混合過渡金屬 (鉻、鐵) 之十五族 (銻、鉍) 錯合物與含十六族 (硫、硒、碲) 三鐵羰基汞銅陰陽離子聚合物之合成與其反應性及物性之探討

Abstract

E‒Cr‒Fe 系統 (E = Sb, Bi)

過去已發表之平面化合物 [E{Cr(CO)5}3]‒ (E = Sb, 1; Bi, 2) 皆具有缺電子之不飽和性質，因此本研究進一步針對其路易士酸性、與親核試劑反應的差異進行探討。研究結果顯示，化合物 1 能與極弱親核試劑水 (H2O) 反應得路易士加成物 [(HO)Sb{Cr(CO)5}3]2‒ (1-OH)，但化合物 2 則無反應。有趣的是，由高解析 X-ray 電子能譜 (HR-XPS) 得知化合物 1 之中心 Sb 原子氧化態為 0 價。當 2 與 [HFe(CO)4]‒ 反應時，可得四面體化合物 [{Fe(CO)4}Bi{Cr(CO)5}3]3‒ (2-Fe)。進一步以 2-Fe 與 [FeCp2][PF6] 反應會經過一中間物 [Bi{Cr(CO)5}2{Fe(CO)4}]‒ (3) 而後斷裂重組生成穩定產物 [{Cr(CO)5}2Bi2{Fe(CO)3}3]2‒ (4)。另一方面，化合物 1 與 [HFe(CO)4]‒ 反應則生成 [(H)Sb{Cr(CO)5}2{Fe(CO)4}]2‒ (1-Fe) 與 [(H)Sb{Cr(CO)5}3]2‒ (1-H) 之混合物。此外，當 1-Fe 與過量 HBF4 於室溫下反應，可得耦合 (coupling) 產物 [FSb2{Cr(CO)5}3{Fe(CO)4}2]‒ (6)。有趣的是，若將 1-Fe 與 1 當量 [CPh3][BF4] 於 ‒30 oC 下反應可得 [Sb2{Cr(CO)5}4{Fe(CO)4}2]2‒ (7)。若 1-Fe 與 [CPh3][BF4] 於室溫下反應，並提高 [CPh3][BF4] 之當量數，則可得到 6 與極少量 [(HO)Sb2{Cr(CO)5}3{Fe(CO)4}2]‒ (8)。推測化合物 7 為中間物，可進一步生成 F 或 OH 取代之化合物 6 與 8。最後，本研究藉由電化學及 density functional theory (DFT) 理論計算輔佐，探討此系列反應之機制及氧化還原行為。

E‒Fe-Hg-Cu 系統 (E = S, Se)

將 [PPh]4[SeFe3(CO)9] 及 Hg(OAc)2 以當量比 1: 2 於 −30 oC MeCN 中進行反應，可得 Hg 原子橋接兩個 SeFe3 團簇物之化合物 [PPh4]2[{(μ3-Se)Fe3(CO)9}Hg{(μ4-Se)Fe3(CO)9}] ([PPh4]2[2])。[PPh4]2[2] 進一步與過去已發表之銅一維聚合物 [{Cu(MeCN)2(dpy)}{BF4}]n (1) 利用液態輔助研磨 (liquid-assisted grinding) 方式進行陰離子交換反應，可形成團簇物 2 之結構異構物嵌入含混合一維及二維銅陽離子的聚合物 [{Cu(dpy)(MeCN)2}{Cu(dpy)1.5(MeCN)}{{(3-Se)Fe3(CO)9}2Hg}]n (4)。若以 [Et4N]2[{(3-S)Fe3(CO)9}2Hg] 與聚合物 1 利用研磨進行陰離子交換反應後，結晶可得含硫−銅進一步鍵結之配位聚合物 [{Cu(dpy)(MeCN)}2{(4-S)Fe3(CO)9}2Hg]n (3')。此外，進一步透過高解析 X-ray 電子能譜 (HR-XPS) 及 X-ray 吸收近邊緣結構光譜 (XANES)，探討 EFe3Hg-Cu (E = S, Se, Te) 系列聚合物之銅原子氧化態。並由晶體固態堆疊圖發現，此系列聚合物皆具有分子間 C‒H…O 氫鍵，進一步證實電子傳遞之現象。

