ISMSC 2007 - Università degli Studi di Pavia

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PSA 43 Self-assembled fluorescent micellar sensors for pH windows: how to easily tune the window position along the pH axis Piersandro Pallavicini, Yuri Diaz Fernandez, Carlo Mangano, Luca Pasotti and Stefano Patroni Dipartimento di Chimica Generale, Università di Pavia, v.le Taramelli, 12 – 27100 Pavia Micellar fluorescent sensors for pH windows may be self-assembled in water by combining a fluorophore, a lipophilic pyridine derivative and a lipophilic tertiary amine inside the same micelle. In particular 2-dodecylpyridine and N,N-dimethyl-dodecylamine may be advantageously used with pyrene as a fluorophore in TritonX-100 micelles.[1] Being pyridinum and trialkyl amines efficient intramicellar quenchers of pyrene fluorescence (by electron transfer mechanisms), transition from OFF to ON state, and again from ON to OFF state, takes place at pH values corresponding to pyridium and ammonium pKa, as pictorially represented in the scheme. Modulation of the position and amplitude of the fluorescent window along the pH axis has been obtained by changing the substituents on the tertiary amino and pyridine moieties, in order to directly influence their pKa. We now have developed a new and straightforward approach to move at will the fluorescent ON window along the entire pH axis. The pKa of acidic species is modified by micellization with respect to their intrinsic values found in pure water. In particular, changing the overall charge of a micelle results in a change of the observed acidic constants: the more the micellar charge is negative, the lower is the observed deprotonation constant. We thus used only 2-dodecylpyridine and N,N-dimethyl-dodecylamine as bases but we progressively added increasing quantities of sodium dodecyl sulphate (SDS) to TritonX-100 micelles. We observed a shift of the fluorescent window position towards higher pH values with a continuous smooth trend as a function of SDS molar fraction. Potentiometric determination of the protonation constants confirmed that the shift is due to the change in the observed protonation constant of the micellized species. Starting from all-TritonX-100 and ending will all- SDS micelles, the whole “traditional” pH axis (2-12) may be spanned by the ON fluorescent window. [1] Yuri Diaz-Fernandez, Francesco Foti, Carlo Mangano, Piersandro Pallavicini, Stefano Patroni, Aurora Perez-Gramatges and Simon Rodriguez-Calvo, Chem. Eur. J., 2006, 12, 921- 930 A Directed Four-Component Self-Sorting System Roy D’souza and Werner M. Nau* Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany Self-sorting phenomena are a cornerstone in the functioning of biological systems. This ability of molecules to recognize specific other molecules within complex mixtures is less frequently observed in synthetic systems. [1] While thermodynamic versus kinetic control has already been reported for sorting behavior, [2] we now introduce a chemical control element, thereby establishing a show-case of directed self-sorting. SO 3 SO 3 N N O 3S O 3 S SO 3 SO 3 CX4•1 CX4•2 N N -CD•1 -CD•2 O 3S N O3S N N N Zn 2+ O 3 S O 3S Zn 2+ N N N N SO 3 PSA 44 We propose a four-component system, consisting of two hosts (p-sulfonatocalix[4]arene and cyclodextrin) and two guests (1 and 2), as a proof-of-principle. [3, 4] Both hosts have similar affinity to bind to either of the guests. However, upon the addition of Zn 2+ , the preferential formation of a strongly bound ternary complex between Zn 2+ , p-sulfocalix[4]arene and 1 simultaneously induces the complexation of -cyclodextrin with 2. This “clean-up” behavior successfully illustrates the potential of externally regulating the complexity of a system. It takes advantage of the interplay of competitive versus cooperative binding to increase the selectivity of supramolecular interactions in apparently complex multicomponent systems. [1] A. Wu and L. Isaacs, J. Am. Chem. Soc., 2003, 125, 4831-4835. [2] P. Mukhopadhyay, P. Y. Zavalij and L. Isaacs, J. Am. Chem. Soc., 2006, 128, 14093- 14102. [3] H. Bakirci, X. Zhang and W. M. Nau, J. Org. Chem., 2005, 70, 39-46 [4] H. Bakirci, A. L. Koner, M. H. Dickman, U. Kortz and W. M. Nau, Angew. Chem. Int. Ed., 2006, 45, 7400-7404 SO 3
