Materials Structure and Modeling Research Group of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary.
Inorg Chem. 2012 Jan 2;51(1):543-56. doi: 10.1021/ic202009v. Epub 2011 Dec 2.
The structures, energetic, and vibrational properties of MDyX(4) (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) mixed alkali halide/dysprosium halide complexes have been investigated by a joint computational and experimental, matrix-isolation Fourier-transform infrared spectroscopic (MI-IR), study. According to our DFT computations for the complexes with heavier halides and alkali metals the ground-state structure is the tridentate isomer; while at high temperatures the bidentate structural isomer dominates. The survey of various dissociation processes revealed the preference of the dissociation to neutral MX and DyX(3) fragments over ionic and radical dissociation products. Cationic complexes are considerably less stable at 1000 K than the neutral complexes, and they prefer to dissociate to M(+) + DyX(4)(•) fragments. The vapor species of selected mixtures of NaBr and CsBr with DyBr(3) and of CsI with DyI(3) in the temperature range 900-1000 K have been isolated in krypton and xenon matrices and investigated by infrared spectroscopy. Besides the characteristic vibrational frequencies of the monomeric and dimeric alkali halide species and of the dysprosium trihalide molecules, certain signals indicated the formation of MDyX(4) (M = Na, Cs; X = Br, I) mixed complexes. Comparison with the computed vibrational and thermodynamic characteristics of the relevant species lead to the conclusion that these complexes appear in the vapor predominantly as the C(2v)-symmetry bidentate isomer. This is the first time that this structure was identified in an experimental vibrational spectroscopic study. The signals appearing upon performing a thermal anneal cycle were tentatively assigned to the double complex M(2)DyX(5) (M = Na, Cs; X = Br, I). A structure in which one alkali atom is bound to dysprosium by three and the other by two bridges is proposed for these double complexes.
MDyX(4)（M = Li、Na、K、Rb、Cs；X = F、Cl、Br、I）混合碱金属卤化物/镝卤化物配合物的结构、能量和振动特性已通过联合计算和实验、基质隔离傅里叶变换红外光谱（MI-IR）研究进行了研究。根据我们对较重卤化物和碱金属配合物的 DFT 计算，基态结构为三齿异构体；而在高温下，双齿结构异构体占主导地位。对各种离解过程的调查表明，离解优先于中性 MX 和 DyX(3) 片段，而不是离子和自由基离解产物。在 1000 K 时，阳离子配合物的稳定性远低于中性配合物，它们更喜欢离解为 M(+) + DyX(4)(•)片段。在 900-1000 K 温度范围内，选择的 NaBr 和 CsBr 与 DyBr(3)以及 CsI 与 DyI(3)混合物的蒸汽物种已在氪和氙基质中分离出来，并通过红外光谱进行了研究。除了单体和二聚碱金属卤化物物种以及镝三卤化物分子的特征振动频率外，某些信号表明形成了 MDyX(4)（M = Na、Cs；X = Br、I）混合配合物。与相关物种的计算振动和热力学特性进行比较，得出的结论是这些配合物在蒸汽中主要以 C(2v)-对称双齿异构体的形式出现。这是首次在实验振动光谱研究中识别出这种结构。在执行热退火循环时出现的信号被暂时分配给双配合物 M(2)DyX(5)（M = Na、Cs；X = Br、I）。对于这些双配合物，提出了一种结构，其中一个碱金属原子通过三个桥与镝配位，另一个通过两个桥与镝配位。
