Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, United Kingdom.
Inorg Chem. 2013 Mar 18;52(6):3388-98. doi: 10.1021/ic400125x. Epub 2013 Feb 26.
Reaction of the appropriate Sr3(M(0.5)Ru(0.5))2O7 (M = Ti, Mn, Fe), n = 2, Ruddlesden-Popper oxide with CuF2 under flowing oxygen results in formation of the oxide-fluoride phases Sr3(Ti(0.5)Ru(0.5))2O7F2, Sr3(Mn(0.5)Ru(0.5))2O7F2, and Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5) via a topochemical anion insertion/substitution process. Analysis indicates the titanium and manganese phases have Ti(4+), Ru(6+) and Mn(4+), Ru(6+) oxidation state combinations, respectively, while Mössbauer spectra indicate an Fe(3+), Ru(5.5+) combination for the iron phase. Thus, it can be seen that the soft fluorination conditions employed lead to formation of highly oxidized Ru(6+) centers in all three oxide-fluoride phases, while oxidation states of the other transition metal M cations remain unchanged. Fluorination of Sr3(Ti(0.5)Ru(0.5))2O7 to Sr3(Ti(0.5)Ru(0.5))2O7F2 leads to suppression of magnetic order as the fluorinated material approaches metallic behavior. In contrast, fluorination of Sr3(Mn(0.5)Ru(0.5))2O7 and Sr3(Fe(0.5)Ru(0.5))2O7 lifts the magnetic frustration present in the oxide phases, resulting in observation of long-range antiferromagnetic order at low temperature in Sr3(Mn(0.5)Ru(0.5))2O7F2 and Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5). The influence of the topochemical fluorination on the magnetic behavior of the Sr3(M(0.5)Ru(0.5))2O(x)F(y) phases is discussed on the basis of changes to the ruthenium oxidation state and structural distortions.
在流动氧气中，适当的n = 2的Ruddlesden-Popper氧化物Sr3(M(0.5)Ru(0.5))2O7（M = Ti、Mn、Fe）与CuF2反应，通过拓扑化学阴离子插入/取代过程形成氧化物-氟化物相Sr3(Ti(0.5)Ru(0.5))2O7F2、Sr3(Mn(0.5)Ru(0.5))2O7F2和Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5)。分析表明，钛相和锰相分别具有Ti(4+)、Ru(6+)和Mn(4+)、Ru(6+)氧化态组合，而穆斯堡尔谱表明铁相具有Fe(3+)、Ru(5.5+)组合。因此，可以看出，所采用的温和氟化条件导致在所有三个氧化物-氟化物相中形成高度氧化的Ru(6+)中心，而其他过渡金属M阳离子的氧化态保持不变。Sr3(Ti(0.5)Ru(0.5))2O7氟化生成Sr3(Ti(0.5)Ru(0.5))2O7F2时，随着氟化材料接近金属行为，磁有序受到抑制。相反，Sr3(Mn(0.5)Ru(0.5))2O7和Sr3(Fe(0.5)Ru(0.5))2O7的氟化消除了氧化物相中存在的磁阻挫，导致在低温下观察到Sr3(Mn(0.5)Ru(0.5))2O7F2和Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5)中的长程反铁磁有序。基于钌氧化态的变化和结构畸变，讨论了拓扑化学氟化对Sr3(M(0.5)Ru(0.5))2O(x)F(y)相磁行为的影响。
