萘啶與吡啶羧酸衍生物配位基釕金屬錯合物之合成與催化應用

Synthesis and Catalytic Application of Ruthenium Complexes with Naphthyridine and Pyridine Carboxylic Acid Derivatives Ligands

許晏賓(Yen-Pin Hsu)

指導教授 ： 劉緒宗

國立臺灣大學/理學院/化學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202100467

摘要

本篇研究以萘啶羧酸衍生物配位基N-(pyridin-2-ylmethyl)-1,8-naphthyridine-2-carboxamide(L1)、1,8-naphthyridine-2-carboxamide(L2)、1,8-naphthyridine-2-carboxylic acid (L3) 及吡啶羧酸衍生物配位基N-(pyridin-2-ylmethyl)picolinamide (L4)、 picolinamide (L5)，與picolinic acid (L6)，與金屬前驅物RuHCl(CO)(PPh3)3及〔Ru(cymene)Cl2〕2分別進行錯合反應得到錯合物，包含雙牙配位的〔Ru(L1-3,5-6)H(CO)(PPh3)2〕(Ru1-3、7-8)、〔Ru(L2-3,5-6)(cymene)Cl〕(Ru4-5、9-10)，及三牙配位的〔Ru(L1)(CO)(PPh3)Cl〕(Ru6)。
為了探討不同羧酸衍生物的配位基效應。首先進行苯胺與苯甲醇的N-烷基化催化反應，以叔丁醇鉀作為鹼，於無溶劑且氮氣環境加熱120°C進行。發現〔Ru(L)H(CO)(PPh3)2〕系列反應表現優於〔Ru(L)(cymene)Cl〕系列，且選擇性較佳。錯合物Ru1與Ru6，得到相似的反應結果，顯示錯合物Ru1原先之氫負離子對反應影響甚微。此外，錯合物Ru1之配位基L1其側基(Pendant)吡啶，可與中心金屬配位，穩定金屬中間體；也可能藉由氫鍵作用力引入反應物，促使反應順利進行。錯合物Ru2、7、4、9的選擇性優於對應之錯合物Ru3、8、5、10，是由於醯胺陰離子比羧酸根有更好的電子貢獻能力。最後，萘啶錯合物與對應之吡啶錯合物的反應性及選擇性相近，說明反應可能是藉由內層的反應機制進行。
於2-硝基苯胺與1,2-二醇環化加成催化反應，以碳酸銫作為鹼，以對二甲苯作為溶劑，於氮氣環境加熱120°C進行。錯合物Ru1、Ru6，得到相似且最佳的反應結果，再次顯示錯合物Ru1原先之氫負離子對反應影響甚微。而使用錯合物錯合物Ru2、Ru3時，僅得到微量產物，說明配位基L1其側基(Pendant)吡啶於此催化反應，扮演重要的穩定角色。若使用配位基L4、L7與金屬前驅物RuHCl(CO)(PPh3)3進行反應時，僅能得到少量產物，推測萘啶額外的吡啶可透過氫鍵作用力，引入雙官能基的雙醇反應物。〔Ru(L)(cymene)Cl〕系列，在此催化反應無法得到對應產物。

關鍵字

羧酸衍生物配位基 ； 吡啶羧酸衍生物配位基 ； 釕金屬錯合物 ； N-烷基化反應 ； 2-硝基苯胺 與 1,2-二醇環化加成反

並列摘要

Three different naphthyridine carboxylic acid derivative ligands, 1 N-(pyridin-2-ylmethyl)-1,8-naphthyridine-2-carboxamide (L1)、1,8-naphthyridine-2-carboxamide (L2)、 1,8-naphthyridine-2-carboxylic acid (L3), and two pyridine carboxylic acid derivative ligands, N-(pyridin-2-ylmethyl)picolinamide (L4) 、picolinamide (L5) ,are synthesized. Complexation of [RuHCl(CO)(PPh3)3] and [Ru(cymene)Cl2]2，with L1-5 and picolinic acid (L6), provided the corresponding complexes, including bidentate complexes [Ru(L1-3,5-6)H(CO)(PPh3)2] (Ru1-3、7-8)、[Ru(L2-3,5-6)(cymene)Cl] (Ru4-5、9-10) and tridentate complex [Ru(L1)(CO)(PPh3)Cl] (Ru6).
In order to investigate the ligand effect, these complexes are applied to the catalytic N-alkylation of aniline with benzyl alcohol using potassium tert-butoxide as base under neat and nitrogen atmosphere at 120°C. The series of [Ru(L)H(CO)(PPh3)2] exhibit better catalytic activity and selectivity than the series of [Ru(L)(cymene)Cl]. The catalytic activity and selectivity of Complex Ru1 and Ru6 are similar, and the result show the influence of the hydride on the complex Ru1 is not apparent. Moreover, the pendant pyridine of ligand L1 can coordinate to the metal center during the reaction to stabilize the metal intermediate, and can also attract the reactant to the metal center using hydrogen bonding interaction. Complexes Ru2、Ru7、Ru4、Ru9 display higher selectivity than those of complexes Ru3、Ru8、Ru5、Ru10. The results are attributed to stronger electron donation of amido moiety than carboxylate moiety. In addition, the complexes using naphthyridine carboxylic acid derivative as ligand show similar catalytic activity and selectivity with those complexes with pyridine ligand. The observation implies the reaction might be inner sphere mechanism.
In the reaction of cycloaddition of 2-nitroaniline and 1,2-diol uses cesium carbonate as base under nitrogen atmosphere in para-xylene solvent at 120°C. It turns out that complexes Ru1 and Ru6 show the similar result and catalytic activity, implies the influence of the hydride on the complex Ru1 is negligible on the catalytic reaction. Using complex Ru2 and Ru3 as catalyst in this catalytic reaction, the yield is very low. The big different results between complex Ru1 and complex Ru2、 Ru3 show that pendant pyridine of ligand L1 plays an important role in this reaction which could coordinate to the metal center and stabilize the metal intermediate. However, using ligand L4、L7 and metal precursor [Ru(L)H(CO)(PPh3)2] as catalyst, giving low yield. The observation implies the additional pyridine on the naphthyridine ligand might attract bifunctional 1,2-diol reactant to the metal center with hydrogen bonding interaction. The series of [Ru(L)(cymene)Cl] are not effective catalysts in the cycloaddition reaction.

並列關鍵字

Naphthyridine Carboxylic Acid Derivatives Ligands ； Pyridine Carboxylic Acid Derivatives Ligands ； Ruthenium Complexes ； N-alkylation ； Cycloaddition of 2-nitroaniline and 1,2-diol

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