title: Crystallographic and chiroptical studies on tetraarylferrocenes for use as chiral rotary modules for molecular machines.
abstract: A crystal structure of the racemic form of chiral molecular scissors 1 with a trans configuration at the azobenzene unit (rac-trans-1), in which the scissors adopt a closed geometry with two blade phenyl groups that overlap each other, was successfully determined. X-ray crystallographic determination of the structure of (1S,1'S)-10, which is a derivative of the key precursor of trans-1, was also successful. On the basis of the crystal structure of (1S,1'S)-10, the absolute configuration of 1 and related molecular machines, such as molecular pedal 2, and self-locking rotor 3, which all contain a chiral tetrasubstituted ferrocene module, were determined. A correlation between the absolute configuration and the circular dichroism properties of these molecular machines and their synthetic precursors was also determined.
authors.affiliation: Department of Chemistry and Biotechnology, School of Engineering, Center for NanoBio Integration, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Muraoka
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kinbara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Wakamiya
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Takuzo
authors.initials: T
authors.lastname: Aida