Advanced Functional Materials

Cover image for Vol. 17 Issue 5

Special Issue: Molecular Machines and Switches – Dedicated to J. Fraser Stoddart

March, 2007

Volume 17, Issue 5

Pages 671–840

Issue edited by: A. Credi, H. Tian

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. Cover Picture: Nanovalves (Adv. Funct. Mater. 5/2007)

      S. Saha, K. C.-F. Leung, T. D. Nguyen, J. F. Stoddart and J. I. Zink

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200790017

      Interlocked molecular and supramolecular actuators based on rotaxanes can act as gatekeepers at the entrances to nanopores in silica, into which guest dye molecules can be uploaded and then released on demand. Such actuators, or nanovalves (shown in the figure), can be operated using a wide range of stimuli, and can be regarded as the prototypes of highly controllable drug-delivery systems.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. Contents: Adv. Funct. Mater. 5/2007 (pages 671–677)

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200790015

  3. Editorial

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. You have free access to this content
      Big Challenges for Tiny Machines (pages 679–682)

      A. Credi and H. Tian

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200700172

      This Special Issue on molecular machines and switches is dedicated to Prof. J. Fraser Stoddart on the occasion of his 65th birthday. As well as giving a brief summary of Prof. Stoddart's work, this Guest Editorial provides an overview of the contributions to the issue, selected to give a quick yet authoritative look at the field of molecular machines and switches as it stands now, and its direction for the near future.

  4. Feature Articles

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. Nanovalves (pages 685–693)

      S. Saha, K. C.-F. Leung, T. D. Nguyen, J. F. Stoddart and J. I. Zink

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adfm.200600989

      Thumbnail image of graphical abstract

      Interlocked molecular and supramolecular actuators based on rotaxanes can act as gatekeepers at the entrances to nanopores in silica, into which guest dye molecules can be uploaded and then released on demand. Such actuators, or nanovalves (shown in the figure), can be operated using a wide range of stimuli, and can be regarded as the prototypes of highly controllable drug-delivery systems.

    2. Proton and Electron Transfer Control of the Position of Cucurbit[n]uril Wheels in Pseudorotaxanes (pages 694–701)

      V. Sindelar, S. Silvi, S. E. Parker, D. Sobransingh and A. E. Kaifer

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adfm.200600969

      Thumbnail image of graphical abstract

      Known binding properties of the cucurbit[n]uril hosts are utilized in the design and preparation of new, water-soluble “wheel-on-an-axle” inclusion complexes (pseudorotaxanes), in which the average location of the wheel or its sliding motion can be controlled via proton- or electron-transfer reactions (see figure) with suitable functional groups inserted on the axle component.

    3. From Molecular Machines to Microscale Motility of Objects: Application as “Smart Materials”, Sensors, and Nanodevices (pages 702–717)

      I. Willner, B. Basnar and B. Willner

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200601154

      Thumbnail image of graphical abstract

      Photonic or electrical signals trigger mechanical translocations on surfaces: The molecular machine functions are transduced by electrical signals or readout by the resulting surface properties of the systems. Translation of the molecular machine operations into macroscopic motor systems is demonstrated, while mimicking biological assemblies.

    4. Rate Acceleration of Light-Driven Rotary Molecular Motors (pages 718–729)

      M. M. Pollard, M. Klok, D. Pijper and B. L. Feringa

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adfm.200601025

      Thumbnail image of graphical abstract

      Control over the rotary speed of, and, in particular, the means to accelerate, light-driven unidirectional rotary motor systems is the key to their future application. Here, the structural features that influence the rate of rotation of molecular motors that are based on overcrowded alkenes are reviewed. This intriguing and instructive line of research ultimately leads to a motor that is capable of 44 rotations per second—5 × 108 times faster than the original design (see figure).

    5. Artificial Surface-Mounted Molecular Rotors: Molecular Dynamics Simulations (pages 730–739)

      J. Vacek and J. Michl

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200601225

      Thumbnail image of graphical abstract

      The development of artificial surface-mounted molecular rotors has benefited from molecular dynamics simulations (see figure). After a brief survey of the origins of the project, a review of the present understanding of the way in which these simple molecular machines operate is presented.

