多核含碲之第六族過渡金屬(鉬、鎢)羰基團簇物及含十六族 (硫、硒、碲) 三鐵羰基汞銅陰陽離子聚合物之合成、結構、化性及半導體性質探討

Abstract

1. Te-M−CO 系統 (M = Mo, W) 系統之研究由 Te 粉末 、M(CO)6 (M = Mo, W) 和Et4NBr在KOH/MeOH/MeCN 溶液中以不同比例下反應可合成一系列新穎多核含碲之第六族過渡金屬羰基團簇物，籠狀 [Et4N]4[Te7Mo6(CO)20] (1)、籃型 [Et4N]4[Te6Mo6(CO)15] (2a-Mo(CO)3) 與碗型化合物 [Et4N]4[Te6W5(CO)12] (2b)。 此系列化合物具高氧化性質，當化合物 1 與氧化試劑 I2 以莫耳比 1 : 1反應可合成車輪型結構 [Et4N]2[Te8Mo6(CO)18] (6)，而化合物 2b 與I2 以莫耳比 1 : 1反應則得到生成一新W‒W 金屬鍵的化合物 [Et4N]2[Te6W5(CO)12] (3b)。進一步將化合物 2a-Mo(CO)3 及2b與 I2 以莫耳比 1 : 1.5反應則可生成共頂點三立方烷型結構 (vertex-fused tricubane clusters) 之擴核產物 [Et4N]2[Te12M10(CO)24] (M = Mo, 4a; W, 4b)。若將化合物 2a-Mo(CO)3 及 2b 與過量之溫和氧化試劑 [Fe(C5H5)2][PF6] 反應則可生成共頂點三立方烷型結構，且有一 M‒M 金屬鍵生成之中性團簇物 [Te12M10(CO)24] (M = Mo, 5a; W, 5b)。將化合物 5a(5b) 及 3b 加入還原試劑Na/Ph2CO可逆反應回化合物4a(4b) 及 2b。此外，從電化學實驗結果觀察到此系列團簇物隨著氧化至後續產物，還原峰往陽極偏移之趨勢。由液態吸收光譜觀察到此系列化合物隨著氧化至後續產物，實驗光譜呈現紅移現象。2. E‒Fe-Hg-Cu 系統 (E = S, Se, Te) 系統之研究 將聚合物[{Cu(MeCN)2(dpy)}{BF4}]n (1) 與團簇物 [Et4N]2[{EFe3(CO)9}2Hg] (E = S, [Et4N]2[2a]; Se, [Et4N]2[2b]; Te, [Et4N]2[2c])以液態輔助研磨 (liquid-assisted grinding) 方式進行陰離子交換反應，可成功得到一維聚合物[{Cu(dpy)(MeCN)2}2{{TeFe3(CO)9}2Hg}]n (3) 、[{Cu(dpy)(MeCN)}2{{SFe3(CO)9}2Hg}]n (5) 和混合一維及二維骨幹之陰陽離子聚合物 [{Cu(dpy)(MeCN)2}{Cu(dpy)1.5(MeCN)}{{EFe3(CO)9}2Hg}]n (E = Se, 4-Se; Te, 4-Te)。且透過X-ray 結構解析得知一系列陰陽離子聚合物皆具有許多弱作用力存在於陽離子骨架和陰離子簇中，如 C‒H···π, C‒H···O氫鍵, 和 O···O 作用力。除此之外，由固態反射式紫外/可見光光譜測量的一系列聚合物的能階 (energy gap) 發現陰陽離子結合之聚合物能隙 (1.36‒1.55 eV) 遠低於起始物[{Cu(MeCN)2(dpy)}{BF4}]n 能隙 (2.46 eV)，進一步透過錠片電導率 (Electrical Conductivity) 探討此系列聚合物之導電特性，發現聚合物 4-Se， 4-Te 電導率 (1.26‒5.39×10-6 S∙cm–1) 遠低於起始物 1 (4.02×10-7 S∙cm–1)。然而，聚合物3, 4-Se, 4-Te 和 5之晶體顯示較錠片更低之電導率數值 (1.48‒5.34×10-7 S∙cm-1) 。配合晶體晶面解析 (crystal index) 探討聚合物電子傳遞之方向，發現聚合物 4-Se, 4-Te 晶體的最長邊與b軸重合，顯示聚合物 4-Se, 4-Te皆以1D/2D 的陽離子結構以及陽離子之間C‒H···π 作用力為橋梁進行電子傳遞。而聚合物 5 晶體的最長邊與a軸重合，顯示聚合物 5 應是沿著陰離子 [Et4N]2[2a] 和分子間 C-H…O 氫鍵弱作用力作為橋樑進行電子傳遞。這些弱作用力可以有效地促進電子傳輸，從而增強了此系列聚合物在固態下的穩定性和半導體行為。1. Te-M-CO system (M = Mo, W) systemA novel series of polynuclear tellurium-containing group 6 transition metal carbonyl clusters, the cage-like [Et4N]4[Te7Mo6(CO)20] (1), the basket-like [Et4N]4[Te6Mo6(CO)15] (2a-Mo(CO)3) and the bowl-like complex [Et4N]4[Te6W5(CO)12] (2b) can be synthesized from different ratios of Te powder, M(CO)6 (M = Mo, W) and Et4NBr in KOH/MeOH/MeCN solution. When complex 1 reacted with oxidizing reagent I2 at a molar ratio of 1: 1, a wheel-shaped structure [Et4N]2[Te8Mo6(CO)18] (6) can be synthesized. If complex 2b was treated with I2 at a molar ratio of 1: 1, a new W‒W metal bonded compound [Et4N]2[Te6W5(CO)12] (3b) was obtained. Further, when complexes 2a-Mo(CO)3 and 2b reacted with I2 at a molar ratio of 1: 1.5, the vertex-fused tricubane products [Et4N]2[Te12M10(CO)24] (M = Mo, 4a; W, 