PSA 45 A fast-moving electrochemically-driven molecular shuttle: the biisoquinoline effect. Fabien Durola, Jean-Pierre Sauvage Laboratoire de Chimie Organo-Minerale, UMR 7177 du CNRS Institut de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, 67000 Strasbourg, France Two different copper-complexed [2]rotaxanes have been prepared and their electrochemically triggered motions have been investigated. Both compounds contain the same thread, which consists of a 2,9-diphenyl-1,10-phenanthroline (dpp) chelate and a 2,2',6',2''terpyridine (terpy) unit, whereas the threaded rings are different. In the first case, it is a 30membered ring derived from dpp. In the second compound, the ring incorporates a 8,8'diphenyl-3,3'-bi-isoquinoline (dpbiiq) chelate, which is at the same time non sterically hindering but endocyclic. By playing with the stereoelectronic preferences of copper (I) and copper (II), the ring with its complexed copper atom can be translocated from one station to the other reversibly. For the dpp-containing ring, the electrochemically-driven motion is extremely slow (hours to days). By contrast, the dpbiiq-based system is set in motion very readily, the translation process occuring in the milliseconds to seconds timescale, i.e. at least 4 orders of magnitude faster than for its dpp-based homologue. [1] [1] F. Durola, J.-P. Sauvage, Angew. Chem. Int. Ed., 2007, in press. PSA 46 Efficient synthesis of copper(I)-rotaxane complexes via « click chemistry » Stéphanie Durot a , Pierre Mobian a , Jean-Paul Collin a , Jean-Pierre Sauvage a a Institut de Chimie de Strasbourg, Laboratoire de Chimie Organo-Minérale, Université Louis Pasteur, 4 rue Blaise Pascal, F-67070 Strasbourg cedex, France In the course of the last 15 years, the field of rotaxanes has experienced a spectacular development, mostly in relation to molecular machines [1, 2] and new materials. Threads and rings can be quantitatively assembled using copper(I) as a template. Pseudo-rotaxanes are then converted to rotaxanes by a stoppering reaction, that can be the limiting step, since the reaction conditions have to be compatible with the other functions present in the precursor. The efficient synthesis of new rotaxanes using « click chemistry » is described here. « Click chemistry » [3, 4] is a modular approach that relies on near perfect reactions. These reactions must be wide in scope, give very high yields, proceed from readily available reagents, and be easy to perform (that means ideally, be insensitive to oxygen and water). They should also be selective chemical transformations, and the workup as well as the product isolation should be simple. The prototype of a « click » reaction is the 1,3-dipolar cycloaddition of azides and alkynes, and especially the copper(I)-catalyzed synthesis of 1,2,3-triazoles. This reaction has been used for the synthesis of new copper(I)-rotaxane complexes by a double stoppering approach. The remarkable efficiency of such a strategy has to be emphasized, with yields ranging from 60 to 65 % (scheme 1). [5] The mild reaction conditions of the « click chemistry » methodology are clearly very well adapted to the synthesis of copper(I)-rotaxane complexes, especially when copper(I)-complex precursors are relatively unstable. It is expected that such methodology will also be suitable for more elaborate rotaxanes. N 3 N N Cu N N I N3 O O O O O O N N Cu N N I O O O O O O , PF 6 N3 , PF6 N3 i) 62 % i) 65 % O O N N N N N Cu N N I O O O O O O , PF 6 N N Cu N N I N N O O O N N N N O O O i) 3 eq. 4-[tris[(t-butyl)phenyl]methyl]phenyl propargyl ether 0.5 eq. Cu(CH 3CN) 4.PF 6, 0.4 eq. Na 2CO 3, CH 2Cl 2/CH 3CN (7/3), 20 C, 21 h O , PF6 N N O N Scheme 1: synthesis of a Cu(I)-rotaxane complexes via « click chemistry ». [1] V. Balzani, M. Venturi, A. Credi, Molecular Devices and Machines - A journey into the Nanoworld, Wiley-VCH, Weinheim, 2003. [2] B. Champin, P. Mobian, J.-P. Sauvage, Chem. Soc. Rev. 2007, 36, 358. [3] H. C. Kolb, M. G. Finn, K. B. Sharpless, Angew. Chem. Int. Ed. 2001, 40, 2004 [4] H. C. Kolb, K. B. Sharpless, Drug Discov. Today 2003, 8, 1128. [5] P. Mobian, J.-P. Collin, J.-P. Sauvage, Tetrahedron Lett. 2006, 47.
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nd International Symposium on Macro
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Eric Anslyn University of Texas at
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1 Map of Salice Terme 7 5 6 3 9 2 8
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Symposium Program All sessions will
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11:40 - 12:00 Oral Presentation: V.
