关键词: 氮杂环化合物, 分子轨道, 冠式化合物, 硝酸盐, Ｘ射线光电子谱法, 化学键, 电子结构, 铕络合物, 微分重叠间忽略近似

The electronic structure and bond character of europium nitrate complex with azacrown (2,2) (1,7,10,16-tetraoxa-4, 13-diazacyclooctadecane), [Eu(NO3)2(2,2)] NO3, have been studied by means of XPS and INDO method. The data of electronics binding energies and charge distribution of atoms in the complex showed that chem. shift of less electroneg. nitrogen N1s binding energy was larger than that of more electroneg. oxygen O1s binding energy in coordinating atoms, and that charge transfer from N to Eu occurred to a greater extent that that from O to Eu in the complex. It indicated that dative bonds of europium complex with azacrown possessed certain covalence in character, and that covalency of dative bond N瓻u was larger than that of bond O瓻u in the complex.

Key words: NITROGEN HETEROCYCLICS, MOLECULAR ORBIT, CROWN ETHER COMPOUNDS, NITRATE, X-RAY PHOTOELECTRON SPECTROMETRY, CHEMICAL BONDS, ELECTRONIC STRUCTURE, EUROPIUM COMPLEX, INTERMEDIATE NEGLECT OF DIFFERENTIAL OVERLAP APPROXIMATION (IND