含十六族元素 (硫、碲) 與過渡金屬 (錳、鐵、銅) 團簇化合物之合成、結構、化性及半導體性質
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2020
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S−Mn−CO 系統
利用 S powder 與 Mn2(CO)10 以莫耳比 5：1 於 4 M 之鹼性溶液中反應，可生成一含硫醇官能基之化合物 [(μ-HS)(μ3-S2)2Mn3(CO)9]2─ (1)，並從電化學上，發現其具有豐富的氧化訊號。因此，將錯合物 1 加入有機氧化試劑 CH2Cl2 於室溫下反應，可生成一 CH2 片段橋接之以雙 HS5Mn3(CO)9 為基底的化合物 [{(μ-HS)(μ3-S2)2Mn3(CO)9}2(CH2)]2─ (2)。除了有機氧化試劑，化合物 1也可與含自由基的 TEMPO 試劑於 0 oC 下進行反應，生成二聚化之似啞鈴型化合物 [(μ3-S2)4(μ4-S2)Mn6(CO)18]4─ (3) 並伴隨 TEMPO-H 的產生，同時可藉由 GC-MS 進行偵測。經由 X-ray 解析可知，化合物 3 可視為兩個 (μ3-S2)2Mn3(CO)9 的單體藉由中心 μ4-η1,η1,η1,η1-S−S 之鍵串接而成。此外，若進一步將化合物 3 與氫氣於 60 oC 下反應，則可成功轉換為含硫醇官能基之化合物 1，並藉由 1H NMR 偵測 hydride 訊號。有趣的是，經由 Evans method 發現，符合電子數之化合物 3 具有兩個未成對電子 (S = 1)，並藉由電子順磁共振光譜 (EPR) 顯示其磁性表現於金屬錳原子上。另一方面，於化合物 3 的固態堆疊圖可發現，可以看到有三種 C−H···O 的非典型氫鍵的作用力: CH([Et4N]+)···O(carbonyl)、CH([Et4N]+)···O(DMF) 和 CH(DMF)···O(DMF)，藉由這些分子間弱作用力可將分子型化合物 3 與其陽離子和配位溶劑分子串接，延伸形成二維的超分子結構。透過固態紫外光光譜量測可知化合物 13 能隙介於 2.202.31 eV，顯示此系列化合物具有半導體性質。最後，上述化合物之生成、轉換、磁性表現及電化學亦藉由理論計算進一步驗證。
S−Fe−Cu 系統
利用 [Et4N]2[SFe3(CO)9] 及 [Cu(MeCN)4][BF4] 與不同長度碳鏈之含氮配體 4,4’-dipyridine (dpy)、1,2-bis(4-dipyridyl)ethane (bpea)、4,4’-trimethylenedipyridine (bpp) 或 1,2-bis(4-dipyridyl)ethene (bpee) 以劑量比的方式進行三組件 (three-components) 溶劑輔助研磨 (liquid-assisted grinding, LAG)，可分別形成含硫之混合鐵銅羰基一維 zigzag 鏈狀聚合物 [SFe3(CO)9Cu2(dpy)3]n (2)、[SFe3(CO)9Cu2(bpea)]n (3) 和 [SFe3(CO)9Cu2- (bpee)]n (6)、以及二維蜂巢狀聚合物 [SFe3(CO)9Cu2(MeCN)(dpy)1.5]n (1)、[SFe3(CO)9Cu2(bpea)2]n (4)、[SFe3(CO)9Cu2(bpp)2]n (5) 和 [SFe3(CO)9Cu2- (bpee)3.5·MeCN)]n (8) 及聚合物 [SFe3(CO)9Cu2(bpee)2]n (7-unknown)。特別的是，將一維聚合物 2 和二維聚合物 4 個別加入 1 當量 [SFe3(CO)9]2─ 及 2 當量 [Cu(MeCN)4]+ 可轉換為二維聚合物1 和一維聚合物 3。再者，將聚合物 2 和 3 分別加入1.5 當量 dpy 及 1 當量 bpea 可轉換回聚合物 2 與 4，是為可逆的維度轉換關係。藉由固態紫外光光譜量測可得聚合物 17-unknown 能隙範圍落在 1.63−1.80 eV 之間，皆具有半導體的特性。另一方面，針對本系列 S−Fe−Cu 聚合物之 Cu 金屬的氧化態，進行高解析 X-ray 光電子能譜 (XPS) 和 X-ray 吸收近邊緣結構光譜 (XANES) 的量測，結果顯示聚合物 17-unknown 中的 Cu 原子氧化態介於 Cu(0) 和 Cu(I) 價之間。此外，藉由近紅外光螢光光譜量測，聚合物 17-unknown 的放光位置介於 18222132 nm，皆具有特殊近紅外光的放光特性。
Te−Mn−CO 系統
利用 Te powder、Mn2(CO)10 與 Et4NBr 以劑量比 10: 3: 4 於 1 M 之 KOH/MeOH/MeCN 混合溶液下加熱迴流，可得一似啞鈴型的順磁性 (S = 1)化合物 [Te10Mn6(CO)18]4─ (1)。化合物 1 可視為兩個Mn3(μ3-Te2)2(μ-Te)(CO)9 基團藉由一組 μ4-η1,η1,η1,η1-Te22─ 片段串接之雙聚物，其中化合物 1 中的五組 Te22─ 片段具有三種不同鍵結模式，分別為μ4-η1,η1,η1,η1-、μ3-η1,η1,η1- 和 μ3-η1,η1,η2-Te22─。若進一步將化合物 1 與親電試劑 MeI 於 MeCN 溶液中反應，可得兩個甲基加成之化合物 [Te10Mn6(CO)18(CH3)2]2─ (2)。X-ray 結構解析可知，化合物 2 之主體結構與 1 相似，其引入之甲基片段則加成至化合物 1 中 μ3-η1,η1,η1-Te22─ 片段之兩配位的 Te 原子上。根據 DFT 理論計算顯示，此為一價數控制 (charge controlled) 之反應。此外，若將化合物 1 加入過量的有機氧化試劑 CH2Cl2 於 60 oC 的 MeCN 溶液中反應，可生成一似籃型 (basket-like) 化合物 [Te6Mn3(CO)9(CH2)]─ (3)。由 X-ray 構造解析發現化合物 3 由三個 Mn(CO)3 片段所組成，並由一組 μ3-Te2 和一組 μ3-Te3CH2Te 片段所連接而成的籃型化合物。反之，此則為一軌域控制 (orbital controlled) 之反應。此外，125Te 核磁共振結果顯示，具有 Te10Mn6 金屬基團之化合物 1 和 2 皆具有豐富的 4 組訊號，且化合物 2 較 1 往低磁場移動 (downfield shift)，是由於化合物 2 的電子密度小於化合物 1。另一方面，透過化合物 1−3 之電化學表現，顯示化合物 1 的第一組還原峰在 −0.132 V 相較於化合物 2 及3 之第一組還原峰分別在 −1.142 V 及 −0.796 V 更為接近 0 V，推測化合物 1 具有更豐富的化學反應性。再者，利用固態紫外光光譜儀量測此系列化合物的能隙，驚訝的發現，化合物 1−3 之能隙極低並落在 1.431.70 eV 範圍內，顯示其具有半導體特性。最後，上述的結果亦搭配密度泛函數理論 (DFT) 計算加以佐證。