    6. Molecular Photochemionics (pages 740–750)

      R. Ballardini, P. Ceroni, A. Credi, M. T. Gandolfi, M. Maestri, M. Semararo, M. Venturi and V. Balzani

      Article first published online: 1 FEB 2007 | DOI: 10.1002/adfm.200600992

      Thumbnail image of graphical abstract

      Photochemionic devices are molecular or supramolecular systems wherein information transfer and processing is accomplished by using light, molecules, and ions as input/output signals (see figure). They operate in solution and take inspiration from information processing in living organisms. Advances in this field could lead to the design and construction of a “molecular computer”.

      Corrected by:

      Correction: Molecular Photochemionics

      Vol. 17, Issue 7, 1050, Article first published online: 25 APR 2007

  5. Full Papers

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. Using Molecular Force to Overcome Steric Barriers in a Springlike Molecular Ouroboros** (pages 751–762)

      S. Nygaard, Y. Liu, P. C. Stein, A. H. Flood and J. O. Jeppesen

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200600907

      Thumbnail image of graphical abstract

      The molecular ouroboros is structurally similar to the image of the Serpent biting its own tail (see figure). In function, however, its mode of action resembles a wound spring that either relaxes back down or releases its energy by unraveling.

    2. Tetrathiafulvalene-, 1,5-Dioxynaphthalene-, and Cyclobis(paraquat-p-phenylene)-based [2]Rotaxanes with Cyclohexyl and Alkyl Chains as Spacers: Synthesis, Langmuir–Blodgett Films, and Electrical Bistability (pages 763–769)

      X. Guo, Y. Zhou, M. Feng, Y. Xu, D. Zhang, H. Gao, Q. Fan and D. Zhu

      Article first published online: 1 FEB 2007 | DOI: 10.1002/adfm.200600898

      Thumbnail image of graphical abstract

      Multilayer Langmuir–Blodgett (LB) films of new [2]rotaxanes show excellent switchable electrical bistability (see figure). The new compounds are based on tetrathiafulvalenes (TTFs) with cyclohexyl and alkyl chains as the spacers. These findings will allow for the design and preparation of other multifunctional [2]rotaxanes in the future.

    3. Observation of Structural and Conductance Transition of Rotaxane Molecules at a Submolecular Scale (pages 770–776)

      M. Feng, L. Gao, S. X. Du, Z. T. Deng, Z. H. Cheng, W. Ji, D. Q. Zhang, X. F. Guo, X. Lin, L. F. Chi, D. B. Zhu, H. Fuchs and H.-J. Gao

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200600973

      Thumbnail image of graphical abstract

      Rotaxane molecules have attracted considerable interest because of their performance in molecular electronic devices and nanoscale data-storage media. Low-temperature scanning tunneling microscopy is used to investigate the structure and conductance of single H2 rotaxane molecules (see figure) on a buffered Au(111) substrate at 77 K.

    4. All-Photonic Molecular XOR and NOR Logic Gates Based on Photochemical Control of Fluorescence in a Fulgimide–Porphyrin–Dithienylethene Triad (pages 777–785)

      S. D. Straight, P. A. Liddell, Y. Terazono, T. A. Moore, A. L. Moore and D. Gust

      Article first published online: 29 JAN 2007 | DOI: 10.1002/adfm.200600802

      Thumbnail image of graphical abstract

      A triad molecule consisting of a porphyrin linked to fulgimide and dithienylethene photochromes (see figure) performs as an all-photonic Boolean XOR and NOR logic gate. Photoisomerization of the photochromes records the state of each of the two inputs, and porphyrin fluorescence provides the output.

