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化学学报
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化学学报 ›› 1992, Vol. 50 ›› Issue (7): 661-667. 上一篇    下一篇

研究论文

担载四核羰基簇:FeCo~3(CO)~11PPh 在聚苯乙烯表面簇骼畸变的EXAFS研究

卢建军;寇元;罗玉忠;李红兵;傅宏祥;殷元骐   

  1. 中国科学院兰州化学物理研究所;中国科学院上海有机化学研究所
  • 发布日期:1992-07-15

Immobilized detranuclear carbonyl cluster:EXAFS investigation on the framework distortion of FeCoo~3(CO)~11PPh on the surface of polystyrene

LU JIANJUN;KOU YUAN;LUO YUZHONG;LI HONGBING;FU HONGXIANG;YIN YUANQI   

  • Published:1992-07-15

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通过配体取人工将四核羰基簇FeCo~3(CO) 锚联在膦化的聚苯乙烯表面,获得担载簇FeCO~3(CO)~11PPh/poly,目的在于使簇骼结构偏离较高对称性,以考察锚联过程对簇结构的影响.本文以EXAFS(Extended x-ray Absorption Fine Struature)方法研究了担载样品的结构.结果显示担载簇与FeCO~3(CO)~11PPh 晶体具有相同的结构模式,尤其是膦配体确实与一Co原子相连接.EXAFS结果表明:(1)与FeCO~3(CO) (其簇骼具有三重对称结构)比较,锚联使Co-Fe键增长0.005nm;金属-金属及金属-桥联碳壳层Debye-Waller因子均增大约一倍而金属一端联碳壳层的值变化很小.说明金属-金属间实际键长值具有一较宽分布,因而其簇骼已偏离了三重对称结构;(2)与FeCO~3(CO)~11PPh 晶体的结构比较,Co-Fe键长长0.003nm而Co-Co键长则短约0.002nm.考虑到EXAFS分析只能给出平均键长值,因此认为,存在于FeCO~3(CO)~11PPh 晶体中的由于一个羰基被膦配体取代而引起的簇骼畸变,在锚联后被加剧.

关键词: 聚苯乙烯, 铁络合物, 羰基化合物, 三苯基膦, 钴络合物, EXAFS

The aim of anchoring the cobalt-iron tetranuclear carbonyl cluster FeCo3(CO)12- on the phosphinated surface of the polystyrene through ligand substitution was to obtain the cluster FeCo3(CO)11PPh3-/poly. The structural model of the mol. studied was the same as in the FeCo3(CO)11PPh3- crystal: the phosphine ligand was indeed bonded to one Co atom. In comparison with those of FeCo3(CO)12-, the structure has a three-fold symmetry. The bond length Co-Fe was longer by 0.005 nm. The Debye-Waller factors of the M-M and M-C(b) (M = metal; C(b) = bridging carbon) shells were about two times greater, but that of C(t) (C(t) = terminal carbon) shell, remained almost the same. In comparison with the FeCo3(CO)11PPh3- structure, the Co-Fe bond length was 0.003 nm longer, and the Co-Co bond length was 0.0 (2 nm shorter. The distortion of FeCo3(CO)11PPh3- is caused by substituting one CO by PPh3.

Key words: POLYSTYRENE, IRON COMPLEX, CARBONYL COMPOUNDS, TRIPHENYLPHOSPHINE, COBALT COMPLEX

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