雙鈷金屬錯合物的合成與其催化應用

A dinuclear cobalt(II) complex: Synthesis and Catalytic Applications

王泰霖(Tai-Lin Wang)

指導教授 ： 劉緒宗

國立臺灣大學/理學院/化學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201701118

摘要

在本篇論文探討多牙氮配位基5-phenyl-2,8-bis(6’-bipyridinyl)-1,9,10-anthyridine (pbbpa)與鈷金屬形成了一個配位基10號位被甲醇分子行1, 4加成(1, 4-addition)的雙鈷金屬錯合物。此錯合物作為催化劑來探討3,5-二-叔丁基-鄰苯二酚的氧化以及苄基位(benzylic site)的氧化，同時利用其特別的物性做催化劑的回收。
在甲醇下，pbbpa與Co(OAc)2形成雙鈷化合物。此錯合物經由紅外線光譜、紫外線光譜、MALDI-TOF質譜和X光單晶繞射等方式鑑定。得知其為具有多種配位模式的乙酸根配基(單配位、鉗合配位及橋接配位)的六配位雙鈷金屬錯合物。
在空氣中，雙鈷金屬可活化3,5-二-叔丁基-鄰苯二酚，使其變成3,5-二-叔丁基-鄰苯二醌，且在pH值為8時，此雙鈷金屬錯合物與其他含有三聯吡啶或鄰二氮菲單核鈷錯合物相比下，有著催化上的優勢，展現了雙鈷金屬的協同效應(synergistic effect)。另外，以TBHP為氧化劑，使其能將許多含有苄基位的化合物氧化成酮基，也利用其極易溶於甲醇且完全不溶於乙醚和乙酸乙酯的特性，發展了一套回收催化劑的策略，在四次的回收再反應中，可發現不失其活性，此一結果顛覆了傳統上勻相催化劑不能做回收的刻板印象。

關鍵字

雙鈷金屬錯合物

並列摘要

Coordination of 5-phenyl-2,8-bis(6’-bipyridinyl)-1,9,10-anthyridine toward Co(OAc)2 •4H2O resulted in the formation of a dinuclear cobalt complex, in which the C-10 position of the ligand was attacked by a methanol molecule.
This complex was characterized by MALDI, IR, UV and X-ray crystallography. We recognized that two metal centers were adopted in the core of each terpyridine moiety of the ligand and three acetate molecules act as bridging, terminal and η2-chelating ligand, respectively.
To show the practical applications of this complex, some experiments need to be designed to reveal its catalytic potential. In our first step, we found that our complex with TBHP as the oxidant could functionalize the benzylic C-H bond to alcohol, ketone and carboxylic acid. Surprisingly, by manipulating the subtle solubility of the complex in ethyl ether and methanol, the complex could be reused after the reaction without losing it’s catalytic activity. At second part, the aerobic oxidation reaction was developed by using 3,5-di-tert-butylcatechol as the starting material and the kinetic plots show that under slightly basic condition, the dimetallic effect plays a important role in raising the reaction rate.

並列關鍵字

dicobalt complex

參考文獻

(47)楊舒庭 國立台灣大學化學系碩士論文-多牙氮配位基及雙金屬鈀錯合物的合成與其催化應用, 2017.

(48)黃大維 國立台灣大學化學系博士論文-多牙配位基環鈀化錯合物與雙金屬錯合物之合成、性質及催化活性, 2016.

(31)Deacon, G. B.; Phillips, R. J. Coord. Chem. Rev. 1980, 33, 227-250

(4)Tokmic, K.; Fout, A. R. J. Am. Chem. Soc. 2016, 138, 13700−13705.

(10)H. J. Lu, Subbarayan V., J. G. Tao and X. P. Zhen Organometallics 2010, 29 (2), 389–393