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Molecular machines and motors: how can they be set in motion?

Molecular machines and motors: how can they be set in motion?. Various types of signal or driving force have been used or can be considered:. Electrochemical (consumption of electricity) Chemical (a reagent is consumed) Photoredox (light and a reagent are consumed)

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Molecular machines and motors: how can they be set in motion?

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  1. Molecular machines and motors: how can they be set in motion? Various types of signal or driving force have been used or can be considered: Electrochemical (consumption of electricity) Chemical (a reagent is consumed) Photoredox (light and a reagent are consumed) Photonic (light is the only source of energy)

  2. 1MLCT excited state the Ru(bipy)32+family: 3d-d* state 3MLCT dissociative state from the 3MLCT excited state, the strongly antibonding 3d-d state can be populated thermally, depending on the ligand field. This process may be followed byligand expulsion ground state

  3. photochemical expulsion of a Ru(phen)2 fragment from a ring yellow red complex the photochemical process and the thermal reaction are both quantitative

  4. Can one inscribe a Ru(phen)2 fragment in a rod (axial fragment) or in a ring, in order to make a rotaxane or a catenane?

  5. A bis-bipy ligand leading exclusively to a C2 arrangement : Alex von Zelewsky et al. (Fribourg) one of the "CHIRAGENS"

  6. = Ru or Fe resolution: Jérôme Lacour and coworkers

  7. = Ru(II)

  8. Ruthenium Complex

  9. towards rotaxanes whose axis incorporates a Ru(phen)2 fragment

  10. = Ru(II) the threading step

  11. structure of the ruthenium(II) pseudo- rotaxane

  12. = = Ru(II) the real rotaxane could be prepared by classical stoppering: it is photochemically active preliminary results

  13. h  under light irradiation, the ring is decoordinated from the ruthenium centre; thermally, it is recoordinated preliminary results

  14. a [2]catenane constructed around a Ru(diimine)32+ complex used as a template

  15. a [2]catenane constructed around a Ru(diimine)32+ complex used as a template towards light-driven molecular machines

  16. 1MLCT excited state the Ru(bipy)32+family: 3d-d* state 3MLCT dissociative state from the 3MLCT excited state, the strongly antibonding 3d-d state can be populated thermally, depending on the ligand field. This process may be followed byligand expulsion ground state

  17. synthesis strategy

  18. coordination of Ru(II) to the macrocyclic ligand 2+ (21%) M = Ru(II) L = CH3CN

  19. chiral complex (C2 symmetry)

  20. the threading step (i) (56%) (i) : 140° in HOCH2CH2OH

  21. the ring-closing metathesis reaction leading to the catenane [Ru] (68%)

  22. 63-membered ring 50-membered ring two different catenanes have been prepared : 1 is the "small" member of the family and 2 is the "large" one In both compouds, the bipy-incorporating ring is a 42-membered ring

  23. light-driven molecular motions : photochemical decoordination of the 42-membered ring the recomplexation reaction is performed thermally (a few minutes at 140°C or two hours at 80°C in ethylene glycol) both processes are quantitative

  24. photochemical decomplexation and thermal recoordination of the bipy-containing ring in the "large" catenane (42- and 63-membered interlocking rings) 2 2' photochemically, the large catenane is much more reactive than the small one

  25. absorption spectra (visible region) of a CH2Cl2 solution containing 2 ("large" catenane) and NEt4+Cl-, before, during and after irradiation t = 0 s (1), 20 s (2), 40 s (3), 60s(4), 80 s (5), 110 s (6), 150 s (7), 310 s (8).

  26. = bipy fragment light-driven molecular motions h

  27. Photochemical and thermal ligand exchange in a ruthenium (II) complex based on a scorpionate terpyridine ligand • Emma R. Schofield, Jean-Paul Collin

  28. synthesis of the ligand: (i) LDA, dmtpy, Br(CH2CH2O)2THP, thf (ii) HCl(aq) (iii) NEt3, MsCl, DCM, (iv) LiBr, acetone (v) NaH, 4-hydroxybenzonitrile, dmf.

  29. 12+

  30. 12+

  31. 1H NMR spectra (400 MHz) of [1][PF6]2 in pyridine-d5 (9.0-10.5 ppm range) under light irradiation : a : t = 0, b : t = 1, c : t = 2, d : t = 3.5, e : t = 6.5, f : t = 12.5, g : t = 25 mins. Hp2 appears as a doublet at 10.36 ppm in [1]2+ whereas it is strongly shifted upfield in Ru(tpy)(phen)(py)2+, as a result of substitution of the nitrile ligand by pyridine ( = 9.40 ppm)

  32. Light-driven molecular machines based on ruthenium(II) complexes Jean-Paul Collin…Anne-Chantal Laemmel… Yoshio and Junko Furusho…Etienne Baranoff… Didier Pomeranc…Jean-Claude Chambron… Valérie Heitz…Damien Jouvenot…Emma Schofield A [2]catenane constructed around a Ru(diimine)32+ complex Pierre Mobian…Jean-Marc Kern X-ray structures André De Cian…Nathalie Gruber-Kyritsakas… Richard Welter

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