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Functional, Nanoscale Supramolecular Assemblies Reporter: Sichun Yuan Supervisor: Prof. Jian Pei Outline 1. Introduction 2. Formation of supramolecular nanoscale structure 3. Hydrogen-bond-driven supramolecular nanoscale assemblies 4. Coordination-driven supramolecular nanoscale assemblies 5. Functional devices 6. Conclusion 1 1. Introduction , Jean-Marie Lehn Charles. J. Pedersen Donald-James. Cram Nobel Prize laureates in 1987 1. Introduction Supramolecular chemistry , “chemistry beyond the molecule,” bearing on the organized entities of higher complexity that results from the association of two or more chemical species held together by intermolecular forces. Interdisciplinary field of science covering the chemical, physical, and biological features of chemical species. 2 1. Introduction Angew. Chem. Int. Ed. 1988, 27, 1988 Molecular Recognition Process involving both binding and selective substrates by a given receptor molecule. Information storage and read out at supramolecular level. Receptor molecule should contain intramolecular cavity into which the substrate fits, such as macropolycyclic structure. Factors effect host-guest interactions: shape and size of both the host and guest, complementary binding sites and interaction, and medium. 3 Cation cryptate = Cs+ Lehn, J.-M. et, al, J. Am. Chem. Soc. 1975, 97, 5022. Anion cryptate = Cl- F. Schmidtchen. et. al, Chem. Commun, 1984, 1115. 2.Formation of Supramolecular Nanoscale Structures The self-assembly process mainly includes non-covalent interactions such as electrostatic, hydrogen-bonding,π-π stacking, and metal-coordination approaches. 4 The Hydrogen Bond proton donor X H Y proton acceptor X, Y = C, N, O, F, P, S, Cl, Se, Br, and I Strength increase with an increase in the dipole moment of X-H bond and the electron lone pair on atom Y. The thermodynamic stability of H-bonded complexes dependent on the solvent. Structural complementary, enthalpy and entropy effect the end product. The Jorgensen Model of H-Bond The stability attributes to attractive and repulsive secondary interaction. J. Am. Chem. Soc. 1990,112, 2008. J. Am. Chem. Soc. 1991,113, 2810. 5 Schneider’ s Rule The free energy for dimerization consists only of two increment: a contribution of 1.88 kcal / mol for each H-bond and ±0.7 kcal / mol for each attractive or repulsive secondary interaction. Chem. Eur. J. 1996, 2, 1446. Monomers for H-Bond Assembly D. S. Lawrence. et. al, Chem. Rev, 1995, 95, 2229. 6 Cyclic Array Based on H-bond Barr, R. G.; Pinnavaia, T. J. J. Chem. Phys. 1986,90,328. Lehn, J.-H. Tetrahedron. Lett. 1994, 35, 39. Supramolecular Cage Whitesides, G. M. J. Am. Chem. SOC. 1990, 112,6409. 7 Supramolecular Box Lehn, J.-M. Chem. Commun. 1993, 243. Gokel, G. W. J. Am. Chem. Soc, 1994, 116, 6089. Characteristic Features of Thermodynamic Assembly Mediated by Transition Metals Coordination bond is highly directional and of greater strength (10-30Kcal / mol) Kinetically rapid Complementary donor and acceptor and maxima bond number Reversible thermodynamic equilibrium between starting materials and products Proportion of each product is determined by its thermodynamic stability Self-correcting and near-quantitative yield 8 Other Self-Assembly Processes Irreversible self-assembly Assisted self-assembly Directed self-assembly Precursor modification followed by assembly Self-assembly with post-modification Self-assembly with intermittent processing. G. F. Swiegers. et. al, Chem. Rev, 2000, 100, 3483. Organized Hierarchies in The Structure of Coordination Compounds Lehn. J. M. et. al, J. Am. Chem. Soc, 1997, 119, 10956. Stoddart. J. F. et. al, Acc. Chem. Res, 1997, 30, 393. 9 Motif in Coordination Compounds Displaying Disperse Structure Latticed motif Cyclic motif Filamentous motif Interlaced motif Ligands and Metals Used for Coordination Assembly 10 Latticed Motif Grid Lehn, J.-M. et, al, Chem. Commun. 1997, 2231. Rack Lehn, J.-M. et, al, Chem., Int. Ed. Engl. 1995, 34, 1122. Ladder Lehn, J.-M. et, al, Chem. Commun. 1996, 2019. Cyclic Motif Design principles: Stang, P. J. et. al , Chem. Rev. 2000, 100, 853. 11 Chi, X. et. al, Chem. Commun. 1995, 2567. Lehn, J.-M. et, al, Chem. Eur. J. 1999, 5, 113. Stang, P. J. et. al. Acc. Chem. Res. 1997, 30, 502. Stang, P. J. et. al. Organometallics 1997, 16, 3094. 12 Filamentous Motif Sauvage, J.