S-Mn−CO system The reaction of S powder with Mn2(CO)10 in a molar ratio of 5: 1 in 4 M KOH/MeOH solutions led to the formation of the thiol group-containing S−Mn carbonyl complex [(μ-HS)(μ3-S2)2Mn3(CO)9]2─ (1). When 1 reacted with the oxidizing agent CH2Cl2 at room temperature, the CH2-bridged di-HS5Mn3-based cluster [{(μ-HS)(μ3-S2)2Mn3(CO)9}2(CH2)]2─ (2) was produced in moderate 60% yields. In addition, if complex 1 was treated with the radical-trapping agent TEMPO, the dimeric cluster [(μ3-S2)4(μ4-S2)Mn6(CO)18]4─ (3) was formed, accompanied with the formation of TEMPO-H which was further detected by GC-MS. X-ray analysis showed that 3 possessed two (μ3-S2)2Mn3(CO)9 moieties bridged by a μ4-η1,η1,η1,η1-S22 unit, in which an inversion center was located at the midpoint of the central SS bond to give a dumbbell-like conformation. Complex 3 could also be reconverted to complex 1 upon the addition of H2 in MeCN at 60 oC, which was further evidenced by 1H NMR. According to Evans method analysis, the electron-precise complex 3 was found to possess paramagnetic properties, with S = 1 (μeff = 2.57 μB) at room temperature. The unusual paramagnetism of 3 arose from two types of the Mn atoms in different oxidation states, as further determined by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surprisingly, the diffuse reflectance spectra showed that complexes 1−3 exhibited semiconducting characteristics with the energy gap in the range of 2.202.31 eV, in which complex 3 possessed the lowest energy gap, mainly attributed to its intramolecular C−H(DMF)···O(DMF) and intermolecular C−H(Et4N)···O(carbonyl) and C−H(Et4N)···O(DMF) interactions in the solid state. Finally, the syntheses, reactivity, structural transformations, optical properties, and electrochemical characteristics of these S−Mn−CO clusters were further elucidated by DFT calculations. S−Fe−Cu system A series of semiconducting S−Fe−CO cluster-incorporated Cu-based coordination polymers, namely, 1D zigzag polymers [SFe3(CO)9Cu2(dpy)3]n (dpy = 4,4’-dipyridine, 2) and [SFe3(CO)9Cu2(L)]n (L = 1,2-bis(4-pyridyl)ethane (bpea), 3; L = 1,2-bis(4-pyridyl)ethylene (bpee), 6), 2D honeycomb-like polymers [SFe3(CO)9Cu2(dpy)1.5]n (1), [SFe3(CO)9Cu2(bpee)3.5]n (8) and [SFe3(CO)9Cu2(L)2]n (L = bpea, 4; L = 1,3-bis(4-pyridyl)propane (bpp), 5), as well as the polymer [SFe3(CO)9Cu2(bpee)2]n (7-unknown) have been synthesized via the liquid-assisted grinding (LAG) from the three-component reactions of [SFe3(CO)9]2− and [Cu(MeCN)4]+ with conjugated or conjugation-interrupted dipyridyl linkers, respectively. The reversible dimensionality transformations between 1D polymer 2 and 2D polymer 1 and between 2D