含氮雙牙異官能配基鎳或鈀金屬錯合物催化的碳-碳鍵形成反應研究

Studies of Carbon-Carbon Bond Formation Reactions Based on Ni(II) and Pd(II) Catalysts Bearing Nitrogen-Containing Hetero-functional Bidentate Ligands

管仕豪(Shih-Hau Guan)

指導教授 ： 陳竹亭

國立臺灣大學/理學院/化學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.00602

摘要

在本篇論文中將對數種碳-碳鍵形成反應進行探討，其中包括：苯乙烯聚合(styrene polymerization)反應、偶合(cross-coupling)反應以及親核加成(nucleophilic addition)反應。

ㄧ系列新的胺基-噁唑啉雙牙配位基及其鎳(II)金屬錯合物，[(N,N')NiBr2] 4，已被成功地合成出來，並且可應用在苯乙烯的聚合反應上。在助催化劑MAO的活化下，這些鎳錯合物可以非常有效地催化苯乙烯的聚合反應，其活性可以高達約107 g / mol [Ni] × h，而分子量約在數萬的範圍；從13C NMR光譜中可以得知，所得到的聚苯乙烯大多屬於atactic的形式，但在噁唑啉環上的光學中心能夠對聚苯乙烯中isotactic或syndiotactic的含量有所控制。此外催化劑的立體結構以及反應條件對於聚合活性和聚合物性質的影響也將在本篇論文中探討。

其次，我們亦製備了一系列胺基-噁唑啉雙牙配位基鈀(II)金屬錯合物[(N,N')PdCH3Cl] 5以及其陽離子鈀(II)金屬錯合物[(N,N')PdCH3L]+ 7。在中性鈀錯合物5中，其配位化學、動力學現象、幾何異構化現象及其對炔類的插入反應，在本篇論文中均有詳細的探討。另外，從陽離子鈀錯合物7與苯乙烯反應將導致穩定的η3-π-苯甲基鈀錯合物和β-甲基苯乙烯產生，可提供更多的資訊對於鎳鈀金屬用以催化苯乙烯聚合反應所進行的反應機構。

再者，不同的含氮配基鈀金屬錯合物已經被合成出來，這些配基包括：噁唑啉(mono- oxazolines)，胺基-噁唑啉(amino-oxazolines)以及吡啶-唑(pyridyl-azolates)等。在這些化合物中，含吡啶-吡唑雙牙配基的甲基氯化鈀(II)錯合物對於碘苯及丙烯酸丁酯的Heck偶合反應活性非常好，其TON (turn over number)高達95,000,000，可與palladacycle系統相比較。除此之外，此類化合物催化Suzuki-Miyaura偶合反應上也有不錯的表現。另外，在以乙醇為溶劑、Pd(OAc)2為催化劑、KF為鹼的條件下，可在室溫下催化苯硼酸與4-溴乙醯苯酮的耦合反應，且轉化率非常好。

最後，我們合成了一系列含胺基-噁唑啉配位基的烯丙基鈀錯合物，在溶液中，syn-syn及anti-anti的動態轉變可以藉由NOESY核磁共振光譜觀察到；由晶體結構中得知，苯環的位向會受到配基立體效應的影響而有所選擇。而此類化合物經由親核加成反應可以得到線狀或枝狀的產物，由實驗結果得知，親核試劑的立體效應及電子效應以及反應所使用的溶劑極性均會影響均會影響親核試劑攻擊烯丙基的位向選擇性。

關鍵字

碳-碳鍵形成 ； 苯乙烯聚合反應 ； Heck反應 ； Suzuki反應 ； 胺基-噁唑啉

並列摘要

In this thesis, carbon-carbon bond formations are studied through three kinds of reactions: styrene polymerization, cross-couplings and nucleophilic additions.

A new series of Ni(II) complexes [(N,N')NiBr2] bearing bidentate amino-oxazoline ligands have been synthesized and applied for polymerization of styrene. With cocatalyst, MAO, these Ni(II) complexes 4 are highly efficient catalysts for styrene polymerization with activities up to ~107 g / mol [Ni] × h under optimized conditions, which possess the best performance among the catalytic Ni systems now. Effects of the structures of catalysts and the reaction parameters on the activities and characteristic properties for the polymers have been discussed here. From the 13C NMR data, the degree of stereoregularity of the synthesized polystyrene could be moderately controlled by the chiral center in the oxazoline ring although atactic polymers were generally obtained by these Ni(II) catalysts.

The neutral Pd(II) complexes [(N,N')PdCH3Cl] 5 and the cationic complexes [(N,N')PdCH3L]+ 7 were prepared for studying the mechanism for polymerization. For the neutral Pd complexes, their coordination chemistry, dynamic behavior, geometric isomerization, and reactivity toward alkynes have been studied herein. Furthermore, reactions of cationic Pd complexes with styrene, which led to the η3-π-benzyl Pd(II) complexes, made the possible mechanism of the polymerization of styrene for the Ni(II) system.

Neutral Pd(II) complexes were synthesized and involved nitrogen-containing ligands, such as mono-oxazolines, amino-oxazolines and pyridyl-pyrazoles. Among them, the chloromethylpalladium(II) complex with bidentate pyridyl-pyrazole ligands exhibited excellent activities toward Heck coupling reactions with high TONs up to 95,000,000, comparable to the palladacycle systems. In addition, the pyridyl-azolate ligands are good candidates for catalytic Suzuki-Miyaura cross-coupling reactions. In the presence of Pd(OAc)2, KF as base, and such ligands in EtOH, the couplings of aryl bromides with phenylboronic acids could proceed with high conversions at room temperature in the air. Under the same conditions, it could slowly couple aryl chloride with phenylboronic acids, which is rare for Pd catalysts with bidentate nitrogen donor ligands.

Finally, we synthesized a series of cationic allylpalladium(II) complexes bearing asymmetric amino-oxazoline ligands. The isomer interconversion is demonstrated by NOESY spectra to show a syn-syn, anti-anti exchange. Nucleophilic attacks to the Pd complexes would result in the linear and branched products. The regioselectivity is strongly dependent on the steric/electronic properties of the nucleophiles and the polarity of the used solvents.

並列關鍵字

C-C bond formation ； styrene polymerization ； Heck reaction ； Suzuki coupling ； amino-oxazoline

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