Perturbing the spin crossover transition activation energies in Fe(H2B(pz)(2))(2)(bipy) with zwitterionic additions

作者：Costa Paulo; Hao Guanhua; N'Diaye Alpha T; Routaboul Lucie; Braunstein Pierre; Zhang Xin; Zhang Jian; Doudin Bernard; Enders Axel; Dowben Peter A^*

来源：Journal of Physics: Condensed Matter , 2018, 30(30): 305503.

DOI：10.1088/1361-648X/aacd7e

• spin crossover
• zwitterion
• XAS
• SOXIESST

A thermal component to the soft x-ray induced spin crossover transition exists in the switching of a spin crossover compound (complex [Fe{H2B(pz)(2)}(2)(bipy)] (pz = pyrazol-1-yl, bipy = 2,2'-bipyridine) combined with the dipolar molecular additives (zwitterionic p-benzoquinonemonoimine C6H2((center dot center dot center dot) under barH(2))(2)((center dot center dot center dot) under barO)(2)). The addition of the zwitterionic molecule locks the Fe(II) complex in a largely low spin state configuration over an unusually broad temperature range that includes temperatures well above the thermal spin crossover temperature of 160 K. It is demonstrated here that the process of exciting the [Fe{H2B(pz)(2)}(2)(bipy)] moiety, in the presence of with C6H2((center dot center dot center dot) under bar NH2)(2)((center dot center dot center dot) under barO)(2)), to an electronic state characteristic of the high spin state though incident x-ray fluences, has a thermal activation energies are determined to 14-18 meV for a range of mixing ratios from 1:2 to 1:10. Those activation energies are also significantly reduced as compared to values of 60-80 meV found for nanometer thin films of [Fe{H2B(pz)(2)}(2)(bipy)] on SiO2.

• 出版日期2018-8-1