polymer 4 and 1D polymer 3 were also successfully achieved via the mechanochemical synthesis by the addition of stoichiometric amounts of [SFe3(CO)9]2− and [Cu(MeCN)4]+ or dipyridyl. Notably, the diffuse reflectance spectra showed that 1–7-unknown exhibited semiconducting characteristics with the energy gap in the range of 1.631.80 eV. In addition, these synthesized 1D and 2D polymers 1–7-unknown all possessed rare short-wavelength (λmax = 1822−2132 nm) infrared emission properties. The intriguing structure–property relationships were further demonstrated by a significant oxidation state change of the Cu atom by XPS and Cu K-edge XANES. Te-Mn−CO system The one-pot reaction of Te powder, Mn2(CO)10, and [Et4N]Br were mixed in a ratio of 10: 3: 4 in 1 M KOH led to the formation of the dumbelled-like complex [Te10Mn6(CO)18]4─ (1). Cluster 1 can be further functionalized by methylation to produce the di-CH3-incorporated Te10Mn6-based cluster [Te10Mn6(CO)18- (CH3)2]2− (2) upon the treatment with 2 equiv of CH3I. X-ray analysis showed that cluster 2 possessed a two CH3-bound Te10Mn6-based structure, where the methyl groups each were bonded to the terminal Te atoms in the Te10Mn6 metal core. In addition, when 1 reacted with excess organic oxidizing agent CH2Cl2, the CH2-inserted Te6Mn3-based complex [Te6Mn3(CO)9(CH2)]─ (3) was produced. X-ray analysis revealed that cluster 3 consisted of three Mn(CO)3 fragments, which were further connected by one μ3-Te2 and μ3-Te3CH2Te to give a basket-like cluster. According to density functional theory (DFT) calculations, the terminal Te atoms in 1 are mostly negatively-charged, which led to a selective charge-controlled methylation. In contrast, the higher-energy SOMO of 1 has a large contribution of the antibonding interaction of the p orbitals of the central two Te atoms, whichgave a smaller sized orbital-controlled product 3 upon the reaction with CH2Cl2. In addition, 125Te NMR analysis showed that the Te10Mn6-based clusters 1 and 2 both exhibited four 125Te resonances, where all chemical shifts in 2 were dramatically downfield shifted compared to those of 1, attributed to the lower electron-density of the di-anion 2 in comparison to the tetra-anion 1. Further, the electrochemical properties of complexes 1–3 were further studied by differential pulse voltammetry measurments, in which the first reduction potential of the tetra-anionic cluster 1 (−0.132 V) was close to 0 V in comparison with that of the di-anionic cluster 2 (−1.142 V) and the anionic complex 3 (−0.796 V), indicative of the versatile chemical reactivities of 1. Moreover, the diffuse reflectance spectra showed that complexes 1−3 exhibited semiconducting characteristics with the energy gaps in the range of 1.431.70 eV. Finally, the nature, syntheses, optical properties, and electrochemical behaviors of these resultant Te−Mn−CO complexes 1–3 were elucidated by DFT calculations.
