Order–Disorder Transition of Dipolar Rotor in a Crystalline Molecular Gyrotop and Its Optical Change

Successful control of the orientation of the π-electron systems in media has been achieved in certain liquid crystals, making them applicable to devices for optical systems because of the variation in the optical properties with the orientation of the π-electron system. However, because of close packing, changing the orientation of molecules in the crystalline state is usually difficult. A macrocage molecule with a bridged thiophene rotor was synthesized as a molecular gyrotop having a dipolar rotor, given that the dipole derived from the thiophene can rotate even in the crystal. The thermally induced change in the orientation of the dipolar rotors (thiophene ring) inside the crystal, i.e., order–disorder transition, and the variation in the optical properties in the crystalline state were observed

Order–Disorder Transition of Dipolar Rotor in a Crystalline Molecular Gyrotop and Its Optical Change

Successful control of the orientation of the π-electron systems in media has been achieved in certain liquid crystals, making them applicable to devices for optical systems because of the variation in the optical properties with the orientation of the π-electron system. However, because of close packing, changing the orientation of molecules in the crystalline state is usually difficult. A macrocage molecule with a bridged thiophene rotor was synthesized as a molecular gyrotop having a dipolar rotor, given that the dipole derived from the thiophene can rotate even in the crystal. The thermally induced change in the orientation of the dipolar rotors (thiophene ring) inside the crystal, i.e., order–disorder transition, and the variation in the optical properties in the crystalline state were observed

A Molecular Balloon: Expansion of a Molecular Gyrotop Cage Due to Rotation of the Phenylene Rotor

A macrocage molecule with a bridged phenylene rotor has been reported as a molecular gyrotop, because the rotor can rotate even in a crystalline state. Although the most stable cage structure of the molecular gyrotop in a crystal was folded and shrunken at low temperature, expansion of the cage was observed at high temperature due to rapid rotation of the phenylene in a crystal. This phenomenon is analogous to the deflation and inflation of a balloon. Moreover, the unusually large thermal expansion coefficient of the crystal was estimated in the temperature range in which the expansion of the cage was observed, indicating a new function of dynamic states of the molecules

A Molecular Balloon: Expansion of a Molecular Gyrotop Cage Due to Rotation of the Phenylene Rotor

A macrocage molecule with a bridged phenylene rotor has been reported as a molecular gyrotop, because the rotor can rotate even in a crystalline state. Although the most stable cage structure of the molecular gyrotop in a crystal was folded and shrunken at low temperature, expansion of the cage was observed at high temperature due to rapid rotation of the phenylene in a crystal. This phenomenon is analogous to the deflation and inflation of a balloon. Moreover, the unusually large thermal expansion coefficient of the crystal was estimated in the temperature range in which the expansion of the cage was observed, indicating a new function of dynamic states of the molecules

Order–Disorder Transition of Dipolar Rotor in a Crystalline Molecular Gyrotop and Its Optical Change

Successful control of the orientation of the π-electron systems in media has been achieved in certain liquid crystals, making them applicable to devices for optical systems because of the variation in the optical properties with the orientation of the π-electron system. However, because of close packing, changing the orientation of molecules in the crystalline state is usually difficult. A macrocage molecule with a bridged thiophene rotor was synthesized as a molecular gyrotop having a dipolar rotor, given that the dipole derived from the thiophene can rotate even in the crystal. The thermally induced change in the orientation of the dipolar rotors (thiophene ring) inside the crystal, i.e., order–disorder transition, and the variation in the optical properties in the crystalline state were observed

Order–Disorder Transition of Dipolar Rotor in a Crystalline Molecular Gyrotop and Its Optical Change

Successful control of the orientation of the π-electron systems in media has been achieved in certain liquid crystals, making them applicable to devices for optical systems because of the variation in the optical properties with the orientation of the π-electron system. However, because of close packing, changing the orientation of molecules in the crystalline state is usually difficult. A macrocage molecule with a bridged thiophene rotor was synthesized as a molecular gyrotop having a dipolar rotor, given that the dipole derived from the thiophene can rotate even in the crystal. The thermally induced change in the orientation of the dipolar rotors (thiophene ring) inside the crystal, i.e., order–disorder transition, and the variation in the optical properties in the crystalline state were observed

Cage Size Effects on the Rotation of Molecular Gyrotops with 1,4-Naphthalenediyl Rotor in Solution

1,4-Naphthalenediyl-bridged macrocages (<b>2</b>, <b>3</b>, and <b>4</b>) were synthesized as novel molecular gyrotops. Compound <b>2</b> (C14 chains) does not show rotation of the naphthalene ring about an axis in solution. The 1,4-naphthalenediyl moieties of compounds <b>3</b> (C16 chains) and <b>4</b> (C18 chains) show restricted and rapid rotation inside the cage in solution, respectively. Therefore, steric protective effects on the rotation of the rotor in molecular gyrotops can be controlled by changing the size of the cage