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Molecular Shuttle (molecular + shuttle)
Selected AbstractsDistinct Nanostructures from a Molecular Shuttle: Effects of Shuttling Movement on Nanostructural MorphologiesADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Weidong Zhou Abstract A solvent driven molecular shuttle that contains a TCBD chromophore and in which the macrocycle can be positioned close to or far from the TCBD unit with a change of solvent is prepared. Several distinct nanostructures are obtained by control of the shuttling movement of the macrocycle: i) in a mixed solvent of CHCl3/n -C6H14 (1/1, v/v), the macrocycle locates at the peptide station, and interlaced nanofibers form as a result of the extended intermolecular dipole,dipole interactions of the TCBD units; ii) in a solvent of dimethyl sulfoxide, the macrocycle moves along the long alkyl-chain, and worm-like nanoparticles form because the macrocycle obstructs the intermolecular dipole,dipole interactions of the TCBD units. This system confirms that the molecular aggregation behaviors can be controlled by the shuttling movement of the macrocycle. Exploitation of the molecular shuttle to control the molecular aggregation behaviors will provide greater understanding in the field of molecular shuttle applications. [source] Photoinduced Shuttling Dynamics of Rotaxanes in Viscous Polymer SolutionsADVANCED FUNCTIONAL MATERIALS, Issue 21 2009Dhiredj C. Jagesar Abstract The effect of external friction, caused by medium viscosity, on the photoinduced translational motion in a rotaxane-based molecular shuttle 1 is investigated. The shuttle is successfully operated in solutions of poly(methacrylonitrile) (PMAN) of different molecular weights in MeCN and PrCN. The viscosity of the medium is tuned by changing the PMAN concentration. The rheological behavior of the polymer solution gives insight into the structure of the polymer solution on the microscopic scale. In PrCN, the entanglement regime is reached at lower concentration than in MeCN. This is also reflected by the effect on the shuttling: in the PrCN/PMAN system, a larger viscosity effect is observed compared to MeCN/PMAN. The shuttle is found to be slowed down in the polymer solutions but is still active at high viscosities. The observed retardation effect on the kinetics of shuttling in MeCN/PMAN and PrCN/PMAN can be correlated to the PMAN concentration through the hydrodynamic scaling model. The Stokes,Einstein relationship proves inadequate to correlate the shuttling rates to macroscopic viscosity, but the dependence of the shuttling rate on the bulk viscosity fits well to a commonly observed power-law relationship. The viscosity effect on the shuttling is found to be weak in all cases. [source] Distinct Nanostructures from a Molecular Shuttle: Effects of Shuttling Movement on Nanostructural MorphologiesADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Weidong Zhou Abstract A solvent driven molecular shuttle that contains a TCBD chromophore and in which the macrocycle can be positioned close to or far from the TCBD unit with a change of solvent is prepared. Several distinct nanostructures are obtained by control of the shuttling movement of the macrocycle: i) in a mixed solvent of CHCl3/n -C6H14 (1/1, v/v), the macrocycle locates at the peptide station, and interlaced nanofibers form as a result of the extended intermolecular dipole,dipole interactions of the TCBD units; ii) in a solvent of dimethyl sulfoxide, the macrocycle moves along the long alkyl-chain, and worm-like nanoparticles form because the macrocycle obstructs the intermolecular dipole,dipole interactions of the TCBD units. This system confirms that the molecular aggregation behaviors can be controlled by the shuttling movement of the macrocycle. Exploitation of the molecular shuttle to control the molecular aggregation behaviors will provide greater understanding in the field of molecular shuttle applications. [source] Parking and Restarting a Molecular Shuttle In SituCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2008Nai-Chia Chen Abstract Herein we report an easy-to-synthesize [2]rotaxane, which incorporates two ionic monopyridinium stations and one 2,2,-bipyridine station as the shaft of the dumbbell-shaped component and a bis- p -xylyl[26]crown-6 (BPX26C6) unit as the macrocyclic component. In this molecular shuttle, the BPX26C6 unit can be docked selectively on either the central 2,2,-bipyridine station or one of the two terminal