Rotaxanes and Catenanes as Prototypes of Molecular Machines and Motors

1. Rotaxanes and Catenanes as Prototypes ofMolecular Machines and Motors Christiane Dietrich-Buchecker, Maria Consuelo Jimenez-Molero, Valerie Sartor, and Jean-Pierre Sauvage Laboratoire de Chimie Organo-Minerale, Faculté de Chimie, Université Louis Pasteur, Strasbourg Cedex, France Pure Appl. Chem., Vol. 75, No. 10, pp. 1383–1393, 2003. Derek Dorman Macromolecular Studies December 3, 2004

2. Outline • Nanotechnology (Introduction) • Why NanoTech? • Founding Fathers? • The idea. • The Article • Part I: Cu(l)-Templated synthesis of Catenanes. • Part II: Rotaxanes as molecular machines. • Conclusions

3. Introduction • Nanotechnology • Chemistry is nanoscale! • The development and practical applications of structures and devices on a nanometer scale (between 1 and 100 nanometers). • Nanoscience is the scientific study of the properties of the nanometric world.

4. Feynman the Visionary "There's Plenty of Room at the Bottom, An Invitation to Enter a New Field of Physics" • (presented on December 29th 1959 at the annual meeting of the American Physical Society at the California Institute of Technology): • "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.1"

5. Feynman Challenge 1 The first prize was to reduce the words on a page by 25,000 times so that it could be read by and electron microscope. 2 “And I want to offer another prize …$1,000 to the first guy who makes an operating electric motor -- a rotating electric motor which can be controlled from the outside and, not counting the lead-in wires, that is only 1/64 inch cube.“ 1/64th inch = 0.4 mm = 400 m = 400,000 nm

6. K. Eric Drexler • Engines of Creation: The Coming Era of Nanotechnology6 • Nanobots: Machines that could stack atoms. • Foresight InstituteAKA Nanoists • “Foresight Institute's goal is to guide emerging technologies to improve the human condition. Foresight focuses its efforts upon nanotechnology, the coming ability to build products—of any size—with atomic precision.2”

7. Molecular Machines • In Nanosystems by K. Eric Drexler, many molecular devices are proposed such as this Neon pump7.

8. The Nano Toolbox • Top-Down (Miniaturization) • Lithography • Nano-machining • Nano-manipulation • Bottom-Up (Self-assembly/Synthesis) • Self-assembly • Nucleation and growth • Templating

9. Nanotechnology Today • Industry and nanotechnology • Stain resistant pants (nanofibers blocks the stains) • CPU (Moore’s Law) • Glare-reducing and fog-resistant coatings • Improved cosmetics and sunscreens • Tennis rackets (lighter and stronger due to nanotubes)

10. Nanofunding • NNI (National Nanotechnology Initiative) $849M was requested in 2004 (10% more than 2003) • Nanotech Companies ~1335 (www.nanovip.com) • Lux Research a New York consulting company estimates that $2.6 trillion worth of products by 2014.

11. The Article • Part 1: making catenane • Before: long synthetic routes. • Now: elegant short strategies. • Obtain interlocking rings by Cu(I)-complex template. • Part 2: Creating a muscle-like compound • Use Cu(I)-complex to create rotaxane that will mimic a muscle in funtion.

12. Synthesis of Catenanes • Cu(I) ions and dpp4 prove to associate ideally. • Reaction with the pre-catenane with the diiodo derivative of pentaethylene glycol led to Cu(1)+ form.

13. Free the Metal • The metal free [2]catenane was obtained by treatment of Cu(1)+ with KCN in acetonitrile-dichloromethane-water. • The X-Ray structure conforms interlocking rings.

14. Part 2: Molecular Machine • 3 was synthesized in several steps from commercially available compounds.5 • Reaction of 3 with [Cu(CH3CN)4]PF6 in CH3CN/CH2Cl2 led qualtitatively to 42+ as its PF6- salt. • This reaction was slow as the system reached equilibrium

15. Molecular Machine in Action By exchanging the Cu(I) with Zn(II), the complex will expand and contract. From (CPK) model est., the compound changes ~27%.

16. Conclusion • Strategies based on phenanthroline-type ligands entwined around Cu(I) centers successful and proven effective for preparing gram quantities of canenanes and rotaxanes. • New approach using RCM to form the macrocyclic structures eliminates difficulties with the Cu(1)+ formation. • Rotaxanes muscle-like molecule was synthesized and modeled to show expansion by CPK modeling. • This represents the first unimolecular linear array able to stretch and contract at will under the action of a chemical stimulus.

17. Future Work • Continue research on RCM to synthesis catenanes and rotaxanes. • Acquire experimental data to prove the expansion and contraction of their rotaxane muscle.

18. References • www.feynman.com • www.foresight.org • www.imm.org • Belfrekh, N.; Dietrich-Buchecker, C.; Sauvage, J.;TetrahedronLetters 2001, 42(15), 2779-2781 • Jimenez-Molero, M. C.;Dietrich-Buchecker, C.;Sauvage, J.; Chem. Commun., 2003, 1613-1616 • Drexler, K. E.; Engines of Creation: The Coming Era of Nanotechnology. New York: Anchor Press/Doubleday. • Drexler, K. E.; Nanosystems: Molecular Machinery, Manufacturing, and Computation. New York: John Wiley & Sons.

19. Questions

20. Notes/Ideas • Democritus

21. www.intel.com

22. Nanotechnology by Region Nanotechnology Patents per region Nanotechnology in the world—Government funding (NSF estimation)