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Electrospray Behavior of Lacunary Keggin‐Type Polyoxotungstates [XW 11 O 39 ] p− (X = Si, P): Mass Spectrometric Evidence for a Concentration‐Dependent Incorporation of an MO n+ (M = W VI , Mo VI , V V ) Unit into the Polyoxometalate Vacancy
Author(s) -
Bonchio Marcella,
Bortolini Olga,
Conte Valeria,
Sartorel Andrea
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200390096
Subject(s) - chemistry , lacunary function , electrospray ionization , counterion , polyoxometalate , vanadium , alkali metal , ion , molybdenum , fragmentation (computing) , inorganic chemistry , mass spectrometry , electrospray , crystallography , analytical chemistry (journal) , chromatography , catalysis , organic chemistry , mathematics , computer science , pure mathematics , operating system
ESI‐MS analysis provides a straightforward tool for the solution characterization of highly charged mono‐lacunary Keggin‐type polyoxotungstates α‐[XW 11 O 39 ] p − (X = Si, P; p = 8, 7). Doubly and triply charged quasi‐molecular ion peaks were identified on the basis of both the theoretical simulation of the isotopic cluster distributions and the fragmentation modes observed with MS/MS technique. This approach allows the characterization of the inorganic polyanions transferred into the gas‐phase with associated alkali metal cations (Li + , Na + ). Indeed, the ESI‐MS spectrum was found to be dependent on the counterion nature and on the initial concentration of the polyoxotungstate. While lithium salts at millimolar concentration represent the best choice for the analytical protocol, upon dilution the inorganic structure rearranges to a saturated Keggin dodecametalate complex. This phenomenon is induced by the electrospray ionization process and was exploited to produce gas‐phase ions of monosubstituted species formed through incorporation of molybdenum and vanadium into the polyoxotungstate framework. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)