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1.1 Introduction Yesterday, Today and Tomorrow 1.2 Intermolecular F orces

Basis of Supramolecular Chemistry and Crystal Engineering. 1.1 Introduction Yesterday, Today and Tomorrow 1.2 Intermolecular F orces 1.3 Basic C oncepts of Supramolecular Chemistry 1. 4 Hydrogen-bonding in Crystal Engineering 1. 5 Crystal Engineering of Coordination Polymers.

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1.1 Introduction Yesterday, Today and Tomorrow 1.2 Intermolecular F orces

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  1. Basis of Supramolecular Chemistry and Crystal Engineering 1.1 Introduction Yesterday, Today and Tomorrow 1.2 Intermolecular Forces 1.3 Basic Concepts of Supramolecular Chemistry 1.4 Hydrogen-bonding in Crystal Engineering 1.5Crystal Engineering of Coordination Polymers

  2. 1.5Crystal Engineering of Coordination Polymers • Important basis of coordination polymers and supramolecules • 0-D Supramolecules • Structural control & supramolecular isomerism in low-dimensions • 1D-3D coordination polymers

  3. I. Important basis of coordination polymers and supramolecules: • Coordination geometries of metal ions nodes • * Coordination behavior of a metal atom depends mainly on theelectron configuration, atomic radius, and charge. • For example, d10 metal atom can form linear, trigonal, tetrahedral, and octahedral coordination geometries, whereas d1 and d9 atoms tend square-pyramidal or elongated octahedral coordination geometries. • * Larger (donor or bulky) ligands tend to form lower coordination numbers. • 金属离子的配位几何:取决于其电子构型、原子半径和电荷 • 不同电子构型不同杂化轨道不同配位结构 • 高价态金属高配位数;高半径金属高配位数

  4. I. Important basis of coordination polymers and supramolecules: • Bridging and terminal ligands • * Exo-bidentate ligands: bridging ligands(桥连) organic linkers • * Chelate (螯合): terminating ligand, monodentate ligands can also • be terminating ligandscapping ligands • *Larger (donor or bulky) ligands tend to form lower coordination • numbers.

  5. Coordination geometries of metal ions a-b) AgI, CuI, HgII c) PdII, PtII, CuII, NiII d) ZnII, CoII, CdII e) CuII, ZnII, CdII, MnII f) CuII, ZnII, MnII, CdII, FeII, FeIII, CoII, NiII, etc.

  6. Coordination geometries of transition metal ions Simple: commercially available Complicated: chiral, multi-dentate 多配位点: 桥连配体 Chelate: terminal ligand, Monodentate ligands can also act as terminal ligands Bridging ligand as linker

  7. s键 p键 Coordination Bonding 金属离子杂化轨道 Factors controlling the coordination geometry 高价态金属高配位数 高半径金属高配位数 不同电子构型不同杂化轨道 不同配位结构 大配体体积低配位数 键能:共价 < 配位 < 氢键

  8. Basic factors in constructing coordination polymers of different structures 配位超分子、配位聚合物的组装过程,往往是在给定条件下,多组分体系中不同组分(构筑模块)之间,通过配位键、超分子作用等的导向,进行自组装,形成分子聚集体的过程。 组装过程中,在溶液中或固体产物表面上,会形成多种结构可能不同、能够可逆转化的小组装体(即中间产物)。这些小组装体可能进一步组装出一种或者多种的超分子结构。

  9. 动力学产物的稳定性通常不如热力学产物。 动力学产物是反应速度更快,并且沉积速度可能更快的产物。 组装、结晶条件的不同,就完全可能导致形成不同产物 通常,高的反应物浓度和低的反应温度有利于动力学产物的快速形成。相反,低的反应物浓度和高的反应温度有利于热力学产物的形成。