-P. et. al, J. Am. Chem. Soc. 1996, 118, 11972. Constable, E. C. Pure Appl. Chem. 1996, 68, 253. Advances in Inorganic Chemistry, Vol. 46: CA, 1999; Interlaced Motif Ring-in-Ring Michael Schmittel, et. al, Org. Lett., 2002. 4,2289. Sauvage, J.-P. et. al. J. Am. Chem. Soc. 1997, 119, 2656. 13 3.Hydrogen-Bond-Driven Supramolecular Nanoscale Assemblies H-bond modules cooperative other interaction Edge to face π-πinteraction Angew. Chem. Int. Ed. 1996, 108, 1628. 3.Hydrogen-Bond-Driven Supramolecular Nanoscale Assemblies Rebek. J, J. Am. Chem. Soc, 2000, 122, 7876. 14 Formation of 24 cooperative hydrogen bonds drives the spontaneous assembly of a rigid bifunctional trimelamine and bis(barbituric acid) to give selectively the [2 × 2] hydrogen-bonded grid. Chem. Commun., 1999, 1311. Self-Assembled Ionophores by H-Bonding Angew. Chem. Int. Ed. 1997, 36, 2068. 15 4. Coordination-Driven Supramolecular Nanoscale Assemblies Nanoscale self-assemblies built using monodentate ligands (1) 2D nanoscaffolds (2) 3D nanoscale architectures (polyhedra) Nanoscale self-assemblies built from bi- and tridentate ligands (1) 2D assemblies (homo- and heteroleptic aggregation) (2) 3D (heteroleptic) assemblies 2D Nanoscaffolds Nanoscale self-Assemblies built using monodentate ligands A molecular square requires 90° metal corners to define its specific shape. 16 J. Am. Chem. Soc. 1990,112, 5645. J. Am. Chem. Soc. 1994,116, 4981. J. Am. Chem. Soc. 1997,119, 4777. 17 Chem. Commun. 1994, 2313. J. Am. Chem. Soc. 1999,121, 2741 18 3D Nanoscale Architecture (Polyhedra) Induced-fit recognition Mulitopic ligand, Pd(NO3)2, and end-caped Pd(Ⅱ) complexes. J. Am. Chem. Soc. 1995,117, 1649-1650. 19 Chem. Commun. 1998, 1681. Nanoscale Self-Assemblies Built From Bidentate and Tridentate Ligands 2,2’-Bipyridines, [1,10]phenanthrolines, catechols and terpyridines are among the most commonly used chelating ligands for metallo-supramolecular architectures. 20 Two Different Methods for Assembly 2D Assemblies (Homoleptic Aggregates) Chem. Commun. 1996, 551 21 Chem. Eur. J. 2004, 10, 1493 . Angew. Chem. Int. Ed. 2004, 43, 3644. 22 Angew. Chem. Int. Ed. 2004, 43, 3644. 2D Assemblies (Heteroleptic Aggregates) Angew. Chem. Int. Ed. 1997, 36, 1978. 23 M. Schmittel. et. al, Chem. Commun, 2004, 490. 3D (Heteroleptic) Assemblies Linear polytopic ligands, disc-like molecules or cyclophanes and appropriate metal ions. The selective heteroleptic preferring to homoleptic complexation is ascribed to recognition motif and maximun site occupancy. 24 Chem. Eur. J, 1999, 5, 1234. Chem. Commun. 2002, 2566. 25 5. Functional Devices Structure organized and functionally integrated system. Perform function at the molecular and supramolecular level distinct from each components. Components can perform a given function and suitable for incorporation into an organized array 5. Functional Devices 5.1 Supramolecular catalysis 5.2 Photoactive assemblies 5.3 Molecular recognition 26 5.1 Supramolecular Catalysis Container to select reactants by size and shape Place reactants in adequate distance and geometry Use allosteric control over catalysis. Rebek J, Nature, 1996, 382,239. 27 Rebek J, Org. Lett. 2002, 3,327. Fujita M, Chem. Lett, 2002, 598. 28 Allosteric Supramolecular Catalyst Roland. Kramer, Chem. Rev, 2004, 104, 3161. Gianneschi NC, et, al, J. Am. Chem. Soc, 2003, 125, 10508. 29 5.2 Photoactive Assemblies Light-harvesting Electron or energy transfer Photochemical devices Light Conversion by Energy Transfer Angew. Chem. Int. Ed. 1987, 26, 266. 30 Light-Harvesting System Org. Biomol. Chem. 2003, 1, 240. 5.3 Molecular Recognition Polygons and polyhedra (defined cavity) suit for molecular recognition or sensing. Guest inclusion plays a major role in driving the equilibrium to a unique entity. 31 Metallosupramolecular Systems Fujita M, J. Am. Chem. Soc. 2002, 124, 13576. J. Am. Chem. Soc. 1999, 121, 4296. 32 Angew. Chem. Int. Ed. 2003, 42, 3909. 6. Conclusion Metal coordination and hydrogen-bond-driven self-assembly has produced an impressive variety of startling supramolecular architecture. The assemblies display fundamental distinct properties for potential application. The synthetically viable path to the rational design of assemblies is still largely unknown. H-bond-directed self-assembly in water? 33 6. Conclusion Artificial systems, in size and functional complexity, are still lagging far behind biological molecules / entities. Acknowledgement Professor Jian Pei Xinghua Zhou, Yang Jiang, Jinliang Wang, Xiaofei Duan, Jia Luo, Jieyu Wang, and other members in our lab 34 Thank you for your attention! 35