Piquer Cristina, Grandjean Fernande, Mathon Olivier, Pascarelli Sakura, Reger Daniel L, Little Christine A, Long Gary J
Institut de Physique, B5, Université de Liège, B-4000 Sart-Tilman, Belgium.
Inorg Chem. 2003 Feb 24;42(4):982-5. doi: 10.1021/ic0204530.
The room temperature iron K-edge X-ray absorption near edge structure spectra of (FeHC(3,5-(CH(3))(2)pz)(3))I(2) and (FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2) have been measured between ambient and 88 and 94 kbar, respectively, in an opposed diamond anvil cell. The iron(II) in (FeHC(3,5-(CH(3))(2)pz)(3))I(2)undergoes the expected gradual spin-state crossover from the high-spin state to the low-spin state with increasing pressure. In contrast, the iron(II) in (FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2) remains high-spin between ambient and 78 kbar and is only transformed to the low-spin state at an applied pressure of between 78 and 94 kbar. No visible change is observed in the preedge peak in the spectra of (FeHC(3,5-(CH(3))(2)pz)(3))I(2) with increasing pressure, whereas the preedge peak in the spectra of ((eHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2) changes as expected for a high-spin to low-spin crossover with increasing pressure. The difference in the spin-state crossover behavior of these two complexes is likely related to the unusual behavior of (FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2) upon cooling.
在对顶金刚石砧盒中，分别在环境压力至88千巴和94千巴的条件下，测量了(FeHC(3,5-(CH(3))(2)pz)(3))I(2)和(FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2)在室温下的铁K边X射线吸收近边结构光谱。随着压力增加，(FeHC(3,5-(CH(3))(2)pz)(3))I(2)中的铁(II)经历了预期的从高自旋态到低自旋态的逐渐自旋态转变。相比之下，(FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2)中的铁(II)在环境压力至78千巴之间保持高自旋，仅在78至94千巴的外加压力下转变为低自旋态。随着压力增加，(FeHC(3,5-(CH(3))(2)pz)(3))I(2)光谱中的前缘峰未观察到明显变化，而((eHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2)光谱中的前缘峰随着压力增加呈现出从高自旋到低自旋转变所预期的变化。这两种配合物自旋态转变行为的差异可能与(FeHC(3,5-(CH(3))(2)pz)(3))(BF(4))(2)冷却时的异常行为有关。
