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Scorpionate complexes of aza‐18‐crown‐6 containing fluoronitrophenyl substituents as studied by electrospray ionization mass spectrometry
Author(s) -
Frański Rafał,
Onyszkiewicz Magdalena,
Gierczyk Błażej
Publication year - 2017
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7908
Subject(s) - chemistry , electrospray ionization , mass spectrometry , extractive electrospray ionization , electrospray mass spectrometry , electrospray , ionization , crown (dentistry) , chromatography , protein mass spectrometry , organic chemistry , ion , medicine , dentistry
Rationale Coordination of a metal cation by a nitro group is rare and the interaction between them is usually weak. Examples of complexes in which such an interaction takes place are metal complexes of cyclams containing nitrophenyl or nitrobenzyl substituents. It seemed to be interesting to check if in the complexes of the respective crown ether conjugates the interaction can also take place. Methods We synthesized the respective conjugates of aza‐18‐crown‐6, namely fluoro‐substituted N ‐nitrophenylaza‐18C6 conjugates. Their complexes with alkali and alkali earth metal cations were generated in the gas phase by electrospray ionization mass spectrometry (ESI‐MS). Both collision‐induced dissociation ‘in‐source’ and collision‐induced dissociation tandem mass spectrometry (ESI‐CID‐’in‐source’ and ESI‐CID‐MS/MS) were used to study the gas‐phase stabilities of the generated complexes. Results The gas‐phase decomposition of the studied complexes indicated that the complexes formed by the conjugates containing a nitro group at the ortho position are more stable than those formed by the conjugates with a nitro group at the para position. Conclusions This indicates that a metal cation complexed by crown ether ring is additionally coordinated by a nitro group in the scorpionate mode. To the best of our knowledge, our finding provide the first example of a complex in which a metal cation complexed by a crown ether ring is additionally coordinated by a nitro group.