5-クロロ-7-ハロゲノオキシンニッケル(II)キレートの質量分析

金属キレートの質量分析法(第6報)

抄録

In order to examine the effect of the substituting groups in the mass spectrometry of divalent metal oxinates, nickel (II) chelates of 5-chloro-7-halogenooxine (halogens : chlorine, bromine and iodine) were studied.
Measurements were made with a Hitachi double focus mass spectrometer RMU-7, by means of the direct inlet system. The conditions are: ionization voltage 70 eV, ion accelerating voltage 1800 V, total emission current 80 μA and ion source temperature 250 °C.
The ligands, 5-chloro-7-halogenooxine, show two fragmentation processes: (1) removal of CO from the molecular ion, followed by the loss of the halogen radical at 7-position, and (2) removal of the halogen radical at 7-position, followed by the loss of CO and the halogen radical at 5-position. Every nickel chelate loses one ligand radical from a 2:1 molecular ion to give 1:1 fragment ion. However, nickel chelates of 5-chloro-7-bromo- and 5-chloro-7-iodooxine were observed to lose bromine or iodine radical, while this phenomenon was not observed with 5, 7-dichlorooxine nickel chelate. The fragment ion derived from the 1:1 fragment ion by the loss of CO released the chlorine radical firstly to give 5-chlorooxine. However, 7-iodooxine lost the iodine radical firstly and then nickel was removed. In bromooxine, both fragmentation processes were observed simultaneously.