S-Mn−CO system The reaction of S powder with Mn2(CO)10 in a molar ratio of 5: 1 in 4 M KOH/MeOH solutions led to the formation of the thiol group-containing S−Mn carbonyl complex [(μ-HS)(μ3-S2)2Mn3(CO)9]2─ (1). When 1 reacted with the oxidizing agent CH2Cl2 at room temperature, the CH2-bridged di-HS5Mn3-based cluster [{(μ-HS)(μ3-S2)2Mn3(CO)9}2(CH2)]2─ (2) was produced in moderate 60% yields. In addition, if complex 1 was treated with the radical-trapping agent TEMPO, the dimeric cluster [(μ3-S2)4(μ4-S2)Mn6(CO)18]4─ (3) was formed, accompanied with the formation of TEMPO-H which was further detected by GC-MS. X-ray analysis showed that 3 possessed two (μ3-S2)2Mn3(CO)9 moieties bridged by a μ4-η1,η1,η1,η1-S22 unit, in which an inversion center was located at the midpoint of the central SS bond to give a dumbbell-like conformation. Complex 3 could also be reconverted to complex 1 upon the addition of H2 in MeCN at 60 oC, which was further evidenced by 1H NMR. According to Evans method analysis, the electron-precise complex 3 was found to possess paramagnetic properties, with S = 1 (μeff = 2.57 μB) at room temperature. The unusual paramagnetism of 3 arose from two types of the Mn atoms in different oxidation states, as further determined by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surprisingly, the diffuse reflectance spectra showed that complexes 1−3 exhibited semiconducting characteristics with the energy gap in the range of 2.202.31 eV, in which complex 3 possessed the lowest energy gap, mainly attributed to its intramolecular C−H(DMF)···O(DMF) and intermolecular C−H(Et4N)···O(carbonyl) and C−H(Et4N)···O(DMF) interactions in the solid state. Finally, the syntheses, reactivity, structural transformations, optical properties, and electrochemical characteristics of these S−Mn−CO clusters were further elucidated by DFT calculations. S−Fe−Cu system A series of semiconducting S−Fe−CO cluster-incorporated Cu-based coordination polymers, namely, 1D zigzag polymers [SFe3(CO)9Cu2(dpy)3]n (dpy = 4,4’-dipyridine, 2) and [SFe3(CO)9Cu2(L)]n (L = 1,2-bis(4-pyridyl)ethane (bpea), 3; L = 1,2-bis(4-pyridyl)ethylene (bpee), 6), 2D honeycomb-like polymers [SFe3(CO)9Cu2(dpy)1.5]n (1), [SFe3(CO)9Cu2(bpee)3.5]n (8) and [SFe3(CO)9Cu2(L)2]n (L = bpea, 4; L = 1,3-bis(4-pyridyl)propane (bpp), 5), as well as the polymer [SFe3(CO)9Cu2(bpee)2]n (7-unknown) have been synthesized via the liquid-assisted grinding (LAG) from the three-component reactions of [SFe3(CO)9]2− and [Cu(MeCN)4]+ with conjugated or conjugation-interrupted dipyridyl linkers, respectively. The reversible dimensionality transformations between 1D polymer 2 and 2D polymer 1 and between 2D polymer 4 and 1D polymer 3 were also successfully achieved via the mechanochemical synthesis by the addition of