若干新型亚硝基钼硫化合物的结构特征

本文总结了若干亚硝基钼硫络合物——(CH_3)_4N]_2KMo_2O(S_2)_3S_5-(NO)_2]·H_2O(Ⅰ),Na_2Mo_4O(S_2)_6(NO)_4]·3H_2O(Ⅱ),(CH_3)_4N]_2-NaMo_2O(S_2)_3S_5(NO)_2]·H_2O(Ⅲ)的结构特征。化合物(Ⅰ)和(Ⅲ)系具有相同的亚硝基钼硫阴离子的新构型化合物,其晶体分属于不同空间群。在这三个化合物中Mo原子均为畸变的五角双锥配位构型,即由5个S原子组成五角双锥的赤道面,一个桥基氧和一个NO基则分别位于五角双锥轴线上的两端。三个结构中Mo原子均通过硫桥和氧桥形成二聚或四聚。硫的配位方式显示出多样性。此外,比较三个结构,说明了Na~+,K~+阳离子对阴离子对称性的影响。

Structural Features of Some New Types of Nitrosyl Molybdenum-Sulphur Compounds

The structural features of three nitrosyl-molybdenum-sulphur complexes(CH3)N]2KMo2O(S2)3S5(NO)2]·H2O (I), Na2Mo4O(S2)6(NO)4]·3H2O (II), (CH3)4-N)2NaMo2O(S2)3S5(NO)2]·H2O(III) are summarized in this paper. (I) and (III) are new type nitrosyl-molybdenum-sulphur compounds with anions possessing similar molecular configurations although the crystals belong to different space groups. On the other hand, the anion in (II) has the same molecular configuration as those found in (NH4)2Mo4(NO)4(S2)6O]·2H2O and (NH4)KMo4-(NO)4 S2)6O]·2H2O whereas the synthetic methods and the cations of them are different. Each molybdenum atom in these three complexes has a distorted pentagonal bipyramidal configuration with a linear NO and a bridging 0 in the axial position and five S atoms in the equatorial position. Moreover, the anion of (II) can be considered as the result of dimerization of the anions in (I) or (III). It is interesting to note that there are several different coordination modes for the sulphur ligands. Meanwhile, the differences in the crystal structures of identical anions can probably be attributed to the difference in cation sizes and their effects on the packing of the bulky anions in the crystals.