Reactions with oleum under harsh conditions: characterization of the unique [M(S2O7)3]2- ions (M=Si, Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag).
Reactions with oleum under harsh conditions: characterization of the unique [M(S2O7)3]2- ions (M=Si, Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag).
复制标题
恶劣条件下与发烟硫酸的反应：A2[M(S2O7)3] (A=NH4, Ag) 中独特的 [M(S2O7)3]2- 离子 (M=Si, Ge, Sn) 的表征。
作者：
C. Logemann;Daniel Gunzelmann;T. Klüner;J. Senker;M. Wickleder
第14族四氯化物MCl（4）（M=Si，Ge，Sn）与SO2（65%SO（3））在高温下反应生成独特的配离子[M（S（2）O（7））（3）]（2-），其中心M原子与三个螯合S（2）O（7）（2-）基团配位。阴离子间的平均距离从175.6（2）-177.5（2）pm（M=Si）增加到186.4（4）-187.7（4）pm（M=Ge）和201.9（2）-203.5（2）pm（M=Sn）。这些距离被DFT计算很好地再现。同样的计算表明，在Si，Ge，Sn行中的中心M原子的正电荷增加，这可以解释为M-O键的共价性降低。对于硅化合物（NH（4））（2）[Si（S（2）O（7））（3）]，进行了（29）Si固态NMR测量，结果显示（NH（4））（2）[Si（S（2）O（7））（3）]在-215.5 ppm处的信号，这与理论估计非常一致。此外，[MO（6）]骨架内的振动模式已被监测的拉曼光谱的选定的例子，并很好地再现了理论。[M（S（2）O（7））（3）]（2-）离子的电荷平衡通过单价A（+）抗衡离子（A=NH（4），Ag）实现，其在合成中以其硫酸盐的形式实现。A（+）离子的大小，即它们的配位要求，导致晶体结构中的晶体学差异，尽管络合物[M（S（2）O（7））（3）]（2-）离子基本上不受不同A（+）离子的影响。此外，A（+）离子的性质影响化合物的热行为，这已经通过热重差热分析（DTA/TG）和XRD测量对所选实施例进行了监测。
The reactions of group 14 tetrachlorides MCl(4) (M=Si, Ge, Sn) with oleum (65% SO(3)) at elevated temperatures lead to the unique complex ions [M(S(2)O(7))(3)](2-), which show the central M atoms in coordination with three chelating S(2)O(7)(2-) groups. The mean distances M-O within the anions increase from 175.6(2)-177.5(2) pm (M=Si) to 186.4(4)-187.7(4) pm (M=Ge) to 201.9(2)-203.5(2) pm (M=Sn). These distances are reproduced well by DFT calculations. The same calculations show an increasing positive charge for the central M atom in the row Si, Ge, Sn, which can be interpreted as the decreasing covalency of the M-O bonds. For the silicon compound (NH(4))(2)[Si(S(2)O(7))(3)], (29)Si solid-state NMR measurements have been performed, with the results showing a signal at -215.5 ppm for (NH(4))(2)[Si(S(2)O(7))(3)], which is in very good agreement with theoretical estimations. In addition, the vibrational modes within the [MO(6)] skeleton have been monitored by Raman spectroscopy for selected examples, and are well reproduced by theory. The charge balance for the [M(S(2)O(7))(3)](2-) ions is achieved by monovalent A(+) counter ions (A=NH(4), Ag), which are implemented in the syntheses in the form of their sulfates. The sizes of the A(+) ions, that is, their coordination requirements, cause the crystallographic differences in the crystal structures, although the complex [M(S(2)O(7))(3)](2-) ions remain essentially unaffected with the different A(+) ions. Furthermore, the nature of the A(+) ions influences the thermal behavior of the compounds, which has been monitored for selected examples by thermogravimetric differential thermal analysis (DTA/TG) and XRD measurements.