Jagiellonian University, Faculty of Chemistry, Department of Chemical Physics, No. 3, Ingardena Street, 30-060 Kraków, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Sep;79(5):1179-86. doi: 10.1016/j.saa.2011.04.039. Epub 2011 May 18.
Single crystal X-ray diffraction studies of Mn(OS(CH3)2)62 have shown that the low temperature phase transition, detected by differential scanning calorimetry (DSC) at about 223 K, is associated with the crystal symmetry's reduction from an orthorhombic crystallographic system (Fdd2, No. 43) to a monoclinic one (Cc, No. 9). The analysis of the full width at half maximum of the bands connected with: δd(OClO)F2 and ρ(CH3) vibrational modes in the FT-IR and FT-RS spectra, respectively, registered in the function of temperature, proved that the reorientational motions of ClO4- anions and CH3 groups from (CH3)2SO ligands, began to slow down at temperatures below the phase transition at about 223K. Mean values of activation energy for ClO4- reorientation in the high temperature phase I and low temperature phase II are: Ea(I)≈14 kJ mol(-1) and Ea(II)≈10 kJ mol(-1), respectively. Analogous values for CH3 reorientation are: Ea(I)≈23 kJ mol(-1) and Ea(II)≈1 kJ mol(-1), respectively.
单晶 X 射线衍射研究表明，Mn(OS(CH3)2)62 在约 223 K 时通过差示扫描量热法 (DSC) 检测到的低温相转变与晶体对称性从正交晶系 (Fdd2，No. 43) 降低到单斜晶系 (Cc，No. 9)有关。对 FT-IR 和 FT-RS 光谱中分别与 δd(OClO)F2 和 ρ(CH3)振动模式相关的带宽的半峰全宽的分析表明，ClO4-阴离子和 CH3 基团从 (CH3)2SO 配体的重新取向运动在约 223 K 的相变温度以下开始减缓。高温相 I 和低温相 II 中 ClO4-重排的活化能平均值分别为：Ea(I)≈14 kJ mol(-1)和 Ea(II)≈10 kJ mol(-1)。CH3 重排的类似值分别为：Ea(I)≈23 kJ mol(-1)和 Ea(II)≈1 kJ mol(-1)。
