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1、,树枝状高分子简介,2008年9月,从多官能团内核出发，通过支化基元逐步重复生长,形成具有高度支化结构的树枝状三维大分子。,树形大分子的介绍,Tomalia 在1985 年利用发散法首次合成树形聚(酰胺胺)型大分子,Hawker等人在1989年利用收敛法合成树形冠醚大分子,Balzani 等人在1992 年首次报道了有机过渡金属树形大分子,Percec 等人在1995年首次报道了液晶型的树形大分子化合物,树形大分子的发展和研究现状,目前，二十多类，200多种树形大分子被合成出来,树形大分子的合成方法,分散法,收敛法,核心出发逐步引入单体。代数高，分子量大;易有缺陷，产物与反应物不易分离。,构造
2、外围分支，由核心连接。空间位阻，速率慢;缺陷少，产物与反应物易分离。,I.Tomalia.J.Polymer.1985,17,117.C.Hawker,J.Frechet.J.Am.Chem.Soc.1990,112,7638.,C.Dufes,I.F.Uchegbu,A.G.Schatzlein.Adv Drug Deli Rev.2005,57,2177,PAMAM(聚酰胺-胺)合成过程,中心有核内部有空腔，大量支化单元表面均匀分布可修饰的官能基团,体积、形状、功能基以及分子量都可以在分子水平精确控制-单分散性,高度支化，具有规整，精致的完美结构,高代数呈球形。纳米级尺寸。,良好的溶解性，
3、低的黏度。,树形大分子的结构特点和性质,低黏度、高溶解性,纳米层、聚合液晶、超分子,内部受体封装胶团,能量和电子转移,分子识别催化剂、传感器氧化还原特性,外部受体,树形大分子的结构特点和性质,A.M.Caminade.Laboratoire de Chimie de Coordination du CNRS 205,route de Narbonne,31077 Toulouse cedex 4,FRANCE,2005,树形大分子的应用,超分子化学的应用 催化剂方面的应用 生物医学方面的应用 光学方面的应用 其他方面的应用,超分子的应用 主-客体体系,V.Balzani,F.Vgtle.C.R
4、.Chimie.2003,6,867,Fig.1.Schematic representation of(a)a conventional fluorescent sensor and(b)a fluorescent sensor with signal amplification.Open rhombi indicate coordination sites and black rhombi indicate metal ions.The curved arrows represent quenching processes.In the case of a dendrimer,the ab
5、sorbed photon excites a single fluorophore component,i.e.quenched by the metal ion,regardless of its position.,超分子的应用 分子自组装,Y.Liu,M.Zhao,D.E.Bergbreiter.J.Am.Chem.Soc.1997,119,8720,Fig.2.Schematic illustration of the pH-switchable“On/Off”function of the composite film.The polyamine dendrimer units a
6、re covalently attached to the Gantrez polymer network.At high pH the film has a net negative charge that excludes anions but passes cations;at low pH it is positively charged and excludes cations but passes anions;and at intermediate pH,it passes both cations and anions.,催化剂方面的应用,纳米尺寸，形成纳米微环境,催化活性中心
7、有可变性,减少金属催化剂流失,分子结构可精确控制,Fig.3.Shape-selective olefin epoxidation using dendrimers with a manganese(iii)porphyrin core as catalysts,P.Bhyrappa,J.K.Young,J.S.Moore,K.S.Suslick.J.Mol Catal A.1996,113.109,催化剂方面的应用,Fig.4.Epoxidation results for the intermolecular mixture of alkenes.The ratios of the epo
