高等无机化学英文课件：wang-part3-1

1、Part 3. Self-Processes Programmed Supramolecular Systems Introcduction: Self-assembly and self-organization in life system, “bottom up” methodology Self-assembly, self-organization, and template Design and self-assembly of inorganic architectures Sol-gel chemistry (zeolites, MCM-41, POM-Periodic Mes

2、oporous Organosilica) Design and self-assembly of organic supramolecular systems, supramolecular polymers Self-recognition, self-republication, and supramolecular chirality Supramolecular materials, nanochemistry and,0. Scope and Goals Engineering down / Top down: Faster speed, lower energy consumpt

3、ion, Limitations to 100 nm (50 nm?) by Engineering down 1) electron tunneling 2) heat dissipation 3) quantum mechanical confinement size dependent energy spectrum 4) difficulty and cost of fabrication,Engineering up / Bottom up Molecular and supramolecular species: 110 nm (10 nm covalent species, ve

4、ry difficult) well defined structures, properties Molecular electronics, switches, Gap between 10 100/1000 nm? How to cross? Molecular self-organization, self-assembly, self-synthesis, programmed system,Self-Assembly in Biological Systems Scale: 110000 nm Self-organization or self-assembly of molecu

5、lar components interact chemically or physically in certain well-defined way Specificity and precision highly directed mutual recognition - convergency Self-check and self-correction Wide diversity in structure and function,2130 identical protein units (158 amino acids) +one RNA of 6390 bp,158 amino

6、 acid500 bp (8% of total genome) If: one protein coat 106 bp,D=18 nm, L= 300 nm,Modular, Convergent, Economic,Modular (2) orientation in order to allow growth through binding of components in the correct relative disposition; (3) termination of the process, i.e., end or stop. In addition, defined se

7、quence of molecular instructions or algorithms or well-defined stages may be involved in the overall process. Cascade system, Sequential self-assembly,Molecular programming Molecular information science, molecular informatics and semiochemistry Information and signal processing and communication at

8、molecular and supramolecular level,3.Self-Assembly of Inorganic Architectures Organic ligands + metal ions Well defined metallo-supramolecular architectures Coordination or formation of complex is in principle an assembly process that occurs spontaneously,Metal ions provide (1)a set of coordination

9、geometries (2)a range of binding strengths, from weak to very strong, and of formation and dissociation kinetics, from labile to inert (3)a variety of photochemical, electrochemical and reactional properties (4)reversible assembly-disassembly of supra- molecular architectures and switchable interact

10、ion sites, for instance, by electrochemical inter-conversion between oxidation status of different coordination geometries,Ligands provide (1)connection of metal ions, multiple binding sites / polytopic (2)control over the supramolecular assembly via shape, size, nature and orientation and dispositi

11、on of binding sites, etc. (3)route for energy / electron transfer / exchange, influence on the properties of metal ions,Thermodynamics of self-assembly of closed, cyclic oligomers and open coordination polymers,Equilibrium between closed species (discrete) and polymers (extended,Convergency and dive

12、rgency,Great diversity: Helicates, chains, triangles, squares, boxes, grids, catenanes, dendrimers,3.1Self-Assembly of Helical Metal Complexes: The Helicates Linear array of metal ions hold together by bridging polytopic ligands helically arranged about the central axis through metal ions See: Chem.

13、 Rev. 1997, 97, 2005-2062 Chem. Rev. 2001, 101, 3457-3497,DNA and metal helicate,Double Helicates Ligand threads + Metal ions,Chirality of helicates,Chirality,Requirement for ligands: Easy synthesis Predictability of coordination behavior desired metal binding domains proper disposition of these dom

14、ains in space flexible spacer Most used ligands: pyridine-type ligands Others: 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

15、+ Octahedral metal centres,mixed 4+2 helicate: CuI2(29)22,Different double helicates,Heterotrinuclear cation FeAg2(59)24,22 nm length,27 nm length,nanoarchitectures,Positive cooperativity effects for double helical Cu-58 complexes,Trisilver (I) complex of 49,Triple helical cation Co2(41)34,Triple he

16、lical cation Eu2(63)36+ 9 coordinate Ln, aromatic stacking,3+3+3 Triple helicate cation CuI3(67)33,Space filling plot of the triple helicate 150,Application of helicates,Ligands containing nucleisides,Deoxyribonucleohelicates DNH Positively charged Periphery hydrogen-bonding bases Interaction with o

17、r binding DNA,Pseudo-crown ether,Preparing knot and catenane,Helicate used to prepare knot,Redox switch,3.2 Rods,3.3 Supramolecular Arrays of Metal Ions. Racks, Ladders, Grids Multi-components (ligands) systems For rings, cages, catenanes, rotaxanes, etc., please see part 1 right：top view height: 1.6 nm, diameter: 2.2 nm (top and bottom), 1.5 nm (middle,Two neighboring nano-wheels showing the packing pa