E‒Cr‒Fe system (E = Sb, Bi)

We focus on the difference of Lewis acidity and reactivity between the reported 4-center, 6-conjugated unsaturated trigonal-planar complex, [E{Cr(CO)5}3]– (E = Sb, 1; Bi, 2). When 1 was reacted with weak nucleophile H2O, Lewis adduct [(HO)Sb{Cr(CO)5}3]2‒ (1-OH) was formed. However, 2 was unreacted with H2O, showing the greater Lewis acidity of 1 than that of 2, which was further supported by DPV studies. Since the oxidation state of Bi in 2 was previously determined to be +3, the oxidation state of Sb in 1 was assigned in 0 by X-ray photoelectron spectroscopy (XPS). The strong Lewis acidity of 1 may be attributed to its electronic unsaturated character, even if the Sb atom was electron-rich. In addition, when 2 was treated with [HFe(CO)4]–, the tetrahedral complex [{Fe(CO)4}Bi{Cr(CO)5}3]3– (2-Fe) was obtained which can further react with [FeCp2][PF6] to produce [{Cr(CO)5}2Bi2{Fe(CO)3}3]2‒ (4) via a mixrd Cr–Fe trigonal-planar intermediate [Bi{Cr(CO)5}2{Fe(CO)4}]– (3). On the other hand, similar reaction of 1 with [HFe(CO)4]– led to the formation of a mixture of [(H)Sb{Cr(CO)5}2{Fe(CO)4}]2‒ (1-Fe) and [(H)Sb{Cr(CO)5}3]2‒ (1-H). This distinct reaction pattern was deduced to the different electronegativity and atomic size between the Sb and Bi atoms. Interestingly, the treatment of the 1-Fe with excess HBF4 at room temperature afforded the coupling product [FSb2{Cr(CO)5}3{Fe(CO)4}2]‒ (6). While the deprotonation of 1-Fe with 1 equivalent of [CPh3][BF4] at ‒30 oC gave rise to the complex [Sb2{Cr(CO)5}4{Fe(CO)4}2]2‒ (7), the treatment with 1.5 equivalents of [CPh3][BF4] resulted in the formation of a mixture of [(HO)Sb2{Cr(CO)5}3{Fe(CO)4}2]‒ (8) and 6. Finally, the reaction mechanism and electronic structures of 1 and 2 were elucidated with the aid of density functional theory (DFT) calculations.

E‒Fe-Hg-Cu system (E = S, Se)

When [PPh4]2[SeFe3(CO)9] was treated with 2 equiv of Hg(OAc)2 in MeCN solution at –30 oC, the Hg-bridged di-SeFe3 cluster [PPh4]2[{(μ3-Se)Fe3(CO)9}Hg{(μ4-Se)Fe3(CO)9}] ([PPh4][2]) was obtained. Furthermore, the reaction of [PPh4][2] with [{Cu(MeCN)2(dpy)}{BF4}]n (1) via liquid-assisted grinding (LAG) led to the formation of [{Cu(dpy)(MeCN)2}{Cu(dpy)1.5(MeCN)}{{(3-Se)Fe3(CO)9}2Hg}]n (4). Similar reaction of [Et4N]2[{SFe3(CO)9}2Hg] with 1 via LAG produced structural isomers [{Cu(dpy)(MeCN)}2{(4-S)Fe3(CO)9}2Hg]n (3 and 3'), as evidenced by XRD and PXRD analyses. Interestingly, the solid-state packings showed that the unexpected non-classical C‒H…O (carbonyl) hydrogen bonds existed in the frameworks of the series of EFe3Hg-Cu (E = S, Se, Te) polymers, which can be regarded to facilitate the electron transport. The intriguing structure-property relationships were demonstrated by the significant change in the oxidation state of Cu atom by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure spectroscopy (XANES).