线型异核三金属M－E－M（M＝Mo，W；E＝Hg，Zn）化合物的研究──［η~5－RC_5H_4（CO）_3M］_2Zn（M＝Mo，W；R＝CO_2Me，CO_2Et）的合成、性质及结构

Studies on Linear Heterotrimetallic M-E-M(M=Mo,W;E=Hg,Zn) Compounds──Synthesis,Properties and Structural Characterization of [η_5-RC_5H_4(CO)_3M]_2Zn(M=Mo,W;R=CO_2Me,CO_2Et)

研究了含汞三金属化合物［η_５－ＲＣ_５Ｈ_４（ＣＯ）_３Ｍ］_２Ｈｇ（Ｍ＝Ｍｏ，Ｗ；Ｒ＝Ｍｅ，Ｅｔ，ＣＯ_２Ｍｅ，ＣＯ_２Ｅｔ）与锌粉的置换反应，发现当取代基Ｒ为给电子的Ｍｅ和Ｅｔ时底物不发生反应，而取代基Ｒ为拉电子的ＣＯ_２Ｍｅ和ＣＯ_２Ｅｔ时，则底物中的汞可被锌置换，生成带有机官能团的三金属化合物［η_５－ＲＣ_５Ｈ_４（ＣＯ）_３Ｍ］_２Ｚｎ；另外，还发现Ｒ为ＣＯ_２Ｅｔ，Ｍ为Ｍｏ的产物［η_５－ＲＣ_５Ｈ_４（ＣＯ）_３Ｍ］_２Ｚｎ可在室温下被分解为相应的氯代物η_５－ＥｔＯ_２ＣＣ_５Ｈ_４ＭｏＣｌ．

The trimetallic M-Hg-M compounds containing an electron-withdrawing group R on cyclopentadienyl ring[η_5-RC_5H_4(CO)_3M]_2Hg (M=Mo,W;R=CO_2Me,CO_2Et) have been shown to react with activated Zn powder in THF at reflux to give the corresponding trimetallic M-Zn-M compounds [η_5-RC_5H_4(CO)_3M]_2Zn (M=Mo,W;R=Co_2Me,CO_2Et),while the M-Hg-M compounds carrying an electron-releasing substituent R on cyclopentadienyl ring [η_5-RC_5H_4(CO)_3M]_2Hg(M=Me, Et) failed to react with Zn powder under the similar conditions to afford the corresponding M-Zn-M compounds[η_5-RC_5H4(CO)_3M]_2Zn (M=Mo,W;R=Me,Et). These trimetallic compounds [η_5-RC_5H_4(CO) _3M]_2Zn (M=Mo,W;R=CO_2Me,CO_2Et)obtained are white and air-sensitive solids,soluble in high polar solvents such as THF,DMSO and.acetone,which have been fully char acterized by elementary analysis,IR,1H NMR and MS techniques. Interestingly,the com pound [η_5-RC_5H_4(CO)_3M]_2Zn(M=Mo,CO_2Et) was shown to react with CDCl_3 during 1H NMR determination to give the corresponding organometallic halide [η_5-EtO_2CC_5H_4·(CO)_3MoCl.