    5. Bidirectional Ring-Opening and Ring-Closing of Cationic 1,2-Dithienylcyclopentene Molecular Switches Triggered with Light or Electricity (pages 786–796)

      B. Gorodetsky and N. R. Branda

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adfm.200600902

      Thumbnail image of graphical abstract

      The reversible cyclization reaction triggering (see figure) of three bis(N-methylpyridinium)dithienylethene derivatives, differing in the substituents attached to the two C atoms of the photoresponsive hexatriene system involved in forming the new C–C bond, is studied. All three undergo i) ring-closing isomerization when irradiated with UV light or electrochemically reduced, and ii) ring-opening by irradiation with visible light or electrochemical oxidization.

    6. Photoswitches Containing a Dithiafulvene Electron Donor (pages 797–804)

      M. Åxman Petersen, L. Zhu, S. H. Jensen, A. S. Andersson, A. Kadziola, K. Kilså and M. Brøndsted Nielsen

      Article first published online: 29 JAN 2007 | DOI: 10.1002/adfm.200600888

      Thumbnail image of graphical abstract

      The ability of an electron-donating dithiafulvene (DTF) unit (see figure) to tune the optical and photoswitching properties of retinal, diethynylethene, and dihydroazulene chromophores is investigated. In general, the DTF unit induces a significant red-shift in the lowest-energy absorption in all investigated chromophores.

    7. Porphyrin-Based Molecular Rotors as Fluorescent Probes of Nanoscale Environments (pages 805–813)

      K. P. Ghiggino, J. A. Hutchison, S. J. Langford, M. J. Latter, M. A. P. Lee, P. R. Lowenstern, C. Scholes, M. Takezaki and B. E. Wilman

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200600948

      Thumbnail image of graphical abstract

      Fluorescent supramolecular molecular rotors (see figure) derived from SnIV metalloporphyrins show efficient and solvent-viscosity-dependent photophysical properties as a result of orientation effects through a naphthalene diimide modulator and phenolate bridge.

    8. Electroactive Films of Multicomponent Building Blocks (pages 814–820)

      I. Yildiz, J. Mukherjee, M. Tomasulo and F. M. Raymo

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adfm.200600873

      Thumbnail image of graphical abstract

      Multicomponent building blocks incorporating 4,4′-bipyridinium dications and CuI centers adsorb spontaneously on the surface of polycrystalline-Au electrodes. Both redox couples can be addressed independently in the resulting electroactive films. The oxidation of the metal center is, presumably, followed by large amplitude motions involving the folding of one of the four 4,4′-bipyridinium arms (see figure).

    9. Reversible Luminescent Gels Containing Metal Complexes (pages 821–828)

      G. De Paoli, Z. Džolic, F. Rizzo, L. De Cola, F. Vögtle, W. M. Müller, G. Richardt and M. Žinic

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200601042

      Thumbnail image of graphical abstract

      Luminescent organo- and hydrogels (see figure) have been obtained by trapping metal complexes. In particular, the incorporation of a ruthenium compound allows probing of the gel formation through the switching of its emission in transition from liquid to the solidlike gel state.

    10. A Light-Driven Pseudo[4]rotaxane Encoded by Induced Circular Dichroism in a Hydrogel (pages 829–837)

      X. Ma, Q. Wang, D. Qu, Y. Xu, F. Ji and H. Tian

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adfm.200600981

      Thumbnail image of graphical abstract

      Rotaxanes and pseudorotaxanes based on a dumbbell-like component surrounded by cyclodextrin and cucurbituril macrocycles show induced circular dichroism (ICD) changes when irradiated at 360 nm. By irradiating at 430 nm, the original ICD spectra can be obtained but, depending on the components and the physical state of the (pseudo)rotaxanes, a loss in intensity is seen. The shuttling motion of the cyclodextrin unit in these compounds can clearly be deduced using the ICD technique (see figure).

  6. Index

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Editorial
    5. Feature Articles
    6. Full Papers
    7. Index
    1. Author Index and Subject Index Adv. Funct. Mater. 5/2007 (pages 839–840)

      Article first published online: 15 MAR 2007 | DOI: 10.1002/adfm.200790016

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