的氮原子，因此可以利用Cd---N的吸引力吸附Cd金屬鹽類。第四部分:透過逐步反應得到四核與二維的含金和銀與甲咪配位基之無機錯合物，分別為[Au4(4-pyf)4]•4(CH3OH)， 11、[Au4(pmf)4]， 12與[Ag4(pmf)4]，13，Hpmf = N,N’-bis(pyrimidine-2-yl)formamidine，以及配位高分子[Ag2(OAc)(4-pyf)]n，14，和{[Ag2(4-pyf)2]•(THF)}n，15。化合物11、12和13為四核的化合物，具有金屬-金屬作用力，而化合物14為二維的層狀結構，化合物15則是一維的配位高分子。四核的化合物在UV燈下發出藍綠光，此為dσ*/δ* → pπ*所造成的放光機制。化合物11 – 15的放光生命週期為1.06 – 49.15 ns，這些較短的生命週期顯示此放光為螢光的放射。有趣的是，化合物14在固態時放出白光，其CIE的座標為(0.30, 0.38)，相當接近於純白光(0.33, 0.33)。第五部分:利用一步水熱合成法，分別將2-, 3- 和4-(aminomethyl)pyridine 與 triethyl orthoformate 和 Cu(O2CCH3)2，於充滿氮氣的甲醇溶液中進行反應，可得到有機化合物 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz)，以及兩個含N2-配位基的三維配位高分子，分別為[Cu2.5(3-mpyf)(N2)1.5]n，16，和{[Cu3(4-Hmpyf)(N2)3]•(CH3OH)}n，17。化合物16與17的銅離子，分別以3-mpyf-橋接與N2-配位基橋接，其銅與銅之間的距離分別為2.5605(8) 與2.4460(13) Å，顯示有銅-銅金屬作用力的存在。化合物16之氮氣陰離子與銅原子之間的鍵結模式為end-on-dinuclear，形成雙節點的(5373)2(5482)的拓譜學結構；而化合物17的氮氣陰離子與銅原子有兩種不同的鍵結模式，分別為end-on-dinuclear和end-on-trinuclear，進而形成雙節點的(53)4(5864788494)2-3,8T16的拓譜學結構。本論文並利用熱分析、紅外線光譜以及拉曼光譜鑑定N2-陰離子。

