系列异金属类立方烷原子簇化合物的振动光谱

Vibrational Spectroscopic Investigation of a Series of Heterometallic Cubane-like M′—Mo(W) Cluster Compounds

通过振动光谱和X 射线结构分析数据的结合 ,归属了系列具有 [M3 YS3 M′](M =Mo ,W ;Y =O ,S ;M′=Cu ,Sn ,Sb ,Pb ,Bi)簇芯的异金属四核类立方烷原子簇化合物的主要振动谱峰。讨论了五种结构类型的光谱特征和成键状态。M′的加入使νM— (μ3—Y) 和νM S 频率下降。当M′为过渡金属 ,例如Cu时 ,Cu与[M3 YS3 ]结合紧密造成了与Cu—S共价键相当的νCu—S振动频率。而当M′为主族金属时 ,νM′—S远小于相应共价键的振动频率值。文中还对νM—M 振动进行若干论述。

By combining the results of IR spectroscopic experiments with the molecular structures,the main stretching vibrations of a series of the heterometallic tetranuclear cluster compounds with [M 3YS 3M′] cluster core (M=Mo,W;Y=O,S;M′=Cu,Sn,Pb,Sb,Bi) have been assigned.The characteristic features and the bonding situations of the five configuration types are discussed.It is shown from the IR and Raman spectra that when M′ is a transition metal such as Cu,the ν M′ S frequency of the [M 3YS 3M′] core has a value comparable to that of corresponding M′—S covalent bond thus indicating a close combination of M′ with [M 3YS 3].Whereas when M′ is a main group metal,the ν M′—S vibration is always observed in a lower region than of the M′—S covalent bond because of a loose combination of M′ with[M 3YS 3].However,remarkable enhancement of M—M band strength due to the addition of M′ is demonstrated by Raman spectra.Some comments for the M—M vibration of various structures of these compounds are also described.