Stabilization of SF5- with Glyme-Coordinated Alkali Metal Cations
Stabilization of SF5- with Glyme-Coordinated Alkali Metal Cations
复制标题
用甘醇二甲醚配位碱金属阳离子稳定 SF5-
DOI：
10.1021/acs.inorgchem.8b02655
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发表时间：
2018
影响因子：
4.6
通讯作者：
Rika Hagiwara
中科院分区：
文献类型：
--
作者：
Kazuhiko Matsumoto;Yuki Haruki;Shunsuke Sawada;Shigeyuki Yamada;Tsutomu Konno;Rika Hagiwara
弱酸性母体氟化物衍生的复合氟阴离子的稳定是一项重大而持续的挑战。[SF₅]⁻被认为是一个这样的例子，只有有限数量的[SF₅]⁻在室温下是稳定的。在本研究中，使用碱金属配位阳离子（K +， Rb +和Cs +）来稳定[SF₅]⁻，这为[SF₅]⁻提供了一个简单的合成途径。拉曼光谱分析表明，与G4络合后，KF和RbF与硫酸钠的反应活性明显增强。通过CsF、G4和硫酸铵的化学计量反应，合成了一种新的室温稳定盐[Cs （G4）₂][SF₅]（G4=四甲酰胺）。根据量子化学计算确定了[SF₅]的振动频率，并通过拉曼光谱证实了G4呼吸模式伴随配位到金属阳离子的转变。单晶x射线衍射显示，Cs⁺与[SF₅]两个G4配体完全分离，并且[SF₅]在结晶双轴上是无序的。Hirshfeld表面分析显示，两个相邻的[Cs (G4) 2] +部分之间的H··H相互作用在Hirshfeld表面上比[SF₅]中H原子和F原子之间的相互作用更占优势，提供了一个csc型的结构模型，其中大而球形的[Cs (G4) 2] +阳离子相互接触，[SF₅]⁻占据了晶格中的间隙空间。[SF₅]⁻+ [Cs (G4) 2]⁺在整齐条件和四氢呋喃溶液中都表现出非常有限的对羟基的脱氧氟化能力。
The stabilization of complex fluoroanions derived from weakly acidic parent fluorides is a significant and ongoing challenge. The [SF₅]⁻ anion is recognized as one such case, and only a limited number of [SF₅]⁻ salts are known to be stable at room temperature. In the present study, glyme-coordinated alkali metal cations (K⁺, Rb⁺, and Cs⁺) are employed to stabilize [SF₅]⁻, which provides a simple synthetic route to a [SF₅]⁻ salt. The reactivities of KF and RbF with SF₄ are significantly enhanced by complexation with G4, based on Raman spectroscopic analyses. A new room-temperature stable salt,[Cs (G4) ₂][SF₅](G4= tetraglyme), was synthesized by stoichiometric reaction of CsF, G4, and SF₄. The vibrational frequencies of [SF₅]⁻ were assigned based on quantum chemical calculations, and the shift of the G4 breathing mode accompanying coordination to metal cations was confirmed by Raman spectroscopy. Single-crystal X-ray diffraction revealed that Cs⁺ is completely isolated from [SF₅]⁻ by two G4 ligands and [SF₅]⁻ is disordered along the crystallographic two-fold axis. Hirshfeld surface analysis reveals that the H··· H interaction between two neighboring [Cs (G4) ₂]⁺ moieties is more dominant on the Hirshfeld surface than the interaction between the H atom in glyme molecules and the F atom in [SF₅]⁻, providing a CsCl-type structural model where the large and spherical [Cs (G4) ₂]⁺ cations contact each other and the [SF₅]⁻ anions occupy interstitial spaces in the crystal lattice. The [SF₅]⁻ anion, combined with [Cs (G4) ₂]⁺, exhibits a very limited deoxofluorinating ability toward hydroxyl groups in both neat conditions and THF solutions.