title: Assembling an alkyl rotor to access abrupt and reversible crystalline deformation of a cobalt(II) complex.
abstract: Harnessing molecular motion to reversibly control macroscopic properties, such as shape and size, is a fascinating and challenging subject in materials science. Here we design a crystalline cobalt(II) complex with an n-butyl group on its ligands, which exhibits a reversible crystal deformation at a structural phase transition temperature. In the low-temperature phase, the molecular motion of the n-butyl group freezes. On heating, the n-butyl group rotates ca. 100° around the C-C bond resulting in 6-7% expansion of the crystal size along the molecular packing direction. Importantly, crystal deformation is repeatedly observed without breaking the single-crystal state even though the shape change is considerable. Detailed structural analysis allows us to elucidate the underlying mechanism of this deformation. This work may mark a step towards converting the alkyl rotation to the macroscopic deformation in crystalline solids.
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Sheng-Qun
authors.initials: SQ
authors.lastname: Su
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: Zi-Shuo
authors.initials: ZS
authors.lastname: Yao
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: You-Gui
authors.initials: YG
authors.lastname: Huang
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: Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Goro
authors.initials: G
authors.lastname: Maruta
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Sadamu
authors.initials: S
authors.lastname: Takeda
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Soonchul
authors.initials: S
authors.lastname: Kang
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kanegawa
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Sato