Phase Transition and Ring-Puckering Motion in a Metal鈥揙rganic Perovskite [(CH2)3NH2][Zn(HCOO)3]

详细信息    查看全文

• 作者：Tetsuo Asaji ; Yoshiharu Ito ; Janez Seliger ; Veselko 沤agar ; Anton Gradi拧ek ; Toma啪 Apih
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：December 27, 2012
• 年：2012
• 卷：116
• 期：51
• 页码：12422-12428
• 全文大小：378K
• 年卷期：v.116,no.51(December 27, 2012)
• ISSN：1520-5215

文摘

Phase transitions in a metal鈥搊rganic perovskite with an azetidinium cation, which exhibits giant polarizability, were investigated using differential scanning calorimetry (DSC) and ¹H nuclear magnetic resonance (NMR) measurements. The DSC results indicated successive phase transitions at 254 and 299 K. The temperature dependence of the spin鈥搇attice relaxation time T₁ determined by NMR indicated that the activation energy for cation ring-puckering motion was 25 kJ mol^鈥? in phase I (T > 299 K). The potential energy at the transition state of puckering is expected to decrease when the potential for the motion becomes asymmetric with decreasing temperature in phases II and III. A possible mechanism for the onset of an extraordinarily large dielectric anomaly is discussed.