【摘要】 本文总结了作者研究的一组合有羧基的三核钼原子簇的结果。这些簇合物分为两类。第一类有: （C₂H₅）₄N[Mo₃（μ₃-O）（μ-O₂CH）₃（μ-Cl）₃Cl₃] （Ⅰ） （CH₃）₄N[Mo₃（μ₃-O）（μ-O₂CH）₃（μ-Cl）₃Cl₃] （Ⅱ） （CH₃）₄N[Mo₃（μ₃-O）（μ-O₂CH）₃（μ-Br）₃Cl₃] （Ⅲ） （C₅H₇S₂）[Mo₃（μ₃-O）（μ-O₂CCH₃）₃（μ-Cl）₃Cl₃] （Ⅳ） （C₅H₇S₂）[Mo₃（μ₃-O）（μ-O₂CCH₃）₃（μ-Br）₃Cl₃] （Ⅴ） （C₂H₅）₄N[Mo₃（μ₃-O）（μ-O₃CCH₃）（μ-Cl）₃X₃] （Ⅵ） （X为Cl和Br统计分布的簇合物） （C₂H₅）₄N[Mo₃（μ₃-O）（μ-O₂CCH₂CH₃）₃（μ-Cl）₃Cl₃] （Ⅶ） （C₂H₅）₄N[Mo₃（μ-O）（μ-O₂CCH₂CH₂CH₃）₃（μ-Cl）₃Cl₃] （Ⅷ） （Ⅰ）-（Ⅷ）的簇阴离子具有下述通式: [Mo₃（μ₃-O）（μ-O₂CR）₃（μ-X）₃X₃^′]^-; R=H,CH₃,CH₃CH₃,CH₂CH₂CH₂:X和X′=Cl或Br。 属于第二类型的目前只有一个,即: [（C₂H₅）₄N]₂[Mo₃（μ₃-O）（μ-O₂CCH₃）₂（μ-Cl）₃Cl₅) （Ⅸ） 本文将扼要介绍这些簇合物的合成方法,晶体和分子结构的主要特征,并对成簇规律、结构变化规律以及μ₃-O的红外光谱的指认,给予简单的讨论。更多还原

【Abstract】 In this paper, a series of trinudear molybdenum clusters containing carboxylic ligands is summarized. These clusters can be classified into two types. In the first type there are eight clusters,(CH3)4N[Mo3(u3,-O)(u-O2CH)3(u-Br)3Cl3] (III)(C5H7S2)[Mo3(u3-O)(u-O2CCH3)3(u-Cl)3Cl33 (IV)(C5H7S2)[Mo3(u3-O)(u-O2CCH3)3(u-Br)3Cl3] (V)(X = statistically distributed Cl and Br atoms)(C2H5)4N[Mo3(u3-O)(u-O2CCH3)3(u-Br)3Cl3] (VII)Cluster anions (I)-(VIII) may be formulated as CMo3(u3-O)(u-O2CR)3(u-X)3X’3]-, where R=H, CH3, CH3CH2, CH3CH2CH2; X and X’ = Cl or Br. In the second type there is one cluster:(C2H5)4N[Mo3(u3-O)(u-O2CCH3)2(u-Cl3)Cl5] (IX)The general synthetic procedure is to react hydrates of tervalent molybdenum chloride or bromide with carboxylic acids or mixtures of carboxylic acids and carboxylic anhydrides.All of these clusters have a triangular Mo3 cluster core with Mo-Mo distances of about 2.6A. A capping oxygen atom is located on one side of the triangle and three doubly bridging halogen atoms on the other to form an apex-deficient quasicubane configuration. Besides, there are two or three bridging carboxylic radicals bondsd to Mo atoms through their oxygen atoms to form planar "Mo2O2C" five-membered rings and to complete an octahedral coordination around each Mo atom together with additional terminal halogen atoms. No chelating "MoO2C" ring has been observed in these clusters.Tririuclear Mo cluster cores are proposed to form first based on the retaintion for the bridging halogen atoms from the halogen exchange experiments.A comparatively strong absorption band around 700cm"1 is assigned to an Mo3-u3-O characteristic vibration and a higher wave number is found to correspond essentially to a shorter average Mo-Mo bond length.Several other structural chemistry features of these clusters are also presented and discussed briefly. Clusters with 8 cluster core electrons have a deeper colour than those of 6 electrons, Neither cation, nor exchange of carboxylic acids shows an appreciable effect on the Mo-Mo bond lengths. Substitution of bridging Br atoms for Cl atoms or, replacement of one bridging O2CR radical by two terminal Cl atoms increase the Mo-Mo bond length by about 0.02A. Adding one electron to bonding Mo3 core orbital would shorten the Mo-Mo length by about 0.07-010A.更多还原