Page 11 and 12: PSA 22 Anion Receptors Based On The
Page 13 and 14: PSA 72 Molecular Tectonics: STM Stu
Page 15 and 16: PSB 11 Dual binding properties of p
Page 17 and 18: PSB 57 Removal Of Heavy Metal Ions
Page 19 and 20: 40 years of polyazamacrocycles. A p
Page 21 and 22: PL 5 Anion-Templated Assembly of In
Page 23 and 24: Exercising Demons: Synthetic Molecu
Page 25 and 26: Synthetic Strategies and Structural
Page 27 and 28: Anion binding as a conformational a
Page 29 and 30: Supramolecular control of a metal c
Page 31 and 32: OP 3 Control of molecular architect
Page 33 and 34: Catalyst discovery using dynamic co
Page 35 and 36: Cucurbit[n]uril Molecular Container
Page 37 and 38: OP 15 From non-mesomorphic nature t
Page 39 and 40: OP 19 Pyrrolic Tripodal Receptors f
Page 41 and 42: PSA 1 Efficient synthesis of pseudo
Page 43 and 44: Tetra-Cationic phthalocyanines Yasi
Page 45 and 46: PSA 9 Cell penetrating borosilica n
Page 47 and 48: PSA 13 Halide anion interactions wi
Page 49 and 50: Sensing with cavitands: Moving from
Page 51 and 52: Lead(II) complexation by calix[4]-h
Page 53 and 54: Functional [2×2] Grids Xiao-Yu Cao
Page 55 and 56: Neutral supramolecular systems inco
Page 57 and 58: PSA 33 Ratiometric Ion Sensors by R
Page 59 and 60: A photocontrollable receptor for Cu
Page 61: New emitters for mass spectrometric
Page 65 and 66: Macrocyclic Porphyrin-Bidentate Che
Page 67 and 68: PSA 53 Electronic spectroscopy of e
Page 69 and 70: PSA 57 Self-assembly of calixarene/
Page 71 and 72: PSA 61 Piperazine Containing Polyam
Page 73 and 74: PSA 65 Synthesis of Self-Assembly S
Page 75 and 76: PSA 69 Assembly of Metallomacrocycl
Page 77 and 78: Supra-Biomolecular Tandem Assays -
Page 79 and 80: PSA 77 Synthesis and molecular reco
Page 81 and 82: PSA 81 Reaction of phthalic aldehyd
Page 83 and 84: Binding of perrhenate and pertechne
Page 85 and 86: PSA 89 Supramolecular assemblies of
Page 87 and 88: Polytopic Ligands for the Recovery
Page 89 and 90: PSB 1 Rosette Nanotubes as Scaffold
Page 91 and 92: PSB 5 Towards the development of ne
Page 93 and 94: PSB 9 A Quantitative [2]Rotaxane Sy
Page 95 and 96: Metal Complexes of the Polyether Io
Page 97 and 98: PSB 17 Metal controlled anion inter
Page 99 and 100: Crown Ether-tert-Ammonium Salt Comp
Page 101 and 102: PSB 25 A Minimalist Design for Self
Page 103 and 104: PSB 29 Control of Translation of th
Page 105 and 106: PSB 33 Multinuclear NMR, ESI MS and
Page 107 and 108: PSB 37 New Anthracene-based cycloph
Page 109 and 110: PSB 41 1,3,5-Tris(2-aminophenyl)ben
Page 111 and 112: Simple Isophthalamide Derivatives A
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PSB 49 On Sokolov’s approach to a
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PSB 53 New chromogenic sensors usin
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PSB 57 Removal of heavy metal ions
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PSB 61 Molecular Recognition of Ele
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PSB 65 Switching of Self to non-Sel
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Investigation of -cyclodextrin bind
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Novel ditopic probes for different
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PSB 77 Synthesis, supramolecular ar
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PSB 81 Tripodal polyamines as anion
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PSB 85 Templated Synthesis of Large
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PSB 89 Direct C-C coupling of 1,2,4
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PSB 93 The study of cytotoxicity ef
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PSB 97 Development of innovative so
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Campbell B. PSA 39 Campbell F. PSB
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Jensen L.G. PSA 82 Jeppesen J.O. IL
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Peters A.J. PSB 39 Peters A.J. PSB
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Sponsors of ISMSC 2007 The contribu
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ISMSC 2007 - Università degli Studi di Pavia

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