title: Molecular motor-driven abrupt anisotropic shape change in a single crystal of a Ni complex.
abstract: Many molecular machines with controllable molecular-scale motors have been developed. However, transmitting molecular movement to the macroscopic scale remains a formidable challenge. Here we report a single crystal of a Ni complex whose shape changes abruptly and reversibly in response to thermal changes at around room temperature. Variable-temperature single-crystal X-ray diffraction studies show that the crystalline shape change is induced by an unusual 90° rotation of uniaxially aligned oxalate molecules. The oxalate dianions behave as molecular-scale rotors, with their movement propagated through the entire crystalline material via intermolecular hydrogen bonding. Consequently, the subnanometre-scale changes in the oxalate molecules are instantly amplified to a micrometre-scale contraction or expansion of the crystal, accompanied by a thermal hysteresis loop. The shape change in the crystal was clearly detected under an optical microscope. The large directional deformation and prompt response suggest a role for this material in microscale or nanoscale thermal actuators.
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Zi-Shuo
authors.initials: ZS
authors.lastname: Yao
authors.affiliation: Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, Fukuoka 804-8550, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mito
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kamachi
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shiota
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshizawa
authors.affiliation: Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Azuma
authors.affiliation: Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyazaki
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Hyogo 657-8501, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Kuirun
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Nakanishi
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Soonchul
authors.initials: S
authors.lastname: Kang
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kanegawa
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen, Fukuoka 816-8580, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Sato