Two chlorinated aromatic imine derivatives of hexamolybdate,TBA2[Mo6O18(N-C6H4-Cl-p)](TBA=Tetrabutylamine)(Ⅰ)and TBA2[Mo6O18(N-C6H4-Cl-o)](Ⅱ)were synthesized and characterized using electrospray ionization mass spectrometry(ESI-MS)via the collision induced dissociation(CID)gas phase cracking pathway.ESI-MS results showed that the main existence form of two derivatives in solution are bare polyanion[Mo6O18(N-C6H4-Cl)]2-and a small number of single charge addition anion clusters of[HMo6O18(N-C6H4-Cl)]-and[(TBA)Mo6O18(N-C6H4-Cl)]-by H+and TBA+.The CID results indicated that the multiple Mo—O bonds on polyoxometalate(POM)framework were broken to generate low nuclearity molybdate fragments that retain the organic component under N2 collision,while the corresponding low-nuclearity molybdate fragment was also generated at the same time so that these daughter ions were further broken to form a new generation of daughter ions with lower nuclear numbers(secondary mass spectrometry(MS/MS)diagram).The abundance of daughter ions containing organic component aromatic imine compound Ⅱ is lower than that of imine compound Ⅰ,due to the lower stability of Mo=N in compound Ⅱ ions,which is consistent with its optimal collision energy being less than compound Ⅰ.This study established ESI-MS fingerprints of compounds Ⅰ and Ⅱ,further expanding the structural characterization library of these organic functionalized polyoxometalates.
关键词
电喷雾电离质谱法/六钼酸盐的芳香亚胺衍生物/碰撞诱导解离(CID)/指纹图谱
Key words
electrospray ionization mass spectrometry/aromatic imine derivatives of hexamolybdate/collision induced dissociation(CID)/fingerprint
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