VO(Ⅱ)-π受体配合物的结构及其ESR波谱研究

The Studies on the Structures and ESR Spectra of Oxovanadium Complexes with π-Acceptor Ligands

本文考察了VOSO_4与α,α′-联吡啶,3,4,7,8-四甲基-1,10-邻菲罗啉和1,10-邻菲啰啉在不同酸度(pH=1—14)的乙二醇-水(1:1)溶液中,低温下的ESR波谱.发现当pH<1.0时A=118×10^(-4)T,归属于[VO(H_2O)_5]^(2+);当pH>11时A=90×10^(-4)T,归属于[VO(OCH_2CH_2O)_2]^(2-).1.0<pH<7之间VO(II)与三种配体分别生成四种或三种不同的配合物,本文推测了它们的可能结构.利用测得的波谱参数,计算了键参数和电子能级.发现键参数的值随溶液pH值增加而减少,电子能级数据与实验结果相吻合.利用电子光谱数据还计算了VO(phen)_2^(2+)的晶体场参数.

The ESR spectra of oxovanadium complexes with α, α'-bipyridine, 3, 4, 7, 8-tetramethyl-1, 10-phenanthroline and 1, 10-phenanthroline in glycol water (1:1) solution at various acidity (pH =1-14) have been observed at 77K. It is found that when pH<1.0 A = 118×10^(-4)T is attributed to the complex[VO(H_2O)_5]^(2+); when pH>11 A=90xl0^(-4)T is attributed to the bidentate chelate of glycol[VO(OCH_2CH_2O)_2]^(2-) and that within the range of 1.0<pH<7.0 the three ligands can coordinate with oxovanadium to form four or three complexes, respectively. Their possible structures were suggested in this paper. The bonding parameters and electronic energy levels were calculated using the spectral parameters measured. It is found that the values of bonding parameters decrease with the increasing pH values of the solution. The data of electronic energy levels agree fairly well with the experimental results. The crystal field parameters of VO(phen)_2^(2+) complex were also calculated using the electron spectrum data.