萘啶-含氮雜環碳烯金屬錯合物之合成及其催化活性探討

Metal Complexes with a Naphthyridine-Based N-Heterocyclic Carbene (NHC) Lignad: Synthesis and Catalytic Activities

黃筱晴(Hsiao-Ching Huang)

指導教授 ： 劉緒宗

國立臺灣大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.01532

摘要

本論文探討萘啶-含氮雜環碳烯過渡金屬錯合物的合成、結構解析與催化應用。以新發展出的萘啶-含氮雜環碳烯做為輔助配位基，利用銀金屬將配體轉移至銠、銥及鈀金屬上，而得到相對應之錯合物。
將萘啶-含氮雜環碳烯配體，與AgNO3及K2CO3反應可得雙碳烯銀金屬錯合物。令其與[Rh(COD)Cl]2或[Ir(COD)Cl]2反應，能製備出碳烯配位之銠(I)和銥(I)碳烯金屬錯合物。以X光單晶繞射分析銠錯合物，揭示其金屬中心有環辛二烯及碳烯的配位，且金屬中心呈平面四邊形的結構。再藉四氟硼酸銀移除氯離子，使萘啶配位至金屬上，形成萘啶-含氮雜環碳烯雙配位之離子性錯合物，並以核磁共振技術及質譜確認其結構。使用銀錯合物做為轉移試劑，與四氟硼酸銀及[Pd(C3H5)Cl]2進行一鍋化反應，可製備離子性之鈀金屬錯合物。藉X-ray單晶繞射的協助，確認鈀金屬上的亞甲基以η3的型式配位至金屬上，且萘啶及碳烯皆有參與配位，金屬中心呈平面四邊形的結構。
萘啶-含氮雜環碳烯鈀錯合物可做為氫轉移反應的催化劑，以甲酸做為氫來源，能選擇性地還原α, β-不飽和烯酮的C=C雙鍵。相較於製備出的銠和銥金屬錯合物及其他鈀錯合物展現較好的選擇性與活性。藉由此催化，可將α, β-不飽和羰基、酯類、醯胺基、酸類轉變為相對應的飽和酮、酯、醯胺和酸。

關鍵字

萘啶 ； 含氮雜環碳烯

並列摘要

In this work, we explored the syntheses, characterization and catalytic activity of metal complexes containing a naphthyridine-based N-heterocyclic carbene ligand. The desired rhodium(I), iridium(I) and palladium(II) complexes were obtained via a known carbene transfer method. The reaction of naphthyridine-based NHC ligand 6, silver nitrate and potassium carbonate afforded the silver bis-carbene complex 7. Upon the reaction between the silver NHC complex with [Rh(COD)Cl]2 or [Ir(COD)Cl]2, the carbene fragment readily transferred from silver to rhodium and iridium center, providing the Rh(I) and Ir(I) carbene complex. As revealed in X-ray crystallography, Rh(I) carbene complex 8 adopted a square-planar geometry with the coordination of cyclooctadiene moiety. The rhodium and iridium carbene complex 8 and 9 can be converted to the corresponding ionic ones 10 and 11 by using silver tetrafluoroborate to remove chloride. The palladium(II) complexes 12 was prepared through the reaction of silver complex 7, [Pd(C3H5)Cl]2 and silver tetrafluoroborate. Its structure was confirmed by X-ray crystal structural analysis to illustrate the coordination of a η3-allyl fragment and the square planar geometry around the metal center. The palladium(II) complex 12 acted as an effective catalyst toward hydrogen transfer reaction. The C=C of α, β-unsaturated carbonyl substrates can be selectively reduced to yield saturated carbonyl compounds with formic acid as the proton source. Compared to the Rh(I) and Ir(I) complexes as well as other palladium complexes, it exhibited better catalytic activity and selectivity. With this method, α, β-unsaturated ketones, esters, amides and acids can be selectively hydrogenated to the corresponding saturated compound.

並列關鍵字

Naphthyridine ； N-heterocyclic carbene

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