  10. 影响产物结构的主要因素 • 动力学产物的稳定性通常不如热力学产物。但是,动力学产物是反应速度更快,并且沉积速度可能更快的产物。一般而言,组装、结晶条件的不同,就完全可能导致形成不同产物。一般而言,高的反应物浓度和低的反应温度有利于动力学产物的快速形成。相反,低的反应物浓度和高的反应温度有利于热力学产物的形成。 • 概括起来,在配位聚合物的组装过程中,很多条件因素可以影响产物的结构。这些因素主要包括:反应和结晶的温度、pH值、溶剂、反离子等。很多研究结果表明,对于给定的金属离子和有机配体组成的体系,在不同的反应条件、不同的结晶条件下,产生不同的配位聚合物。因此,如何通过反应与结晶条件控制,获得特定目标聚合结构,是配位聚合物组装的挑战性科学问题。

  11. 通过分子设计可以一定程度上实现定向组装。但是,配位聚合物组装的反应体系往往比较复杂,配位键和超分子作用相对比较弱,在实际工作中,难以仅仅根据分子设计(包括金属离子或簇的选择、配体的结构)来完全准确地预测产物的结构。通过分子设计可以一定程度上实现定向组装。但是,配位聚合物组装的反应体系往往比较复杂,配位键和超分子作用相对比较弱,在实际工作中,难以仅仅根据分子设计(包括金属离子或簇的选择、配体的结构)来完全准确地预测产物的结构。 例如:右边的组装体系可以有三种可能的产物,必须通过合适的条件控制(反离子调节),以获得混合配体的聚合物

  12. II. 0-D Supramolecules 1) A Cyclic Trimeric Complex Keys: bridging + terminal The bridge: mono-deprotonated Pt(IV)  neutral compound Methyl (terminal ligand) A Cyclic Trimeric Platinum(IV) Complex (left) with a Nucleobase: [{PtMe3(9-MeA)}3] (9-MeAH = 9-methyladenine) (right).

  13. 2. 0-D Supramolecules 2) 分子方 Molecular square 要点: 分子设计:平面四边形配位金属离子; 螯合配体;桥连配体 配位性质:M—ONO2为弱键;PtII—N和PdII—N为强、稳定键

  14. General remarks on the 0-D compounds 1)Judicious choice of metal ions. for example, square-planar geometry for molecular squares, linear geometry for molecular bars, etc. Coordination number and geometry 2)Judicious choice of bridging ligands, for example, linear geometry for bars, tripodal geometry for steric molecules, etc. shape, size, flexibility, ligating ability 3)Appropriate terminal ligands to terminate from further aggregation or polymerization. 4)Chemical and physical properties of the metal ions and ligands for functional supramolecules.

  15. A double-strand helicate Keys: Linear vs V-shaped tetrahedral AgI p-p interaction Dalton Trans. 2000, 4182 DNA

  16. A triple-strand helicate [Eu3(L3)3](CF3SO3)9(CH3CN)9(H2O)2 C. Piguet:Chem. Commun.2002, 930 3 Eu’s are wrapped 9-coordinate

  17. 分子识别与螺旋自组装:Oligo Helicate: Let’s twist ! CuI NiII Polypyridyl type ligand + 原理:四面体配位 vs 八面体配位 配体的不同柔性 J.-M. Lehn, Proc. Natl. Acad. Sci. U.S.A. 1993,90, 5394

  18. Remarks on the helices and related species • Appropriate metal ions: coordination number and geometry • Appropriate strand ligand: curved, flexible bridging ligand Tetrahedral metal ion: double-strand 6-coordiante 9-coordinate triple-strand

  19. III 低维聚合物结构调控与超分子异构体 Structural control & supramolecular isomerismin low-dimensions 2-connectors linear zigzag or helical square or grid polygon or circle Supramolecular isomers: Same components & stoichiometry different supramol. structures Supramolecular pseudo-isomers: Same framework components & stoichiometry different framework structures of

  20. Hydrothermal Reactions Cap Hydro(solvo)thermal reaction  Temp:110-180oC pressure:autogenous Teflon Teflon liner Container Applications:  Inorganic Materials  Coordination Polymers  Functional metal complexes  Organic reactions Products: highly stable autoclave

