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  • 學位論文

萘啶配基之雙金屬錯合物的合成、性質與催化活性

Synthesis, Properties and Catalytic Activity of Dimetallic Complexes with Anthyridine-based Ligands

指導教授 : 劉緒宗

摘要


在本篇論文中,主要是合成以1,9,10-anthyridine為骨架之一系列不同取代的含氮多芽配體 (5a~5k),並與不同過渡金屬 (鈀、銠、銅、鎳)進行配位探討,更將所形成的金屬錯合物應用於多種催化反應。 於室溫下配位基5a、5b可與Pd(OAc)2反應生成環鈀化金屬錯合物[(5a)PdBr- (H2O)] (6a)與[(5b)2Pd2(OAc)2] (6b),進一步與三苯基膦配位,可形成結構穩定之二聚物 {[(5a)2Pd2(PPh3)2]Br2} (7a)和{[(5b)2Pd2(PPh3)2] } (7b),添加硫或一價金錯合物可使膦鈀鍵結斷裂變回6a與6b;藉由單晶結構得知,反式影響使碳原子對位的氮鈀鍵較長。由於與鈀金屬配位之碳原子為強電子予體,在催化應用上先以Suzuki-Miyaura 耦合反應測試其催化活性,發現芳香氯化物於水相系統中有良好的反應性;另外,於碳硼鍵的耦合反應,則展現了優異之催化能力,且具有理想的官能基容忍度。 第二部分則以配體 (5a,5c,5d,5e)與Rh2(OAc)4配位,生成含金屬-金屬鍵結之環銠化雙金屬錯合物 [Rh2(OAc)3(metalated-5a, 5c, 5d, 5e)] (8a, 8c, 8d, 8e),以1H- NMR、13C-NMR及X光單晶繞射結果可證實其碳氫鍵活化發生在軸位向。欲探討碳銠鍵結的性質,嘗試添加六氟磷酸銨可將其打斷變為 [Rh2(OAc)3(5e)][PF6] (9e)。另外,三苯基膦可取代8d、8e錯合物上主配體鄰位的醋酸根,以磷與碳原子架橋配位,且為了避開立體障礙,碳氫鍵活化會發生在相同的銠金屬上形成 {Rh2(OAc)2[(C6H4)PPh2](metalated-5d, 5e)} (10d, 10e),而10e的晶體結構更指出兩個碳銠鍵長接近,代表雙銠金屬鍵結的反式影響不大;而位於三苯基膦對位的兩個銠氧鍵結則有顯著差異,可能是苯環的π-acceptor性質,導致對位的銠氧鍵結較長。在催化反應方面,所有的環銠化錯合物特別是8e,於室溫下可選擇性地氧化allylic位置,變為α,β不飽和之羰基化合物,除了具有極佳的反應活性及位向選擇性,且可適用於多種官能基。 仿生雙核金屬錯合物被證明於特定催化系統中,具有特殊的反應活性,普遍認為是在催化過程中,雙金屬間可產生協同效應。因此,本論文第三部分試著將5f、5g分別與Cu(ClO4)2、Ni(OAc)2進行配位反應,可得四種雙核金屬錯合物[(5f)- Cu2(ACN)2(H2O)4][ClO4]4 (11f)、[(5g)Cu2(ClO4)2][PF6]2 (11g)、[(5f)Ni2(OTFA)2- (H2O)6] [OTFA]2 (14f)及[(5g)Ni2(OTFA)4(H2O)] (14g),且皆可以X光單晶繞射分析得知其空間結構,而紫外光及紅外線吸收光譜也可進一步確認之。於電化學分析指出11f和11g皆有兩組還原電位及一組氧化電位,其中11g的配體有較強的π-acceptor性質,可穩定低氧化態的中心金屬,使其HOMO下降,銅金屬較不易被氧化。 雙核銅金屬錯合物11g於多種氧化反應皆有著不錯的反應性,其中可將苯甲醇選擇性地氧化至苯甲酸苄酯,若改以單銅或含有三聯

