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Gas‐phase structure, bonding, and fragmentation chemistry of the An (IV)–TMPDCAM complexes studied using mass spectrometry and theoretical calculation (An = Th and U)
Author(s) -
Xiong Zhixin,
Hu Jingwen,
Chen Xiuting
Publication year - 2021
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.9168
Subject(s) - chemistry , actinide , pyridine , thorium , lanthanide , dissociation (chemistry) , electrospray ionization , mass spectrometry , acetonitrile , collision induced dissociation , density functional theory , fragmentation (computing) , mass spectrum , crystallography , ion , computational chemistry , analytical chemistry (journal) , inorganic chemistry , tandem mass spectrometry , uranium , medicinal chemistry , organic chemistry , materials science , chromatography , computer science , metallurgy , operating system
Rationale Pyridine‐2,6‐dicarboxamides (PDCAMs) exhibit a certain extraction ability for tetravalent actinide ions, but quite limited information regarding the structures and reactivities of the corresponding An 4+ ‐PDCAMs complexes is available. Neutral diamides can form multiply charged complexes with lanthanide and actinide cations, which are well suited for gas‐phase investigations using electrospray ionization (ESI) mass spectrometry in conjunction with theoretical calculation. Methods Binary Th (TMPDCAM) 3 4+ /U (TMPDCAM) 3 4+ (TMPDCAM = N , N , N ′, N ′‐tetramethylpyridine‐2,6‐dicarboxamide) complexes were generated in the gas phase via ES) of Th (ClO 4 ) 4 /U (ClO 4 ) 4 and TMPDCAM mixtures in acetonitrile; collision‐induced dissociation (CID) was employed to reveal their fragmentation behaviors; the structure and bonding were investigated by density functional theory (DFT) calculation. Results An (TMPDCAM) 3 4+ (An = Th and U) tetracations dominated the ESI mass spectra of An (ClO 4 ) 4 and TMPDCAM mixtures in acetonitrile. DFT calculations indicate that the two An (TMPDCAM) 3 4+ complexes have C 3 geometry, and the bonding analyses demonstrate that the thorium or uranium center interacts with both O carbonyl and N pyridine , but the latter is weaker. CID of Th (TMPDCAM) 3 4+ generated a series of multiply charged thorium‐containing products via bond cleavages of the TMPDCAM ligand, whereas U (TMPDCAM) 3 4+ yielded only oxygen extraction product UO (TMPDCAM) 2+ and hydrolysis product UO (OH) + . Conclusion An 4+ (An = Th and U) can form stable tetrapositive complexes in the gas phase on coordination of three neutral TMPDCAM ligands. The structure and bonding analyses indicate that the two An (TMPDCAM) 3 4+ complexes possess twisted tricapped trigonal prismatic geometry and the An 4+ centers are coordinated by six O carbonyl and three N pyridine atoms while the interactions between An 4+ and O carbonyl are stronger. The fragmentation chemistry of Th (TMPDCAM) 3 4+ and U (TMPDCAM) 3 4+ is quite different from each other, which reveals that the gas‐phase chemistry of quadruply charged actinide–diamide complexes is affected by the metal centers with distinct properties.