Spin-crossover and the LIESST effect in [Fe Co1?(bpp)2][BF4]2 (1.00 =x= 0.77). Comparison with bifunctional solid solutions of iron and cobalt spin-crossover centers
Spin-crossover and the LIESST effect in [Fe Co1?(bpp)2][BF4]2 (1.00 =x= 0.77). Comparison with bifunctional solid solutions of iron and cobalt spin-crossover centers
复制标题
[Fe Co1?(bpp)2][BF4]2 (1.00 =x= 0.77) 中的自旋交叉和 LIESST 效应。
DOI：
10.1016/j.poly.2017.01.029
复制
发表时间：
2017
期刊：
影响因子：
2.6
通讯作者：
Halcrow M
中科院分区：
文献类型：
--
作者：
Halcrow M
[Fe（bpp）2][BF 4] 2和[Co（bpp）2][BF 4]2（bpp = 2，6-二{吡唑-1-基}吡啶）从硝基甲烷-乙醚中共结晶产生分析为[FexCo 1] x（bpp）2][BF 4]2（1.00 ≤x≤ 0.77）的均相多晶材料。这些材料中的热自旋交叉仅涉及铁中心，并且增加钴掺杂剂浓度导致T1/2降低和协同性损失。材料表现出LIESST效应，所有三个样品都呈现相同的T（LIESST）值。LIESST弛豫动力学具有明显的多步特征，这在[Fe（bpp）2][BF 4]2衍生的样品中尚未被发现。
Co-crystallization of [Fe(bpp)2][BF4]2and [Co(bpp)2][BF4]2(bpp = 2,6-di{pyrazol-1-yl}pyridine) from nitromethane-diethyl ether yields homogeneous polycrystalline materials analyzing as [FexCo1‒x(bpp)2][BF4]2(1.00 ≤x≤ 0.77). Thermal spin-crossover in these materials only involves the iron centers, and increasing the cobalt dopant concentration leads to a reduction inT½and a loss of cooperativity. The materials exhibit the LIESST effect, with all three samples presenting the sameT(LIESST) value. LIESST relaxation kinetics have a clear multistep character, which has not been detected before in samples derived from [Fe(bpp)2][BF4]2.Magnetic susceptibility and low-temperature crystallographic data are also presented for the pure precursor complex [Co(bpp)2][BF4]2.