pyridinium stations, and subsequently, returned to its shuttling molecular motion through the in situ addition of simple reagents (acid/base or metal ion/metal-ion-complexing ligand pairs). [source] A [3]Rotaxane with Three Stable States That Responds to Multiple-Inputs and Displays Dual Fluorescence AddressesCHEMISTRY - A EUROPEAN JOURNAL, Issue 20 2005Da-Hui Qu Abstract A [3]rotaxane molecular shuttle containing two ,-cyclodextrin (,-CD) macrocycles, an azobenzene unit, a stilbene unit, and two different fluorescent naphthalimide units has been investigated. The azobenzene unit and the stilbene unit can be E/Z -photoisomerized separately by light excited at different wavelengths. Irradiation at 380 nm resulted in the photoisomerization of the azobenzene unit, leading to the formation of one stable state of the [3]rotaxane (Z1- NNAS-2CD); irradiation at 313 nm resulted in the photoisomerization of the stilbene unit, leading to the formation of another stable state of the [3]rotaxane (Z2- NNAS-2CD). The reversible conversion of the Z1 and Z2 isomers back to the E isomer by irradiation at 450 nm and 280 nm, respectively, is accompanied by recovery of the absorption and fluorescence spectra of the [3]rotaxane. The E isomer and the two Z isomers have been characterized by 1H NMR spectroscopy and by two-dimensional NMR spectroscopy. The light stimuli can induce shuttling motions of the two ,-CD macrocycles on the molecular thread; concomitantly, the absorption and fluorescence spectra of the [3]rotaxane change in a regular way. When the ,-CD macrocycle stays close to the fluorescent moiety, the fluorescence of the moiety become stronger due to the rigidity of the ,-CD ring. As the photoisomerization processes are fully reversible, the photo-induced shuttling motions of the ,-CD rings can be repeated, accompanied by dual reversible fluorescence signal outputs. The potential application of such light-induced mechanical motions at the molecular level could provide some insight into the workings of a molecular machine with entirely optical signals, and could provide a cheap, convenient interface for communication between micro- and macroworlds. [source] Synthesis of Fullerene-Stoppered Rotaxanes Bearing Ferrocene Groups on the Macrocycle,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2010Aurelio Mateo-Alonso Abstract The synthesis, characterisation and behaviour of a series of rotaxanes containing a fulleropyrrolidine stopper and two ferrocene moieties on the macrocycle is reported. Remarkably, the presence of large and bulky ferrocene groups does not interfere either in the synthesis or in the translocation of the macrocycle induced by ,,, interactions between the macrocycle and the fullerene. The synthetic routes developed can also be applied to the preparation of rotaxane scaffolds that can be complexed to [Ru(CO)TPP] by axial coordination. Overall, the synthetic routes presented herein provide an efficient way to prepare a variety of rotaxanes and molecular shuttles with potential applications in different fields. [source] Directed attachment of antibodies to kinesin-powered molecular shuttlesBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009Amanda Carroll-Portillo Abstract Biomolecular motors, such as kinesin, have been used to shuttle a range of biological and synthetic cargo in microfluidic architectures. A critical gap in this technology is the ability to controllably link macromolecular cargo on microtubule (MT) shuttles without forming extraneous byproducts that may potentially limit their application. Here we present a generalized approach for functionalizing MTs with antibodies in which covalent bonds are formed between the carbohydrate in Fc region of polyclonal antibodies and the positively charged amino acids on the MT surface using the crosslinker succinimidyl 4-hydrazidoterephthalate hydrochloride (SHTH). Antibody-functionalized MTs (Ab-MTs) produced through this approach maintained motility characteristics and antigenic selectivity, and did not produce undesirable byproducts common to other approaches. We also demonstrate and characterize the application of these Ab-MTs for capturing and transporting bacterial and viral antigens. While this approach cannot be applied to monoclonal antibodies, which lack a carbohydrate moiety, it may be used for selectively functionalizing MT shuttles with a variety of carbohydrate-containing cargoes. Biotechnol. Bioeng. 2009; 104: 1182,1188. © 2009 Wiley Periodicals, Inc. [source] | ||||||||||