三核钼原子簇化合物研究Mo3(μ3-O)(μ-S2)3[S2P(OEt)2]3Cl的合成、晶体与分子结构

本文研究的钼簇合物晶体呈橙黄色菱形片状, 属单斜晶系。晶胞参数: a=0.8253(5), b=2.1018(10), c=2.1531(17) nm, β=90.89(6)(°), V=3.734(7) nm, z=4, D_c=1.934 g·cm~3。晶体空问群为P2_1/n。晶体结构通过直接法和Fourier合成法解出, 偏离因子R=0.061。结果表明, 晶体系由兰核钼簇中性分子所组成, 分子中三重桥氧将呈等边三角形的三核钼联结起来, 每两个钼原子之间还有一个双硫基团作为二重桥, 其中一个S原子基本上与三核钼共面, 另一个处在平面外与三重桥氧相对的另一侧, 此外每个钼原子还由一个S_2P(DEt)2]~-基团中的两个S原予补充端基配位, 使钼原予的局部配位接近于五角双锥。另外, 有一个氯原子将位于Mo_3]平面外的三个S原子联结, S-Cl之间有微弱成键作用。

RESEARCH ON THE TRINUCLEAR MOLYBDENUM CLUSTERS SYNTHESIS CRYSTAL AND MOLECULAR STRUCTURE OF Mo3(μ3-O)(μ-S2)3[S2P(OEt)2]3Cl

The title crystal is yellow in collour,belonging to the monoolinic system.The space group is P_(2_1)/n with following unit cell parameters: a=0.8253(5), b=2.1018(10), c=2.1531(17) nm; β=90.89(6)(°), V=3.734 (7) nm, Z=4. D_calc=1.934 gcm~(-3). The crystal structure was solved by the direct method(MULTAN-82)and refined by full-matrix least-squares to a final conventional R factor of 0.061. The results reveal that the crystal structure consists of neutral trinuclear Mo cluster molecules, in which three independent Mo atoms form an equilateral triangle with an average side length of 0.2631 nm, corresponding to a Mo-Mo single bond. On one side of the triangle one μ_3-S atom binds the three Mo atoms together to form a monocapped trinuclear cluster. In addition, three S_2 radicals acting as μ_2 bridges are located between each two Mo atoms. Each Mo atom is also coordinated by two terminal S atoms of S_2P(OEt)_2]~- radical so as to complete a distored pentagonal bipyramid configuration.