含主族元素 (Se、Te) 與過渡金屬 (Cr、Mo、W 、 Mn) 團簇化合物之合成與反應性及電化學研究

Abstract

[1] 碲(Te)-鉻(Cr)-鉬(Mo)、鎢(W)系統的研究 將 [Te2Cr3(CO)10]2− (1) 與 4 當量 Mo(CO)6 於 Acetone 中加熱迴流，不同的反應時間可得到不同結果：加熱反應一天可得已知之開放型結構 [Te2Mo4(CO)18]2− (2)；反應時間延長至兩天不但可得含 2 個 hydride 之主結構為四面體的 [H2Te2Mo4(CO)12]2− (3)，亦可獲得含 2 個 hydride 之主結構為八面體的擴核新結構 [H2Te3Mo5(CO)14]2− (4)；更將 Te-Cr-Mo 系統拓展至 Te-Cr-W 系統，提高反應溫度與時間可得到已知開放型結構 [Te2W4(CO)18]2− (7) 及另外兩個新的化合物類似於 Te-Cr-Mo 系統之具有 2 個 hydride結構 [H2Te2W4(CO)12]2− (7) 與 [H2Te3W5(CO)14]2− (8)。另外，我們也利用 DFT 理論計算來佐證推測之反應路徑。

[2] 碲(Se)-鉻(Cr)系統的研究 成功得到新的開放型橋接結構 [Se{Cr(CO)5}3]2− (1)，與有機試劑 CF3SO3Me 反應可得 [MeSe{Cr(CO)5}3]− (2)，與異核金屬試劑 HgCl2 反應可得以 Hg 橋接之雙聚合物 [HgSe2{Cr(CO)5}4]2− (3)；在鹼性 MeOH 或 EtOH 中加熱反應可分別得已知 [Se2Cr3(CO)10]2− (4) 及新型有機金屬團簇化合物 [Me2Se2Cr2(CO)7]2− (5)。嘗試與小分子氣體在不同條件下進行反應，可得到多種新穎之自組裝性產物，分別為 [Se3{Cr(CO)5}4]2− (6)、[Se2{Cr(CO)5}3]2− (7) 以及 [Se2Cr4(CO)18]2− (8)；並藉 DFT 理論計算佐證產物生成的可能原因及推測之反應機制。

[3] 硒(Se)-鉻(Cr)-錳(Mn)系統的研究 將 [Se2Cr3(CO)10]2− 與 1.8 當量 Mn(CO)5Br 於 Acetone 中反應，可得到兩個史無前例之 Mn 原子引入 Se-Cr 羰基化合物之結構 [Me2CSe2{Mn(CO)4}{Cr(CO)5}2]− (1) 與 [Se2Mn3(CO)10{Cr(CO)5}2]2− (2)，將化合物 2 於 MeCN 中通入 CO 氣體下加熱反應，則會得到 [Se2Mn3(CO)9]2− (3)。針對[Se2Cr3(CO)10]2−、化合物 2 及化合物 3 進行磁性分析。此外，更對化合物 2 及 3 進行電化學分析，藉由 DFT 理論計算輔佐更深入探討其氧化還原過程。

[4] 碲(Te)-鉻(Cr)-錳(Mn)系統的研究 本研究室成功得到文獻中罕見具有 Cr-Mn金屬鍵之封閉型雙三角錐結構 [Te2CrMn2(CO)9]2- (2)，以及文獻上第一個由主族元素及 Cr-Mn 鍵生成之四角錐結構化合物 [Te2CrMn2(CO)10]2- (3)，兩者可藉由 CO 氣體的通入與加熱脫除進行可逆反應。對兩者作磁性及電化學分析，發現兩者具有電化學之轉換關係，藉由固定電位方法找出開關電位之正確位置，並藉 DFT 理論計算的輔佐，推導兩者在化學上與電化學上之轉變的反應機制。

[1] Te-Cr-Mo, W system The reaction of [Te2Cr3(CO)10]2- (1) and 4 eq Mo(CO)6 gave various complexes under different reaction conditions. A known open-cluster [Te2Mo4(CO)18]2− (2) can be obtained in refluxing acetone for 1 day, and a hydrido-tetrahedral cluster [H2Te2Mo4(CO)12]2− (3) and a novel expanding hydrido-octahedral cluster [H2Te3Mo5(CO)14]2− (4) can be obtained in refluxing acetone solution for 2 days. Moreover, we explored the related Te-Cr-W system. With higher temperatures and prolonged time, two analogous hydrido-clusters [H2Te2W4(CO)12]2− (7) and [H2Te3W5(CO)14]2− (8) were obtained. These reactions were further investigated by molecular orbital calculations at the B3LYP level of the density functional theory.

[2] Se-Cr system A new open chromium-containing carbonyl selenide [Se{Cr(CO)5}3]2− (1) was obtained from the reaction of Se powder with Cr(CO)6 in a molar ratio of 2:3 in basic methanol. The reaction of 1 with CF3SO3Me produced [MeSe{Cr(CO)5}3]− (2), while the reaction with HgCl2 afforeded the dimeric Hg-bridged metal cluster [HgSe2{Cr(CO)5}4]2− (3). When 1 was treated with NaOH/ROH (R= Me, Et) solution, the known product [Se2Cr3(CO)10]2− (4) and a butterfly complex [Me2Se2Cr2(CO)7]2− (5) were obtained, respectively. Moreover, the stability of 1 and its related reactions were investigated by molecular orbital calculations at the B3LYP level of the density functional theory.

[3] Se-Cr-Mn system We have discovered two unprecedented manganese-incorporated selenium-chromium carbonyl complexes from the reaction of [Et4N]2[Se2Cr3(CO)10] with Mn(CO)5Br in acetone. One is a novel complex [Me2CSe2{Mn(CO)4}{Cr(CO)5}2]− (1) which presumably via C=O activation of acetone and the other is a cluster-expanded structure [Se2Mn3(CO)10{Cr(CO)5}2]2− (2) which can readily convert to [Se2Mn3(CO)9]2─ upon heating and bubbled with CO. In addition, the magnetic properties of [Se2Cr3(CO)10]2−, 2 and 3 were investigated by the SQUID measurement, and the electrochemical properties of 2 and 3 were studied by CV and DPV techniques. Moreover, the electrochemistry were further examined by molecular orbital calculations at the B3LYP level of the density functional theory.

[4] Te-Cr-Mn system [Te2CrMn2(CO)9]2- (2) and [Te2CrMn2(CO)10]2- (3) that containing rare Cr-Mn bond were successfully synthesized. They can be converted to each other by bubbling CO gas or heating. There chemical and electrochemical redox reactions were studied which were further elucidated by molecular orbital calculations at the B3LYP level of the density functional theory.