  21. Supramolecular isomers [CuI(2-pytz)] tuned by Reaction Conditions CuI趋于2-4低配位

  22. = Supramolecular Isomers of [CuI(2-pytz)] Isomer I Isomer II Molecular zipper: p-p stacking, etc trans/ cis (2:1) Molecular chair trans/ cis (1:1)

  23. Supramolecular Isomers of [CuI(2-pytz)] Zigzag chain :trans Isomer III Isomer IV = = Helix :trans Chiral, P43212

  24. Synthesis of the [CuI(2-pytz)] isomers Different Conditions Different product NO3-,SO42-, CO32-OH-additive Benzene, dilute solution R = 2-py 不同结晶条件导致不同超分子异构体 张杰鹏等:Chem. Commun. 2005, 1258

  25. DE 能垒 DE↑速度↓ DE改变,途径改变 不同反应、结晶条件导致不同超分子异构体或者不同结构产物的产生

  26. 添加剂对配位聚合物结构的影响 各种化学物种(分子、离子)可以视为添加剂。这些添加剂可以通过促进或者阻碍作用,影响特定结构聚合物的生长和结晶过程,从而导致产物的不同。 这种产物调控的基础是:配位键相对较弱,其生成/断裂具有可逆性

  27. Supramolecular isomers tuned by R-im side-groups & solvents At higher pH & Temp

  28. [Cu(mim)]n mim = 2-methylimidazolate R = Me Zigzag chain Hydrothermal 160oC Cu(NO3)2 + Hmim + NH3 [Cu(mim)]

  29. Zigzag chain [Cu(mim)]n mim = 2-methylimidazolate Configuration tuning R = Me Hydrothermal 160oC Cu(NO3)2 + Hmim + NH3 [Cu(mim)] Chain-like structures: Kinetically favored easily deposited Ring Structures: Thermodynamically favored more soluble

  30. [Cu(mim)]8(tol)(mim = 2-methylimidazolate) :An Octagon Solvothermal Cu(NO3)2 + Hmim + NH3 [Cu(mim)] toluene 广义超分子异构体:pseudo-isomer Guest molecular tuning:Templating Ring structure, hydrophobic Diameter: outside 1.9; inside: 1 nm

  31. [Cu(mim)]10(p-xylene)2(mim = 2-methylimidazolate) :An decagon Guest: p-xylene JACS, 2004, 126, 13218 inside 1.3 nm; outside 2.3 nm

  32. 分子设计: 从Cu(I)离子形成之字链聚合物的分子几何分析,Cu—咪唑—Cu的角度大约在145-152范围之内,而分子多边形相应的夹角分别为:八边形135,九边形140,十边形145。因此,理论上,这一体系可能获得分子多边形产物。 145-152 问题:快速形成、沉积 难以获得 动力学产物 热力学产物

  33. 要将反应体系导向热力学产物分子多边形的形成,必须考虑以下因素:要将反应体系导向热力学产物分子多边形的形成,必须考虑以下因素: ► 降低链状聚合物的形成速度:采用水热条件下Cu(II)离子原位生成Cu(I),同时在反应体系中加入强配位能力的过量氨水分子与Cu(I) 配位,减缓长链结构形成的速度。 ►利用结构合适的模板分子诱导分子多边形,降低过渡态能垒,促进分子多边形的形成。

  34. 实验操作 • 采用水热条件下Cu(II)离子原位生成Cu(I),降低Cu(I)浓度 • 同时在反应体系中加入强配位能力、过量氨水分子与Cu(I) 配位,减缓长链结构形成的速度,即添加抑制剂。 •  加入合适模板分子 • 在组装链聚合物[Cu(mim)]的反应体系反应体系中,加入甲苯或者对二甲苯(占反应体系体积约1/4)作为的模板分子,维持其他反应条件不变,可以分别组装出分子八、十边形,即[Cu8(mim)8]∙toluene 和[Cu10(mim)10]∙(p-xylene)2,其中客体分子甲苯或对二甲苯位于分子多边形的空穴中。

  35. 影响配位聚合物产物结构的反应条件 ► 反应的温度、时间等物理条件 ► 反应体系的pH,模板剂与添加剂,溶剂极性,反应物的浓度、反离子等化学条件

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