含唑-萘啶配基之金屬錯合物的合成及其催化研究

Abstract

本論文以1,8-萘啶為主體，分別在2號位與7號位修飾吡唑與甲基或羧基而得 2-(1H-pyrazol-1-yl)-7-methyl-1,8-naphthyridine (4)與2-(1H-pyrazol-1-yl)-7- carboxyl-1,8-naphthyridine (5)，以這些配位基與金屬化合物進行配位化學反應，合成出釕金屬半夾層錯合物[(4)(h6-benzene)RuCl2] (Ru1), [(5)(h6-benzene)RuCl2] (Ru2)及[(5)(h6- p-cymene)RuCl2] (Ru3)；與銠金屬錯合物[(5)Rh2(m-OAc)3] (Rh1)。這些錯合物可由NMR、ESI-Mass鑑定其結構，其中Ru2、Ru3更進一步以單晶解析確認。 其中錯合物Ru2具有不錯的水溶性，利用此一性質在甲酸水溶液中進行氫轉移反應。利用不同酸鹼值對反應的影響，同時比較Ru1、Ru3及其他不同釕金屬錯合物與Ru2對於此反應的差異，探討Ru2上自由酸根對反應的影響。此研究亦對於一系列的苯甲醛進行氫轉移還原的實驗，並探討取代基對於反應的影響。

In this work, 2- and 7-substituted 1,8-naphthyridinyl based ligands, 2-(1H-pyrazol-1-yl)-7-methyl-1,8-naphthyridine (4) and 2-(1H-pyrazol-1-yl)-7- carboxyl-1,8-naphthyridine (5) were synthesized. Complexes containing these ligands such as [(4)(h6-benzene)RuCl2] (Ru1), [(5)(h6-benzene)RuCl2] (Ru2), [(5)(h6-p-cymene)RuCl2] (Ru3) and [(5)Rh2(m-OAc)3] (Rh1) were prepared. The resulting complexes have been characterized by spectroscopic methods. Structures of both Ru2 and Ru3 were further confirmed by X-ray crystallography. The carboxyl group on Ru2 enhances its solubility in water. Thus, we investigated its catalytic activity in aqueous medium. With the use of formate/formic acid as the hydrogen source, we studied the transfer hydrogenation of aldehydes via these ruthenium complexes. Various parameters affecting the reactions and comparison of activities of metal complexes were revealed. Hydrogen-transfer reduction of a series of carbonyl compounds typically benzaldehydes was investigated and substituent effect on substrates was discussed.