8、xides are normalized with respect to corresponding Mn(TPP)+values.Errors are estimated at(5%relative.,Fig.5 A unimolecular reverse micelle that efficiently catalyzes the elimination of tertiary halides.The nonpolar corona(yellow)shields the polar interior(blue)of hydroxyl functionalities,which are a
9、ble to stabilize the carbocation intermediate.,M.E.Piotti,F.Rivera,R.Bond,C.J.Hawker,J.M.J.Frechet.J.Am.Chem.Soc.1999,121,9471,催化剂方面的应用,Table 1.Effect of Changing the Dendrimer Structure and Concentration on the Yield and Turnover Number for the E1 Elimination Reaction(Reaction performed for 43 h at
10、 70 oC,a The molar ratio.,Fig.6 Competitive Hydrogenations of 3-Cyclohexene-1-methanol and CyclohexeneUsing Various Pd Catalysts.Reaction conditions:3-cyclohexene-1-methano l 0.5 mmol,cyclohexene 0.5 mmol,catalyst 5.0 mol of Pd,toluene 12.5 mL,H2 1 atm,30 oC.,树状大分子封装金属粒子（1）小于4 nm纳米粒子，比表面积大、催化效率高（2）表
11、面基团控制溶解性（3）能很好的稳定纳米粒子，并创造纳米微环境（4）能再生使用,M.Ooe,M.Murata,T.Mizugaki,K.Ebitani,K.Kaneda.Nano Lett.2002,2,999,催化剂方面的应用,生物医学的应用,Fig.7 approaches for design of drug delivery systems.,药物载体,内部空腔和结合点可以携带药物。高密度表面基团经过修饰，改变水溶性和靶向作用。毒性较低，通过扩散和生物降解实现药物释放。分子设计实现生物相溶性和降解性。,R.Duncan,L.Izzo.Advanced Drug Delivery Revi
12、ews.2005,57,2215,外层用聚乙二醇修饰的聚芳醚类树形单分子胶束，疏水内层和亲水外层，在水溶液中有很强的增溶能力，每个胶束能包容9-10个疏水性消炎痛药物分子，具有明显的缓释作用。,Fig.9.Structure of the G2 dendritic unimolecular micelle.,药物载体,M.Liu,K.Kono,J.M.J.Frechet.Journal of Controlled Release.2000,65,121,Fig.8.In vitro release profile of indomethacin from the G3 dendritic un
13、imolecular micelle.,病毒：它的体积也小,转染效率就相对较低.核酸：容易受到细胞毒素的损害。质粒DNA：易受到血浆和血清蛋白的降解.脂质体：它有细胞毒性反应。,基因载体,U.Boas,P.M.H.Heegaard.Chem.Soc.Rew.2004,33,43.D.A.Tomalia.Prog.Polym.Sci.2005,30,294,生物医学的应用,基因载体,J.Dennig,E.Duncan.Reviews in Molecular Biotechnology.2002,90,339.,Fig.11 Model of activated dendrimer-mediat
14、ed DNA uptake.In the first step of the transfection process,the DNAactivated-dendrimer complex binds to the surface of the cell.The complex is then taken into the cell by endocytosis,and incorporated into the endosome of the cell.From theendosome the DNA is released into the cytosol.A small percenta
15、ge of the released DNA reaches the nucleus,where it is transcribed into RNA.In the last step the RNA is transported back into the cytosol and then translated into protein.The exact pathway and metabolism of transfectionreagents after release into the cytosol are still unclear.,聚阳离子末端基团：DNA相互作用(紧密结构)
