主客体化学newppt课件.ppt

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1、冠醚及其类似物：穴状配体，开链配体和球状配体的主-客体化学Host-guest chemistry of crown ethers (coronands), podands, cryptands, and spherandsHost or receptor: crown ether, etc. Guest or substrate: metal ion, etc. ,1. 冠醚的发现1967， C. J. Pedersen偶然获得, (1987 Nobel奖),KMnO4 + 冠醚 溶于苯或氯仿 K+ 离子掉进了冠醚分子的洞中：,由此开创了冠醚类化合物、主-客体化学、分子识别的研究乃至开创了超

2、分子化学。,Valinomycin (left) gives a strong and selective complex (right) in which a K+ ion is included in the macrocyclic cavity.,2. 冠醚类化合物的种类和结构,冠醚（crown ethers，单环体系）,穴状配体（cryptands，多环体系）由 J. M. Lehn引入1987 Nobel奖,开链配体（podands）,其他“组合”配体：octopus & lariat ethers,其他“组合”配体：spherands （Cram 引入，1987Nobel奖）,3.

3、 冠醚类化合物的性质和分子识别冠醚的两亲性(亲脂性和亲水性)和溶解性：不同的溶剂中构象不同,配合物在非极性溶剂中更稳定,冠醚对碱金属阳离子的配合球形识别(Spherical Recognition)冠醚环大小的选择效应,环过大时能容纳两个阳离子,对过渡金属的配合 配位原子的变化 N或S替代O，改变配位行为（HSAB理论）,配体的拓扑效应,配合物形成速度（动力学）： 穴醚（慢） 冠醚 开链醚（快）配合物稳定性（热力学）： 穴醚（稳定） 冠醚 开链醚（易变）,通过改变配位原子的种类，环的大小，拓扑等可以改变冠醚类配体的选择性,For recognition of transition metal,

4、 lanthanide and actinide ions, depending on the coordination feature of the ion and the nature, number and disposition of binding sites, as well as to their rigidty,刚性大环,医学上的应用：抑制病毒、病菌生长， 清除重金属，抗肿瘤等。,光活性穴状配体+铕或铽,冠醚类似物结构和分子识别的拓展1. 对质子的“配合”：内部氢键,2. 四面体识别NH4+,Tetrahedral Recognition,3. 胺类离子的识别Ammonium

5、Related Substrates,4. 中性分子的识别 Binding and Recognition of Neutral Molecules Hydrogen bonding, - stacking.,5. 阴离子的识别, Recognition of Anionic Substrate Recognition of halides and N3-,Recognition of carboxylates,N-protonated forms can bind anions.,6. 基于bipy的配位体,上：肠杆菌素+Fe3+Kf=1052下：肠杆菌素模拟物 + Fe3+(6b): Kf

6、=1059,Metallacrown, a class of metallamacrocycles金属氮杂冠醚See, for example,B. Kwak, et al., Inorg. Chem., 1998, 37, 3599.S. Lin, et al., J. C. S., Dalton Trans., 2002, 1595.S. X. Liu et al., Angew. Chem. Int. Ed., 2001, 40, 1085.J. J. Bodwin et al., Coord. Chem. Rev., 2001, 216-217, 489.,12-C-4 O-CH2-C

7、H2-O,12-MC-4 O-M-N-O,Ligand binding mode,MmXxA-MC-B,Aggregates of metallacrown,For molecular recognition,Application:MagnetismMolecular recognition, host-guest chemistrySensorLiquid crystal,3.1Self-Assembly of Helical Metal Complexes: The HelicatesLinear array of metal ions hold together by bridging

8、 polytopic ligands helically arranged about the central axis through metal ions,Double HelicatesLigand threads+Metal ions,Requirement for ligands:Easy synthesisPredictability of coordination behaviordesired metal binding domains proper disposition of these domains in space flexible spacerMost used l

9、igands: pyridine-type ligandsOthers: pyrrole-type, ,Possible types of helicate formed by ligands of bidentate metal-binding domains with four-coordinate and six coordinate metal ions,4+4 helicate: CuI2(12)22+Tetrahedral metal centres,6+6 helicate: CdII2(24)24+Octahedral metal centres,mixed 4+2 helic

10、ate: CuI2(29)22+,Heterotrinuclear cation FeAg2(59)24+,22 nm length,27 nm length,nanoarchitectures,Trisilver (I) complex of 49,Positive cooparativity effects for double helical Cu-52 complexes,Ligands containing nucleisides,DeoxyribonucleohelicatesDNHPositively chargedPeriphery hydrogen-bonding basesInteraction with or binding DNA?,Chirality of helicates,Triple helicalcation Co2(41)34+,Triple helicalcation Eu2(63)36+9 coordinate Ln, aromatic stacking,3+3+3Triple helicate cation CuI3(67)33+,Space filling plot of the triple helicate 150,