芳基汞化合物的性质研究(Ⅴ)——某些氯化芳基汞的质谱

STUDIES ON THE PROPERTIES OF ARYLMERCURIC COMPOUNDS (Ⅴ)——THE MASS SPECTRA OF SOME ARYLMERCU- RIC CHLORIDES

本文研究了23种氯化芳基汞XC_(6)H_(4)HgCl的质谱。结果证明大多数氯化芳基汞的分子离子峰均较强,且各种氯化芳基汞生成碎片离子D([XC_(6)H_(4)]^(+))均较汞—氯键断裂生成碎片离子E([XC_(6)H_(4)Hg]^(+))容易,此结果可以看作是汞有机化合物开裂的普遍性规律。 取代基的电性对于碎片离子的稳定性和丰度有明显的影响。就多数间、对位取代基而言,代表取代基对生成离子D速度的影响参数log Z/Z_(H)与HammettBrown常数σ^(+)之间有良好的线性关系。邻乙酯基苯基氯化汞与间、对位取代物比较,难于发生McLafferty重排,此与分子内配位有关。

The mass spectrometric behavior of 23 arylmercuric chlorides has been studied. The majority of compounds give intense peaks in the parent ion region. The fragmentation behavior observed for the molecular ions may be expressed as follows.■In was found that in every case studied formation of D is favored over cleavage of the mercuryhalogen bond which produced ion E. This result obtained in our investigation is consistent with that observed by other authors, and then may be considered as a generalized rule for the fragmentation of organomercurials.It has been shown that the electronic character of the substituents has pronounced effect on the stability and the abundance of the fragment ions. With respect to most of meta and para substituents the parameter, log(Z/Z_(H)), representing the substituent effect on the rate of formation of D ions, shows a good linear correlation with the Hammett-Brown constants σ^(+). In contrast with p- and m-ethoxycarbonyl-phenylmercuric chlorides, o-ethoxy-carbonyl-phenylmercuric chloride undergoes the McLafferty rearrangement more difficultly and this feature is probably associated with the intramolecular coordination which exists in the molecule of o-ethoxycarbonyl-phenylmercuric chloride.