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Ion–molecule reactions in a quadrupole ion trap as a probe of the gas‐phase structure of metal complexes
Author(s) -
Vachet Richard W.,
Hartman Judith Ann R.,
Callahan John H.
Publication year - 1998
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199812)33:12<1209::aid-jms738>3.0.co;2-w
Subject(s) - chemistry , ethylamine , reagent , inorganic chemistry , molecule , pyridine , quadrupole ion trap , reactivity (psychology) , denticity , metal , ion trap , metal ions in aqueous solution , ion , organic chemistry , medicine , alternative medicine , pathology
A method is described in which the coordination number in metalcomplexes can be determined using ion–molecule reactions in aquadrupole ion trap mass spectrometer. Complexes of first‐rowtransition metals in the +2 oxidation state, including manganesethrough zinc, are electrosprayed, isolated in the ion trap and allowedto react with gases. The coordination number is ascertained byobserving the reagent ligands that successfully react with thecomplex. It was generally observed that six‐coordinatecomplexes are unreactive, five‐coordinate complexes react withpyridine and ethylamine, four‐coordinate complexes react withpyridine, ethylamine and ammonia and threecoordinate complexes reactwith all the reagent ligands studied, including water and methanol.The order of reactivity for a given complex reacting with the variousreagent ligands is found to follow the order of theelectron‐donating ability of the reagent ligands. In addition,the effect of the metal center on the reactivity of the complexes inthe gas phase is analogous to solution‐phase trends; electronicstructure strongly influences the gas‐phase reactions. Theseresults were then used to predict the complexation behavior of novelpodand ligands for which condensed phase information is not available.The results indicate that ion–molecule chemistry in the gasphase may be useful in predicting the interactions between novelmultidentate ligands and metals in solution. © 1998 John Wiley& Sons, Ltd.