多吡啶氮異環碳烯釕錯合物之合成與性質研究

Synthesis and characterization of Polypyrodyl N-Heterocyclic Carbene based Ruthenium complexs

劉仲晨(Chung-Chen Liu)

指導教授 ： 王文竹

淡江大學/理學院/化學學系碩士班/碩士(2012年)

https://doi.org/10.6846/TKU.2012.01336

摘要

本論文合成出一系列含氮異環碳烯(N-Heterocyclic Carbene, NHC)的多吡啶配位子，分別為L1(L1=6-mimbp)、L2(L2=6-mbzimbp)以及L3(L3=6-mtimbp)並與分別與RuIIICl3以及RuIII(tpy)Cl3反應，得到homoleptic釕錯合物1(1 =[Ru(L1)2](PF6)2)、2(2 = [Ru(L2)2](PF6)2)、3(3 = [Ru(L3)2](PF6)2)，以及heteroleptic釕錯合物4(4 = [Ru(L1)(tpy)](PF6)2)、5(5 = [Ru(L2)(tpy)](PF6)2)、6(6 =[Ru(L3)(tpy)](PF6)2)。以上化合物經由核磁共振光譜與質譜鑑定，並透過x-ray單晶繞射探討錯合物的幾何結構，以循環伏安法探討錯合物的電化學性質，利用吸收及放射光譜討論配位子及錯合物的光物理性質。

從X-ray的實驗結果顯示，錯合物1、2、4在幾何結構上，皆為扭曲的正八面體，近似於Ru(tpy)2以及其他文獻中以NHC釕錯合物之結構，不過錯合物1、2、4中的Ru-Carbene的鍵長最短可到1.988 (5)A。電化學實驗中，錯合物1的氧化電位為1.23 V ，判定為二價釕至三價釕的氧化，還原電位為-1.27 V及-1.54 V，分別判定為聯吡啶第一個電子及第二個電子的還原。釕錯合物的吸收光譜中，配位子π→π*躍遷發生在250 nm及300 nm，MLCT發生在450-470 nm範圍內。

放射光譜中，釕錯合物的3MLCT放光波長位在590-628 nm範圍內，其放光量子產率最高達0.0037，最低為0.00009，錯合物1-3的3MLCT生命期分別為90 ns，25 ns以及110 ns，顯示錯合物1-3的結構雖然與Ru(tpy)2¬相似，可是由於NHC上推電子能力的貢獻，擴大3MLCT及3MC的能量差，因此提升了放光效率以及激發態的生命期。

關鍵字

氮異環碳烯 ； 推電子能力 ； 釕 ； 聯吡啶

並列摘要

A series of New type Polypyridyl-N-Heterocyclic Carbene ligands, L1(L1=6-mimbp) 、L2(L2=6-mbzimbp)、L3(L3=6-mtimbp) and their Ruthenium complexes 1(1 =[Ru(L1)2](PF6)2)、2(2 = [Ru(L2)2](PF6)2)、3(3 = [Ru(L3)2](PF6)2)、4(4 = [Ru(L1)(tpy)](PF6)2)、5(5 = [Ru(L2)(tpy)](PF6)2)、6(6 =[Ru(L3)(tpy)](PF6)2) were synthesized and characterized by NMR and Mass. Through single crystal X-ray diffraction experiments, we confirmed all this type of Ruthenium complexs exhibit distorted octahedral structure, and the Ruthenium-carbene bond lengths were shortest in all other pyridyl type NHC Ruthenium complex. The electrochemical experimental data reveal that the imidazole NHC ligand contain good σ-donation and desatblized the HOMO energy level , benzimidazole NHC ligand contain good π-acception so stabilized HOMO energy level . In electron absorption spectra of complex 1-6, two strong absorption peak in UV were assigned as π→π* transition, absorption appeared around 450 nm to 470 nm were assigned as MLCT. In electronic emission spectra，emission peak near around were assigned as 3MLCT, by measuring the quantum yield and lifetime, the experiment results indicate that the NHC ligand could expand the energy gap between 3MC and 3MLCT so increase the emission quantum yield and lifetime of 3MLCT.

並列關鍵字

N-heterocyclic carbene ； σ-donation ； Ruthenium ； bipyridine

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