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[Structure: see text]. Molecular devices incorporating azobenzene units represent active components of smart systems, as they are capable of exhibiting photoregulated cooperative molecular motion. Herein, we describe the synthesis, X-ray crystal analysis, and photochemical and thermal studies of a xanthene based cyclic azobenzene dimer and its precursor.… (More)
Azobenzenophanes, in which two (2), three (3), and four (4) azobenzene units are connected cyclically by methylene linkers at the meta positions, were synthesized. The effect of ring strain on the structure and the photochemical and the thermal isomerization of azobenzene were investigated. Complex formation with guest species such as alkali metal cations… (More)
Sterically hindered [0.0](3,3')-azobenzenophane exhibits thermal trans-to-cis isomerization to the thermodynamically stable cis-cis isomer, and reversible photochemical isomerization with good fatigue resistance.
Motion is an essential process for many living organisms and for artificial robots and machines. To date, creating self-propelled motion in nano-to-macroscopic-sized objects has been a challenging issue for scientists. Herein, we report the directional and continuous motion of crystals on a glass surface when irradiated simultaneously with two different… (More)
Trans-cis photoisomerization in an azo compound containing azobenzene chromophores and long alkyl chains leads to a photoinduced crystal-melt transition (PCMT). X-ray structure analysis of this crystal clarifies the characteristic coexistence of the structurally ordered chromophores through their π···π interactions and disordered alkyl chains around room… (More)
Multiazobenzene compounds, hexakis-O-[4-(phenylazo)phenoxyalkylcarboxyl]-D-mannitols and hexakis-O-[4-(4-hexylphenylazo)phenoxyalkylcarboxyl]-D-mannitols, exhibit photochemically reversible liquefaction and solidification at room temperature. Their photochemical and thermal phase transitions were investigated in detail through thermal analysis, absorption… (More)
Liquid-crystalline macrocyclic compounds, tethered by two or three azobenzenes bearing alkoxy side chains, exhibit isothermal phase transitions from liquid-crystal to isotropic as well as from crystal to isotropic phases upon light irradiation due to the drastic conformational change of their macrocyclic backbone.
The direct and reversible transformation of matter between the solid and liquid phases by light at constant temperature is of great interest because of its potential applications in various manufacturing settings. We report a simple molecular design strategy for the phase transitions: azobenzenes having para-dialkoxy groups with a methyl group at the… (More)
A new azobenzene-based chromophore was synthesized to create one-dimensional (1D) nanofibers with aggregation-induced emission enhancement characteristics. The enhanced red fluorescence of the fibrous structures can be switched off via mechanical pressure, friction, or heat by pressing, rubbing, or annealing.
[formula: see text] [1.1](3,3')-Azobenzenophane, in which two azobenzenes are cyclically connected by -CH2- chains at the meta positions, has been synthesized. The crystal structures of all isomers have been revealed. This is the first report on the crystal structure of the cis isomer of macrocyclic azobenzenes. The trans,trans isomer was slightly… (More)