Controlled Submolecular Translational Motion in Synthesis: A Mechanically Interlocking Auxiliary†
Jeffrey S. Hannam
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorStephen M. Lacy Dr.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorDavid A. Leigh Prof.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorCarlos G. Saiz Dr.
Department of Chemistry, University of St. Andrews, St Andrews, Fife KY16 9AJ, UK
Search for more papers by this authorAlexandra M. Z. Slawin Dr.
Department of Chemistry, University of St. Andrews, St Andrews, Fife KY16 9AJ, UK
Search for more papers by this authorSheila G. Stitchell Dr.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorJeffrey S. Hannam
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorStephen M. Lacy Dr.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorDavid A. Leigh Prof.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorCarlos G. Saiz Dr.
Department of Chemistry, University of St. Andrews, St Andrews, Fife KY16 9AJ, UK
Search for more papers by this authorAlexandra M. Z. Slawin Dr.
Department of Chemistry, University of St. Andrews, St Andrews, Fife KY16 9AJ, UK
Search for more papers by this authorSheila G. Stitchell Dr.
School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK, Fax: (+44) 131-667-9085
Search for more papers by this authorThis work was carried out through the support of the EU Future and Emerging Technologies program MechMol and the EPSRC.
Graphical Abstract
Sew simple: How can you put a molecular bead on a thread when no recognition elements exist between them? A mechanically interlocking auxiliary assembles the macrocycle around a template, controlled submolecular translation moves the ring over the desired substrate and, finally, cleavage of the auxiliary leaves an apparently “impossible” rotaxane (see scheme).
Supporting Information
Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53606_s.pdf or from the author.
Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
References
- 1V. Balzani, A. Credi, F. M. Raymo, J. F. Stoddart, Angew. Chem. 2000, 112, 3484–3530;
10.1002/1521-3757(20001002)112:19<3484::AID-ANGE3484>3.0.CO;2-O Google ScholarAngew. Chem. Int. Ed. 2000, 39, 3348–3391.10.1002/1521-3773(20001002)39:19<3348::AID-ANIE3348>3.0.CO;2-X CAS PubMed Web of Science® Google Scholar
- 2C. P. Collier, E. W. Wong, M. Bělohradský, F. M. Raymo, J. F. Stoddart, P. J. Kuekes, R. S. Williams, J. R. Heath, Science 1999, 285, 391–394.
- 3A. M. Brouwer, C. Frochot, F. G. Gatti, D. A. Leigh, L. Mottier, F. Paolucci, S. Roffia, G. W. H. Wurpel, Science 2001, 291, 2124–2128.
- 4M. C. Jiménez, C. Dietrich-Buchecker, J.-P. Sauvage, Angew. Chem. 2000, 112, 3422–3425;
10.1002/1521-3757(20000915)112:18<3422::AID-ANGE3422>3.0.CO;2-D Google ScholarAngew. Chem. Int. Ed. 2000, 39, 3284–3287.10.1002/1521-3773(20000915)39:18<3284::AID-ANIE3284>3.0.CO;2-7 CAS PubMed Web of Science® Google Scholar
- 5P. Thordarson, E. J. A. Bijsterveld, A. E. Rowan, R. J. M. Nolte, Nature 2003, 424, 915–918.
- 6 Molecular Catenanes Rotaxanes and Knots: A Journey Through the World of Molecular Topology (Eds.: ), Wiley-VCH, Weinheim, 1999.
- 7A. G. Johnston, D. A. Leigh, A. Murphy, J. P. Smart, M. D. Deegan, J. Am. Chem. Soc. 1996, 118, 10 662–10 663.
- 8S. Anderson, H. L. Anderson, Angew. Chem. 1996, 108, 2075–2078;
10.1002/ange.19961081715 Google ScholarAngew. Chem. Int. Ed. Engl. 1996, 35, 1956–1959.
- 9F. Cacialli, J. S. Wilson, J. J. Michels, C. Daniel, C. Silva, R. H. Friend, N. Severin, P. Samori, J. P. Rabe, M. J. O'Connell, P. N. Taylor, H. L. Anderson, Nat. Mater. 2002, 1, 160–164.
- 10V. Dvornikovs, B. E. House, M. Kaetzel, J. R. Dedman, D. B. Smithrud, J. Am. Chem. Soc. 2003, 125, 8290–8301.