關鍵字

四核金屬團簇；甲咪配位基；配位高分子

並列摘要

This dissertation discusses the structures and properties of tetranuclear clusters and coordination polymers supported by the formamidinate ligands, which can be divided into five parts. Part 1: Reactions of N,N’-bis(pyridine-4-yl)formamidine (4-Hpyf) with HgX2 (X = Cl, Br and I) afforded 2D coordination network {[Hg(4-pyf)2]•(THF)}n, 1, and 1D helical chains {[HgBr2(4-Hpyf)]•(MeCN)}n, 2, and {[HgI2(4-Hpyf)]•(MeCN)}n, 3, which have been structurally characterized by X-ray crystallography. Complex 1 shows 2D layers with the {44•62}-sql topology and complexes 2 and 3 are helical chains that show striking feature in their supramolecular structures. While the helical chains of 2 are linked through N-H---Br hydrogen bonds, those of 3 are linked through self-complementary double N-H---N hydrogen bonds, resulting in 2D supramolecular structures with sql topology for both complexes. The bromide and iodide anions play similar role in determining the crystal structures, while the bromide anion is distinct, suggesting that the structure-determining factors are the size and electronegativity of the halide anion. The emission spectrum of 1 exhibits a board band at 448 nm upon excitation at 381 nm, and those of 2 and 3 show emissions at 432 and 445 nm upon excitation at 344 and 348 nm, respectively. Density function theory (DFT) calculation indicates that the emission of 1 is due to intraligand π → π* charge transfer between two different 4-pyf- ligands, whereas those of 2 and 3 are due to the charge transfer from non-bonding p-type orbitals of the halide anions to π* orbitals of the 4-pyf- ligands (n → π*). Part 2: Reactions of Mo2(4-pyf)4, 4, with HgX2 (X = Br, I and Cl) afforded [Mo2(4-pyf)4(HgBr2)2•CH3OH]n, 5, [Mo2(4-pyf)4(HgI2)2]n•CH3OH]n, 6, and [Mo2(4-pyf)4(HgCl2)3.6]n, 7, respectively, which are the first 2D and 3D heteronuclear coordination networks based on the quadruple-bonded dimolybdenum units. Complexes 5 and 6 form 2D nets with the sql topology, whereas complex 7 results in a novel 3,6,8-connected trinodal net with point symbol (32•4)2(34•42•63•74•82)(34•69•79•85•9). In a more conservative view, if the disordered Hg atom is not considered, the underlying net becomes the binodal (4,8)-c 4,8T27 with point symbol (32•53•6)(34•44•512•67•7). The Mo/Hg molar ratio in these complexes derived from SEM-EDS matches quite well with those from single crystal X-ray crystallography. Part 3: One-pot solvothermal reactions of 4-aminopyridine and triethylorthoformate with Cu(O2CCH3)2 in acetone (ACT), dimethylformamide (DMF), tetrahydrofuran (THF), methanol (MeOH) and ethanol (EtOH) afforded 2D coordination networks anti-{[Cu(4-pyf)]•ACT}n, 8a, anti-{[Cu(4-pyf)]•DMF}n, 8b, anti-{[Cu(4-pyf)]•THF]}n, 8c, syn-{[Cu4(4-pyf)4]•2MeOH}n, 9a, and syn-{[Cu4(4-pyf)4]•2EtOH}n, 9b, whereas the reaction of Cu(O2CCH3)2, 4-aminopyridine, triethylorthoformate and CuX2 (X = BF4- and ClO4-) in ethanol gave the 3D coordination networks syn-{[Cu3(4-pyf)2](BF4)•2H2O•EtOH}n, 10a and syn-{[Cu3(4-pyf)2](ClO4)•EtOH}n, 10b, respectively, which were characterized by X-ray crystallography. Complexes 8a – 10b are the first 2D and 3D coordination networks showing closed-shell Cu(I)---Cu(I) interactions that are supported by the formamidinate ligands. Reversible crystal-to-crystal transformations were observed for the 2D anti- and syn-coordination networks upon solvent exchange. Irreversible anti to syn crystal-to-crystal transformations can be shown upon solvent removal and the important intermediate, syn-{[Cu4(4-pyf)4]•2THF}n, 9c, that verifies the temperature-dependent transformation was structurally characterized. The configurations of the structures have significant influences on the emission properties. While the syn-complexes show broad emissions, those of the anti-complexes are not detectable, indicating cuprophilicity is unlikely to play significant roles in determining the emissions of 8a – 10b. The 2D anti- and syn-complexes that show outwardly dangling pyridyl rings may adsorb the Cd salts through Cd---N interactions. Part 4: Reactions of Au(I) and Ag(I) metal salts with formamidine ligands afforded complexes of the types: [Au4(4-pyf)4]•4(CH3OH) [4-Hpyf = N,N’-bis(pyridine-4-yl)formamidine], 11, [Au4(pmf)4] [Hpmf = N,N’-bis(pyrimidine-2-yl)formamidine], 12, [Ag4(pmf)4], 13, [Ag2(OAc)(4-pyf)]n, 14, and {[Ag2(4-pyf)2]•(THF)}n, 15, which have been structurally characterized by X-ray crystallography. Complexes 11, 12, and 13 are tetranuclear, showing aurophilicity or argentophilicity, whereas 14 forms 2D layer and 15 exhibits a 1D chain. The tetranuclear complexes show bright blue-green luminescences under UV light, which can be ascribed to dσ*/δ* → pπ* transitions. The short lifetimes of 1.06 – 49.15 ns for 11 – 15 indicate that the emissions belong to fluorescence. Most interestingly, complex 14 shows the white luminescent emission in solid-state and the CIE coordinate of (0.30, 0.38) is similar to that of the white light at (0.33, 0.33). Part 5: The one-pot solvothermal reactions of 2-, 3- and 4-(aminomethyl)pyridine with triethyl orthoformate and Cu(O2CCH3)2 in methanol solutions saturated with nitrogen gas afforded the organic compound 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz), and the first 3D coordination polymers supported by the dinitrogen anions, [Cu2.5(3-mpyf)(N2)1.5]n [3-Hmpyf = N,N’-bis(pyridine-3-ylmethyl)formamidine], 15, and {[Cu3(4-Hmpyf)(N2)3]•(CH3OH)}n [4-Hmpyf = N,N’-bis(pyridine-4- ylmethyl)formamidine], 16, respectively, which were characterized by X-ray crystallography. Both of the complexes show cuprophilicity with Cu(I)---Cu(I) distances of 2.5605(8) and 2.4460(13) Å. The dinitrogen anions of 16 adopt the end-on-dinuclear bonding mode, resulting in a novel 4,4-connected binodal net with the (5373)2(5482) topology, whereas those of 17 displays two types of the bonding modes involving end-on-dinuclear and end-on-trinuclear, resulting in a 3,8-connected binodal net with the (53)4(5864788494)2-3,8T16 topology. Their thermal properties, IR and Raman spectra confirm the formation of the N2- anions.

並列關鍵字

formamidinate ligand ； coordination polymer ； tetranuclear complex

參考文獻

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國際替代計量

含甲咪配位基之金屬化合物:四核金屬團簇與配位高分子

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