4b) can be generated. Importantly, a M‒M metal bonded neutral tricubic clusters [Te12M10(CO)24] (M = Mo, 5a; W, 5b) were produced upon the treatment of 2a-Mo(CO)3 and 2b with an excess amount of [Fe(C5H5)2][PF6]. On the contrary, compounds 5a(5b) and 3b can be reconverted back to compounds 4a(4b) and 2b by treating with reducing reagent Na/Ph2CO. In addition, the DPV study showed that the redox peaks of 4a(4b) and 5a(5b) were anodically shifted from those for 2a-Mo(CO)3 and 2b. Furthermore, the UV-vis spectra revealed that the absorption peaks were red-shifted as these clusters were more oxidized, and their electronic transition behaviors were further elucidated by time-dependent density functional theory (TDDFT). Finally, it was worthy to note that this series of tellurium-containing polynuclear group 6 transition metal (Mo, W) carbonyl clusters exhibited semiconducting behavior with low energy gaps (0.50‒1.10 eV) and good electrical conductivities (1.54‒3.54×10-7 S∙cm–1). The efficient electron transports of the synthesized complexes were further studied and discussed by the crystal packing.2. E‒Fe-Hg-Cu (E = S, Se, Te) polymers system A series of 1D and mixed 1D/2D Cu polymers, [{Cu(dpy)(MeCN)2}2{{TeFe3(CO)9}2Hg}]n (3), [{Cu(dpy)(MeCN)}2-{{SFe3(CO)9}2Hg}]n (5), and [{Cu(dpy)(MeCN)2}{Cu(dpy)1.5(MeCN)}-{{EFe3(CO)9}2Hg}]n (E = Se , 4-Se; Te, 4-Te) can be successfully obtained from liquid-assisted grinding of polymer [{Cu(MeCN)2(dpy)}{BF4}]n (1) with anionic clusters [Et4N]2[{EFe3(CO)9}2Hg] (E = S, [Et4N]2[2a]; Se, [Et4N]2[2b]; Te, [Et4N]2[2c]). X-ray analysis indicated that numbers of secondary interactions, such as C‒H···π, C‒H···O(carbonyl) hydrogen bond, and O···O(carbonyl) interactions, existed within the Cu-dipyridyl frameworks and encapsulated clusters. In addition, these anionic cluster-incorporated Cu polymers were found to possess low energy gaps (1.36‒1.55 eV) and surprising electrical conductivities (1.92‒5.28 ×10-6 S∙cm-1), which were significantly lower than polymer 1 (2.46 eV and 4.02 ×10-7 S∙cm-1). Besides, the single-crystal electrical conductivity of polymers 3, 4-Se, 4-Te, and 5 were also examined and lower values (1.54‒5.02 ×10-7 S∙cm-1) were found in each case in comparison to those measured by the pressed pellet samples. Further, the longest dimension of the crystal 4 or 5 has coincided with the crystallographic b or a axis, which were correlated to the direction of 1D/2D cation framework and C‒H···π interactions or cross-linked 2a and C‒H···O interactions, respectively. These weak interactions can effectively facilitate the electron transports, which enhanced the stability and semiconducting behaviors in the solid state.