异核过渡金属类立方烷原子簇化合物M_3S_4L_9M'X~(n+)的电子结构

本文利用定性价键理论、半经验分子轨道法和分子轨道碎片法,讨论了通式为M_3S_4L_9M′X~(n+)(M=Cr,Mo,W;M′=Fe,Co,Ni,Cu;n=0,4,5)的异核过渡金属簇合物Cr_3S_4Cp_3FeOOCCMe_3(1),Cr_3S_4Cp_3CoCO(2),Mo_3S_4(NH_3)_9FeOH_2~(4+)(3)和Mo_3S_4(OH_2)_9NiOH_2~(4+)(4)的电子结构,成键性质,以及活性元件(碎片)L_9M_3S_4~(n+)和M′X组装的合理性。指出了由于碎片组装成类立方烷后,电子从M′原子转移到M原子,使得过渡金属原子M的氧化态低于不完整类立方烷中的M原子。此外,本文还根据价键理论和分子轨道法的集居数分析,给出簇合物骨架的相对稳定性顺序是Mo_3S_4FC~(4+)>Cr_3S_4Fe~(4+)>Cr_3S_4Co~(4+)>Mo_3S_4Ni~(4+)。

Electronic Structure in Heterometallic Cubane-Type Cluster M_3S_4L_9M'X~(n+) (M=Cr,Mo,W;M' =Fe,Co,Ni,Cu; L(X) =terminal ligand;n= 0,4,5)

The electronic structures and bonding properties have been reported for Cr3S4Cp3FeO2CCMe3 (1) , Cr3S4Cp3CoCO(2),Mo3S4(NH3)9FeOH24+(3) and Mo3S4(OH2)9NiOH|+(4) in terms of SCCC-EH Mo calculations and fragment MO analyses. It has been found that the formal oxidation state of M atom is lower in M3S4M'n+(M = Cr,Mo, W;M'=Fe,Co,Ni,Cu;n= 0, 4, 5) than in M3S4n+ because of transference of electrons from M' to M atom in completed cuban-like cluster skeleton. Moreover,a se-quance of the relative strengths decreasing of fragment interactions between the heterometallic atoms were gave in the order Fe -Mo3>Fe -Cr3>Co -Cr3>Ni -Mo3 based on the Mulliken reduced fragment overlap population analyses.