论文部分内容阅读
本文采用红外光谱、紫外漫反射光谱、穆斯堡尔谱和程序升温分解等方法研究了担载的(π—C_5H_5)_2Fe_2(CO)_4(Ⅰ)及C_(10)H_(15)N[FeCo_3(CO)_(12)](Ⅱ)络合物的表面模型及脱羰基过程。实验结果表明,络合物(Ⅰ)担载于Al_2O_3上时,其端羰基的红外振频带向高波数位移,而桥羰基的振频带却向低波数方向位移。紫外光谱表明,担载后络合物的结构没发生明显变化,络合物中的羰基在真空中随温度的升高逐渐脱去。络合物(Ⅰ)担载于ZrO_2上时其性质与以Al_2O_3为载体时相似,但红外振频带位移较小。这两种表面络合物脱羰基后均以Fe~(+++)的的型式存在于载体表面上。担载于Al_2O_3上的表面络合物(Ⅱ),在真空中脱羰基时,端羰基比桥羰基易于脱去,且前者可部分转化为后者。在CO气氛中脱羰基时,端羰基与桥羰基同时脱去,脱羰基后的样品以Fe~(+++)及Co~(++)的型式存在于Al_3O_3表面上。根据实验结果提出了担载络合物可能的结构模型,并讨论了表面络合物的分解机理。
In this paper, the effects of (π-C_5H_5) _2Fe_2 (CO) _4 (Ⅰ) and C_ (10) H_ (15) N [ FeCo_3 (CO) _ (12)] (Ⅱ) Complexes and Their Decarbonylation Processes. The experimental results show that when the complex (Ⅰ) is supported on Al 2 O 3, the infrared vibrational band of terminal carbonyl shifts to a higher wave number, while the vibrational band of bridge carbonyl shifts to a lower wave number. UV spectroscopy showed that there was no obvious change in the structure of the complex after loading. The carbonyl group in the complex was gradually removed with the increase of temperature in vacuum. When the complex (Ⅰ) is supported on ZrO 2, its properties are similar to that of Al 2 O 3 as carrier, but the displacement of infrared vibration band is small. After decarbonylation, both surface complexes exist in the form of Fe ~ (+++) on the carrier surface. When the surface complex (II) supported on Al 2 O 3 is decarbonylated in vacuum, the terminal carbonyl group is easier to be removed than the bridge carbonyl group, and the former can be partially converted into the latter. When decarbonylation in CO atmosphere, the terminal carbonyl group is removed simultaneously with the bridge carbonyl group, and the decarbonyl group is present on the surface of Al 3 O 3 with Fe ~ (+++) and Co ~ (++). Based on the experimental results, a possible structural model of the supported complex was proposed and the mechanism of the decomposition of the surface complex was discussed.