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1、催化剂的结构(下)寇 元 北京大学 化学与分子工程学院n就催化剂的催化本质而言，似可将催化 剂分为三类：分子筛催化剂，纳米催化 剂，和分子配合物催化剂n络合催化剂的结构特征就在于每一个金 属原子/离子都发挥相同的催化效力注意：三者各有神奇之处6. 络合催化剂 LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityWilkinson开创了络合催化的新时代。Wilkinson的贡献不仅在于建立了高效的均相 催化体系，发现了络合催化剂设计的结构规 律，Wilkin
2、son所创立的研究方法，所采用的 有机膦配体等都直接影响了其后几十年的研 究与工业开发。6. 络合催化剂 LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityPPh3Cl - Rh+1-PPh3PPh36.1 Wilkinson Catalyst 1965年，Wilkinson在制取RhCl3(PPh3)3时, 得到了 RhCl(PPh3)3 ,后人一直称其为Wilkinson催 化剂，一个烯烃加氢制烷烃的催化剂： 14-16e规则LaborotaryLa
3、borotary of Green Catalysis, Peking University of Green Catalysis, Peking University其后，人们发现了一个优秀的氢甲酰化催化剂：6.1 Wilkinson Catalyst LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityCH3 M :1971在络合催 化获得蓬勃发展 之初，人们就想 到了以手性膦中 心实现不对称催 化，但进展甚微 。 6.2 Asymmetric Cat
4、alysisLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversitySedativeTeratogenAsymmetric CatalysisLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityTen of the top 20 pharmaceutical products prescribed in 1994 are
5、molecules possessing at least one chiral center, and strict enantiopurity is required in eight out of these ten molecules.Indinavir, a protease inhibitor currently marketed by Merck and Co., Inc., as CRIXIVAN, an anti-HIV drugAsymmetric CatalysisLaborotaryLaborotary of Green Catalysis, Peking Univer
6、sity of Green Catalysis, Peking University获得手性物质的途径LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University“source” of chirality in productsprocessproductRacemic product mixtureChiral building blocksChiral catalystresolutiontransformationChirality multiplicati
7、on: Asymmetric catalysis获得手性物质的途径LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University手性选择性n常用对映体过量百分数表示%e.e. = 100%R SR + SLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityKagan的贡献1970年代，Kagan创造性 地提出： A: 双齿螯合膦
8、配体B: C2对称性C: 手性膦中心并非必须这直接导致了手性催化在 80年代成为独立的学科并迅 速在工业化上取得进展。Wolf Foundation 2001 Price由天然酒石酸出发，1972LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityKagan的贡献LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityKn
9、owles的同期贡献LDopa，Monsando 80年代初LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University寻找BINAPLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityNOYORI的贡献LaborotaryLaborotary of Green Catalysis, Peking University of
10、Green Catalysis, Peking UniversitySharpless环氧化似乎证明，严格C2对称性的配体也不是必需的，起码 对于加氢和氢甲酰化以外的反应来说。Sharpless环氧化LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University注：Jacobsen的工作LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking Unive
11、rsity6.3 Ziegler-Natta CatalystnZiegler: TiCl4-AlEt3可以催化乙烯齐聚nNatta：丙烯齐聚，会导致聚合物的特异结构n50年代中期实现了聚丙烯工业化CatalystYearYield(kg/g)Isotacticity(%) TiCl31954492 TiCl319711696 MgCl2/TiCl4197532592 MgCl2/TiCl41981130096 MgCl2/TiCl41998500098LaborotaryLaborotary of Green Catalysis, Peking University of Green Cat
12、alysis, Peking University6.3 Ziegler-Natta CatalystLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University6.3 Ziegler-Natta CatalystLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityZiegler-Natta CatalystLaborotar
13、yLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityZiegler-Natta CatalystLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University6.4 Olefin Metathesisn烯烃的双键断裂重新组成新的烯烃n早期的反应是在Ziegler-Natta催化剂上实现的LaborotaryLaborotary of Green
14、Catalysis, Peking University of Green Catalysis, Peking University6.4 Olefin Metathesis由降冰片烯制合成橡胶LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University6.4 Olefin MetathesisMacromol. Chem. 141(1970)161其后，各种金属中心（V, Ta, Mo, W, Ru, Os)被广 泛试探过(R H Schrock)Laborot
15、aryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University6.4 Olefin MetathesisLaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking UniversityOlefin Metathesis最成功的是Grubbs的Ru卡宾络合物系列JACS, 119(1997)3891LaborotaryLaborotary of Green Catalys
16、is, Peking University of Green Catalysis, Peking University6.5 络合催化剂概论n络合催化剂的金属中心一般是单核的, 少部分有 双核的, 没有多核的. 值得注意的是, 尽管双核异 核络合物并不少见, 但用作催化剂却不见报道, 这 与担载催化剂相比有明显差别.n络合催化剂金属中心的三维立体-多位络合决定 了络合催化剂不仅会有chemo-和stereo- selectivity, 而且会有enantio-selectivity, 因此络 合催化体系专一性高, 是高选择性催化体系.n络合催化剂的主要缺点是分离繁琐, 不易为工业 采用. 改进的办法: 1. 两相化 (bi-phase); 2. 固 相化(immobilization); LaborotaryLaborotary of Green Catalysis, Peking University of Green Catalysis, Peking University两相化原理LaborotaryLab
