含硫氮杂环卡宾铁羰基簇合物的合成和结构

Fe~3(CO)~1~2与4个S,N取代的杂环硫代酰胺配前体SCSC(SR)NNPh(SL~n),其中SL~1:R=Me;SL~2:R=Et;SL~3:R=n-Pr;SL~4:R=i-Bu]反应,合成得到含硫氮杂环卡宾配体的通式为Fe~3(CO)~8(μ~3-S)~2L]的4个新羰合铁簇合物(1～4)。其配体S原子和杂环卡宾L皆来自配前体SL的劈开。对它们进行了元素分析,IR,^1HNMR和MS表征,并用X射线衍射测定了2的晶体分子结构,表明含硫氮杂环分子片CSC(SR)NNPh(L)的卡宾碳具有sp^2成键特征,其C~卡~宾键长为0.1960nm。2的分子几何构型维持母体物Fe~3(CO)~9(μ~3-S)~2]的形状,其中卡宾基取代四方锥分子骨架Fe~3S~2基底平面Fe(1)S(1)Fe(3)S(2)的Fe(3)原子上径向位置的一个端羰基CO。

Synthesis and structures of trinuclear iron carbonyl clusters with S, N-containing heterocyclic carbene ligands

The reaction of Fe~3(CO)~1~2] with four S, N-substituted heterocyclic thioamides SCSC(SR)NNPh(SL~n, where SL~1:R=Me; SL~2: R=ET; SL~3:R=n-pr; SL~4:R=i-Bu)] yields new open triangelar iron carbonyl clusters Fe~3(CO)~3(μ~3-S)~2L] 1～4. It was found that the coordinated ligands in the product clusters were two sulfito S atoms and a heterocyclic carbene L which was formed from the cleavage of the ligand precursor SL~n. The formulas and structures of these clusters were characterized by elemental analysis, IR, ^1H NMR, and MS techniques and the molecular structures of 2 was determined by X- ray diffraction analysis. The sp^2 bonding character of the carbon (carbene) atom of fragmental S, N-substituted heterocyclic thioamides CSC(SEt)NNPh(L~2) is showed clearly in 2 and the C~c~a~r~b~e~n~e-Fe bond length of 0.1960nm corresponds to other iron stabilized carbenes. This carbene ligand displaces a terminal radial CO of the basal Fe(3) atom and locates in an essentially coplanar position to the Fe(1)S(1) Fe(3)S(2) distorted basal plane. The open triangular geometry of the matrix cluster Fe~3(CO)~9(μ~3-S)~2] with a distorted Fe~3S~2 square pyramidal framework has been maintained in 2.