16、有效键合到真核细胞表面 细胞内吞 缓冲细胞内PH,确保复合 物稳定,核磁共振造影剂（MRI）,生物医学的应用,M.Fischer,F.Vgtle.Angew.Chem.Int.Ed.1999,38,884.,大量表面基团和空腔：可以增加造影剂复合物的数量完美结构，大分子尺寸：从血液循环排除慢，成像时间长增加成像的灵敏度和清晰度（驰豫时间长）,H.Kobayashi,S.Kawamoto,T.Saga,N.Sato,T.Ishimori,J.Konishi,K.Ono,K.Togashi,M.W.Brechbiel.Bioconjugate Chem.2001,12,587.,核磁共振造影剂（M
17、RI）,Fig.12.Flowchart of the protocol for preparing Avidin-G6-(1B4M-Gd)254.,Fig.13 Micro-MR image of SHIN3 cell pellets incubated with 4mol of Av-G6Gd,G6Gd,Gd-DTPA,S.Shukla,G.Wu,M.Chatterjee,W.Yang,M.Sekido,L.A.Diop,R.Muller,J.J.Sudimack,R.J.Lee,R.F.Barth,W.Tjarks,Bioconjugate Chem.2003,14,158,硼中子俘获治
18、疗试剂,叶酸修饰的PAMAM分子可以结合250-400 10B，能够靶向肿瘤细胞，10B与低能中子进行核裂变产生能量以及细胞毒素破坏肿瘤细胞.,癌症治疗,Fig.14 Schematic presentation of an EDA core 3rd generation PAMAM dendrimer G3-DE(1),Na(CH3)3NB10H8NCO(2),andfolic acid FA(3).,F.Vgtle,S.Gestermann,R.Hesse,H.Schwierz,B.Windisch.Prog.Polym.Sci.2000,25,987.,光学方面的应用,光开关,Fig.1
19、5.The photo-responsive azobenzene dendrimer.,树状大分子在其他方面应用,分析化学方面,表面活性剂,电化学应用,纳米材料方面,液晶材料,信息储存材料,结论和展望,树形大分子材料的研究已成为合成化学的研究热点。由于独特的结构和性能，使其在催化、超分子化学、生物医学、光电子材料等领域得到了广泛的研究与应用，被科学家称为“有机化学新家庭”、“二十一世纪的新材料”、“新材料的突破”。目前，树形大分子的研究尚处于探索和积累阶段，许多性能还属未知。随着研究和应用的日益深入，其特殊的结构伴随特异的性能，这种材料必将在多个领域显示广阔的应用前景。,参考文献,I.Tom
20、alia.J.Polymer.1985,17,117.C.Hawker,J.Frechet.J.Am.Chem.Soc.1990,112,7638.C.Dufes,I.F.Uchegbu,A.G.Schatzlein.Adv Drug Deli Rev.2005,57,2177V.Balzani,F.Vgtle.C.R.Chimie.2003,6,867Y.Liu,M.Zhao,D.E.Bergbreiter.J.Am.Chem.Soc.1997,119,8720P.Bhyrappa,J.K.Young,J.S.Moore,K.S.Suslick.J.Mol Catal A.1996,113.
21、109 M.E.Piotti,F.Rivera,R.Bond,C.J.Hawker,J.M.J.Frechet.J.Am.Chem.Soc.1999,121,9471 M.Ooe,M.Murata,T.Mizugaki,K.Ebitani,K.Kaneda.Nano Lett.2002,2,999R.Duncan,L.Izzo.Advanced Drug Delivery Reviews.2005,57,2215M.Liu,K.Kono,J.M.J.Frechet.Journal of Controlled Release.2000,65,121U.Boas,P.M.H.Heegaard.Ch
22、em.Soc.Rew.2004,33,43.D.A.Tomalia.Prog.Polym.Sci.2005,30,294J.Dennig,E.Duncan.Reviews in Molecular Biotechnology.2002,90,339.M.Fischer,F.Vgtle.Angew.Chem.Int.Ed.1999,38,884.H.Kobayashi,S.Kawamoto,T.Saga,N.Sato,T.Ishimori,J.Konishi,K.Ono,K.Togashi,M.W.Brechbiel.Bioconjugate Chem.2001,12,587 S.Shukla,G.Wu,M.Chatterjee,W.Yang,M.Sekido,L.A.Diop,R.Muller,J.J.Sudimack,R.J.Lee,R.F.Barth,W.Tjarks,Bioconjugate Chem.2003,14,158F.Vgtle,S.Gestermann,R.Hesse,H.Schwierz,B.Windisch.Prog.Polym.Sci.2000,25,987,谢谢大家！,
