Abstract
In this thesis, novel supermolecular pseudorotaxane switches, comprising ferrocenyl group and oligothiophene conjugated group in an axle molecule and dibenzo[24]crown-8 as a ring molecule, have been synthesized to analyze their photo-responsive behaviors in crystal states. The obtained pseudorotaxanes were characterized using 1H NMR spectroscopy, fast atom bombardment mass spectroscopy, and elemental analysis. Crystallographic structure of the pseudorotaxane with bithienyl group was analyzed by single crystal X-ray crystallography. We found that the pseudorotaxane crystals contain chloroform molecule when the crystallization was performed in a chloroform/ether solvent system resulting in the crystals with smoother surface, whereas the crystals do not have any solvent molecules when the crystallization was done in a dichloromethane/ether solvent system. Thermal properties of the single crystals of the pseudorotaxanes were analyzed using polarizing optical microscopy with a hot stage, differential scanning calorimetry, and thermogravimetric analysis. The crystals have a melting point at 178 ºC for the bithiophene pseudorotaxane and 188 ºC for the terthiophene pseudorotaxane. However, these crystals do not show solid-to-solid phase transition, which can be observed for a pseudorotaxane comprising tolyl group instead of oligothiophenes. In addition, photo irradiation test on the pseudorotaxane crystals were performed using 405-nm and 445-nm continuous wave diode lasers incorporating with an optical microscope. The crystals showed dimension change by 405 nm and 445 nm laser irradiation. The crystal length increased with increase in the laser power and maximum change was observed to be 1.229% with the 405-nm laser irradiation with laser power at 25.05 mW. However, area change of a crystal top surface did not follow same tendency. The crystal area reached to the largest area (+0.767%) by 445-nm laser irradiation at 14.99 mW, then this was gradually decreased to +0.483% with increase of the laser power to 24.97 mW.