stoichiometric amounts of [SFe3(CO)9]2− and [Cu(MeCN)4]+ or dipyridyl. Notably, the diffuse reflectance spectra showed that 1–7-unknown exhibited semiconducting characteristics with the energy gap in the range of 1.631.80 eV. In addition, these synthesized 1D and 2D polymers 1–7-unknown all possessed rare short-wavelength (λmax = 1822−2132 nm) infrared emission properties. The intriguing structure–property relationships were further demonstrated by a significant oxidation state change of the Cu atom by XPS and Cu K-edge XANES. Te-Mn−CO system The one-pot reaction of Te powder, Mn2(CO)10, and [Et4N]Br were mixed in a ratio of 10: 3: 4 in 1 M KOH led to the formation of the dumbelled-like complex [Te10Mn6(CO)18]4─ (1). Cluster 1 can be further functionalized by methylation to produce the di-CH3-incorporated Te10Mn6-based cluster [Te10Mn6(CO)18- (CH3)2]2− (2) upon the treatment with 2 equiv of CH3I. X-ray analysis showed that cluster 2 possessed a two CH3-bound Te10Mn6-based structure, where the methyl groups each were bonded to the terminal Te atoms in the Te10Mn6 metal core. In addition, when 1 reacted with excess organic oxidizing agent CH2Cl2, the CH2-inserted Te6Mn3-based complex [Te6Mn3(CO)9(CH2)]─ (3) was produced. X-ray analysis revealed that cluster 3 consisted of three Mn(CO)3 fragments, which were further connected by one μ3-Te2 and μ3-Te3CH2Te to give a basket-like cluster. According to density functional theory (DFT) calculations, the terminal Te atoms in 1 are mostly negatively-charged, which led to a selective charge-controlled methylation. In contrast, the higher-energy SOMO of 1 has a large contribution of the antibonding interaction of the p orbitals of the central two Te atoms, whichgave a smaller sized orbital-controlled product 3 upon the reaction with CH2Cl2. In addition, 125Te NMR analysis showed that the Te10Mn6-based clusters 1 and 2 both exhibited four 125Te resonances, where all chemical shifts in 2 were dramatically downfield shifted compared to those of 1, attributed to the lower electron-density of the di-anion 2 in comparison to the tetra-anion 1. Further, the electrochemical properties of complexes 1–3 were further studied by differential pulse voltammetry measurments, in which the first reduction potential of the tetra-anionic cluster 1 (−0.132 V) was close to 0 V in comparison with that of the di-anionic cluster 2 (−1.142 V) and the anionic complex 3 (−0.796 V), indicative of the versatile chemical reactivities of 1. Moreover, the diffuse reflectance spectra showed that complexes 1−3 exhibited semiconducting characteristics with the energy gaps in the range of 1.431.70 eV. Finally, the nature, syntheses, optical properties, and electrochemical behaviors of these resultant Te−Mn−CO complexes 1–3 were elucidated by DFT calculations.
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