- 11D. A. Leigh, A. Murphy, J. P. Smart, A. M. Z. Slawin, Angew. Chem. 1997, 109, 752–756;
10.1002/ange.19971090711 Google ScholarAngew. Chem. Int. Ed. Engl. 1997, 36, 728–732.
- 12M. R. Craig, M. G. Hutchings, T. D. W. Claridge, H. L. Anderson, Angew. Chem. 2000, 112, 1105–1108;
10.1002/(SICI)1521-3757(20000317)112:6<1105::AID-ANGE1105>3.0.CO;2-H Google ScholarAngew. Chem. Int. Ed. 2001, 40, 1071–1074.10.1002/1521-3773(20010316)40:6<1071::AID-ANIE10710>3.0.CO;2-5 CAS PubMed Web of Science® Google Scholar
- 13Within the context of a recent book and paper (V. Balzani, A. Credi, M. Venturi, Chem. Eur. J. 2002, 8, 5524–5532;
10.1002/1521-3765(20021216)8:24<5524::AID-CHEM5524>3.0.CO;2-J CAS PubMed Web of Science® Google ScholarV. Balzani, A. Credi, M. Venturi, Molecular Devices and Machines—A Journey into the Nanoworld, Wiley-VCH, Weinheim, 2003) it was proposed that the term “supramolecular” be expanded from Lehn's original definition of “chemistry beyond the molecule” (i.e., assemblies of two or more molecules or ions held together by noncovalent forces) to include large molecules (e.g., dendrimers, rotaxanes, proteins etc.) which feature functional intramolecular interactions or photophysics. In our view such a revision is unwarranted. When scientific language evolves it needs to retain a precise definition to remain useful (e.g., “acid” to “Lewis acid” or “Brønsted acid”). Consider as a contrary example the term “self-assembly”, which has acquired such an imprecise meaning over recent years that it now conveys virtually nothing as a descriptor. In its currently accepted definition, “supramolecular”—by analogy to the term “molecular”—refers to how the atoms in a structure are held together, not their photophysical properties. It distinguishes molecules from clusters of molecules, for example pseudorotaxanes (host–guest complexes in which the components are free to exchange between bound and unbound species) and rotaxanes (molecules in which the components cannot exchange with outside systems without breaking covalent bonds). It does not matter that their properties can be similar or that bond energies sometimes make it difficult to distinguish between molecular and supramolecular species, just as the timescale-dependent inversion of asymmetric nitrogen atoms does not confer on the term “chirality” any less clear a meaning. Language—especially scientific language—needs to be precise; subject areas, for example, “supramolecular chemistry” or “organometallic catalysis”, on the other hand, should be as broad and inclusive as possible, and have always happily encompassed chemistry not technically suggested by their titles (10.1002/3527601600 Google ScholarJ.-M. Lehn, Supramolecular Chemistry: Concepts and Perspectives, Wiley-VCH, Weinheim, 1995, p. 90).10.1002/3527607439 Google Scholar
- 14In addition to the rotaxane-forming methods based on specific templates for metal-ion coordination, aromatic stacking and hydrogen bonding,[6] cyclodextrins (S. A. Nepogodiev, J. F. Stoddart, Chem. Rev. 1998, 98, 1959–1976), and certain cyclophanes[12] can form rotaxanes of a broad range of substrates through general hydrophobic binding. The trapping of phenolate anions by amide macrocycles can also produce rotaxanes with no recognition elements (
C. Seel, F. Vögtle, Chem. Eur. J. 2000, 6, 21–24;
10.1002/(SICI)1521-3765(20000103)6:1<21::AID-CHEM21>3.0.CO;2-L CAS PubMed Web of Science® Google ScholarR. Shukla, M. J. Deetz, B. D. Smith, Chem. Commun. 2000, 2397–2398), but requires a specific template in the stopper and is apparently of limited generality ( C. A. Schalley, G. Silva, C. F. Nising, P. Linnartz, Helv. Chim. Acta 2002, 85, 1578–1596).
- 15The earliest rotaxane syntheses produced rotaxanes without attractive interactions between the subunits but were carried out under “statistical” conditions, which only generates rotaxanes in low yields (I. T. Harrison, S. Harrison, J. Am. Chem. Soc. 1967, 89, 5723–5724). Other routes to rotaxanes without noncovalent recognition elements between macrocycle and thread have been developed based on covalent bond-directed methods ( G. Schill, H. Zollenkopf, Justus Liebigs Ann. Chem. 1969, 721, 53; K. Hiratani, J.-I. Suga, Y. Nagawa, H. Houjou, H. Tokuhisa, M. Numata, K. Watanabe, Tetrahedron Lett. 2002, 43, 5747–5750).
