Thermal-induced reversible ferroelastic phase transition in a new bromethyl-substituted molecular rotor  

作　　者：Bao-Ying Wang Chun-Ting He Bo Huang Wei-Jian Xu Wei Xue Zi-Yi Du Wei-Xiong Zhang Xiao-Ming Chen 

机构地区：[1]Key Laboratory of Bioinorganic and Synthetic Chemistry,Ministry of Education [2]School of Chemistry & Chemical Engineering,Sun Yat-Sen University [3]College of Chemistry & Chemical Engineering,Gannan Normal University

出　　处：《Science China Chemistry》2015年第7期1137-1143,共7页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21290173,21301198);the National Basic Research Program of China(2012CB821706);the Natural Science Foundation of Guangdong(S2012030006240)

摘　　要：A new bromethyl-substituted molecular rotor, [Cu（dabcoCH2Br）（H2O）Br3] （dabcoCH2Br＋=1-（2-bromethyl）-1,4-diazoniabi- cyclo[2.2.2]octane cation）, which belongs to a family of balomethyl-substituted molecular rotors, was synthesized and struc- turally characterized. The reversible phase transition at ca. 250 K was well established for this molecular rotor by thermal analyses, variable-temperature X-ray diffraction, and variable temperature dielectric measurements. The order-disorder trans- formation of the rotator part （dabco moiety） causes ferroelastic phase transition with an Aizu notation of mmmF2/m from high- temperature orthorhombic phase （Pbnm） to low-temperature monoclinic phase （P21/n）. More important, in reference to the density functional theory calculations and structural analyses, the key factors to tune the phase transition behaviors were dis- cussed in detail for this family of halomethyl-substituted molecular rotors.A new bromethyl-substituted molecular rotor, [Cu(dabco CH2Br)(H2O)Br3](dabco CH2Br+=1-(2-bromethyl)-1,4-diazoniabicyclo[2.2.2]octane cation), which belongs to a family of halomethyl-substituted molecular rotors, was synthesized and structurally characterized. The reversible phase transition at ca. 250 K was well established for this molecular rotor by thermal analyses, variable-temperature X-ray diffraction, and variable temperature dielectric measurements. The order-disorder transformation of the rotator part(dabco moiety) causes ferroelastic phase transition with an Aizu notation of mmm F2/m from hightemperature orthorhombic phase(Pbnm) to low-temperature monoclinic phase(P21/n). More important, in reference to the density functional theory calculations and structural analyses, the key factors to tune the phase transition behaviors were discussed in detail for this family of halomethyl-substituted molecular rotors.

关 键 词：ferroelastic phase transition molecular rotor confined space 

分 类 号：O641[理学—物理化学]