關鍵字

碳氫鍵活化 雙金屬 雙銠 雙銅 雙鎳

並列摘要


In this thesis, we have prepared a series of 1,9,10-anthyridine-based multidentate ligands (5a~5k), coordinating with various transition metal ions including Pd, Rh, Cu, Ni, which could be applied in many catalytic reactions. Coordination of 5a, 5b with Pd(OAc)2 yielded the cyclopalladated complexes [(5a)PdBr(H2O)] (6a), [(5b)2Pd2(OAc)2] (6b). Treatment of 6a, 6b with PPh3 resulted in the formation of stable dimer cyclopalladated complexes {[(5a)2Pd2(PPh3)2]Br2} (7a), {[(5b)2Pd2(PPh3)2] } (7b), which was capable to be converted to the original ones by using sulfur or gold (I) complex to break the Pd-C bond. X-ray structural cha- racterization showed that the Pd-N bond trans to the carbon atom was longer than the other one due to the trans-influence. The use of cyclopalladated complexes in cataly- sis has been increased significantly because of their strong σ-donor nature. It exhibit- ed good catalytic activities on the catalysis of Suzuki-Miyaura coupling of chloro- arenes with phenylboronic acid in protic solvents like water. Besides, it was able to catalyze carbon boron bond cross coupling with excellent yields and functional group tolerance. In the second part of this research, reaction of (5a,5c,5d,5e) with Rh2(OAc)4 provided the cyclometalated complexes [Rh2(OAc)3(metalated-5a, 5c, 5d, 5e)] (8a, 8c, 8d, 8e), and the existence of Rh-C bond in axial position could be confirmed by 1H- NMR, 13C-NMR and X-ray crystallography. Under acidic conditions, cleavage of the Rh–C bond in 8e took place to give the corresponding coordination complex- es [Rh2(OAc)3(5e)][PF6] (9e). Treatment of 8d, 8e with PPh3 led to the phosphine- cyclometalated species {Rh2(OAc)2[(C6H4)PPh2](metalated-5d, 5e)} (10d, 10e). X- ray structural determinations revealed that two Rh-C bond distances were quite close to each other, which meaned trans influence from the dirhodium metal-metal bond was not so signi- ficant. However, due to the trans influence, Rh-O bond trans to the carbon atom would longer than the one trans to the phosphorous atom. In the catalytic application, all the cyclorhodated complexes, especially 8e, showed the activity on allylic oxidation to α, β unsaturated carbonyl compounds with outstanding reactivity, regioselectivity and functional group tolerance. Biomimetic bimetallic complexes have been proved to have unique reactivity in specific catalytic system, and widely regarded as the cooperation between metals dur- ing the catalytic reaction. In the third part of this thesis, we have synthesized dimetal complexes [(5f)Cu2(ACN)2(H2O)4][ClO4]4 (11f), [(5g)Cu2(ClO4)2][PF6]2 (11g), [(5f)- Ni2(OTFA)2-(H2O)6][OTFA]2 (14f), [(5g)Ni2(OTFA)4(H2O)] (14g) through complexa- tion of 5f, 5g with Cu(ClO4)2, Ni(OAc)2, and all of the dimetal complexes were determined by single crystal X-ray diffraction. By means of UV-vis and infrared spec- troscopy, the coordination geometry could be further confirmed. Electrochemistry analysis showed that both of dicopper complexes had two reduction potential and one oxidation potential, however, strong π-acceptor nature of terpyridine ligand could stabilize the low-valent central metal, and lower the highest occupied molecular orbi- tal, which might explain why 11g had high oxidation potential. The dicopper complex 11g acted as an effective catalyst toward many kinds of oxidation reactions, such as benzyl alcohol could be selective oxidize to benzyl ben- zoate. Without our designed ligand, the desired esters product weren’t available. It’s worth mentioning that part of the alkyl mono or di-ol could work as well. Furthermore, by means of kinetic experiments and ESI-MASS analysis could confirm our proposed mechanism. The dinickel complex 14g could catalyze not only aryl, but alkyl acid reduction to alcohol with good chemoselectivity. Confirmed by the intermediate’s crystal structure, which indicated that 14g could activate acid through bridging mode, followed by hydrosilylation.

並列關鍵字

C-H bond activation bimetallic dirhodium dicopper dinickel

參考文獻


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(c) 馬義翔 國立臺灣大學化學系碩士論文-雙核銅金屬錯合物之合成與催化探討, 2012.
66. 傅勁逢 國立台灣大學化學系博士論文-氮異環碳烯銥與鈀錯合物之合成及催化研究, 2009.
(d) 李佳翰 國立臺灣大學化學系碩士論文-萘啶雙羧酸根配體之過渡金屬錯合物的合成與催化探討, 2014.
94. 鄧運楨 國立臺灣大學化學系碩士論文-多牙氮配位基之釕與銅錯合物之合成與催化探討, 2013.

被引用紀錄


王泰霖(2016)。雙鈷金屬錯合物的合成與其催化應用〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU201701118

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