- 16M. Asakawa, G. Brancato, M. Fanti, D. A. Leigh, T. Shimizu, A. M. Z. Slawin, J. K. Y. Wong, F. Zerbetto, S. Zhang, J. Am. Chem. Soc. 2002, 124, 2939–2950.
- 17G. Brancato, F. Coutrot, D. A. Leigh, A. Murphy, J. K. Y. Wong, F. Zerbetto, Proc. Natl. Acad. Sci. USA 2002, 99, 4967–4971.
- 18A. S. Lane, D. A. Leigh, A. Murphy, J. Am. Chem. Soc. 1997, 119, 11 092–11 093.
- 19T. Da Ros, D. M. Guldi, A. F. Morales, D. A. Leigh, M. Prato, R. Turco, Org. Lett. 2003, 5, 689–691.
- 20Since hydrogen bonding of the DMSO to the peptide and macrocycle provides much of the driving force for displacement of the macrocycle from the template, this switching strategy should be largely independent of the nature of the substrate.
- 21The prefix refers to the position of the macrocycle on the thread.
- 22Silyl ether protections of hydroxyl groups are routinely performed in DMF but DMSO is equally efficacious, a key requirement for the gate functionality with the chosen method of shuttling.
- 23J. O. Jeppesen, J. Perkins, J. Becher, J. F. Stoddart, Angew. Chem. 2001, 113, 1256–1261;
10.1002/1521-3757(20010401)113:7<1256::AID-ANGE1256>3.0.CO;2-0 Google ScholarAngew. Chem. Int. Ed. 2001, 40, 1216–1221.10.1002/1521-3773(20010401)40:7<1216::AID-ANIE1216>3.0.CO;2-W CAS PubMed Web of Science® Google Scholar
- 24One (but not both) of the glycyl Hc protons of alkyl-5 is shielded by δ=1.02 ppm in CDCl3, which indicates that the macrocycle is able to hydrogen bond to the peptide despite being locked on the substrate side of the silyl ether gate.
- 25For examples of postassembly stopper-substitution reactions in rotaxanes see
- 25aS. J. Rowan, S. J. Cantrill, J. F. Stoddart, Org. Lett. 1999, 1, 129–132;
- 25bS. J. Rowan, J. F. Stoddart, J. Am. Chem. Soc. 2000, 122, 164–165;
- 25cS. J. Rowan, S. J. Cantrill, J. F. Stoddart, A. J. P. White, D. J. Williams, Org. Lett. 2000, 2, 759–762;
- 25dD. W. Zehnder, D. B. Smithrud, Org. Lett. 2001, 3, 2485–2487;
- 25eS. H. Chiu, S. J. Rowan, S. J. Cantrill, J. F. Stoddart, A. J. P. White, D. L. Williams, Chem. Eur. J. 2002, 8, 5170–5183.
10.1002/1521-3765(20021115)8:22<5170::AID-CHEM5170>3.0.CO;2-S CAS PubMed Web of Science® Google Scholar
- 26M. G. Stanton, M. R. Gagné, J. Am. Chem. Soc. 1997, 119, 5075–5076.
- 27The tert-butyloxy group is too small to act as a stopper, but tertiary alkoxides are unreactive towards esters and so tBuOK provides a means of generating low concentrations of the reactive stopper primary alkoxide in situ.
- 28F. G. Gatti, D. A. Leigh, S. A. Nepogodiev, A. M. Z. Slawin, S. J. Teat, J. K. Y. Wong, J. Am. Chem. Soc. 2001, 123, 5983–5989.
- 29There are fewer than 30 examples of amide–ester hydrogen bonds in the Cambridge Crystallographic Database and all are from the NH group to the ester carbonyl oxygen atom (C. Alemán, J. J. Navas, S. Muñoz-Guerra, J. Phys. Chem. 1995, 99, 17 653–17 661 and ref. [28]).
- 30G. A. Jeffrey, An Introduction to Hydrogen Bonding, Oxford University Press, Oxford, 1997.
