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Direct synthesis and electron‐ionization positive‐ion mass spectrum of tetrakis(acetylacetonato)cerium(IV), Ce(C 5 H 7 O 2 ) 4
Author(s) -
Chaudhuri Mihir K.,
Islam Nashreen S.,
Khathing Darlando T.,
Shylla Vicky G.,
Mathur D.
Publication year - 1989
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.1290030911
Subject(s) - chemistry , cerium , ion , acetylacetone , mass spectrum , electron ionization , electron transfer , ionization , analytical chemistry (journal) , fragmentation (computing) , inorganic chemistry , crystallography , organic chemistry , chromatography , computer science , operating system
Crystalline Ce(C 5 H 7 O 2 ) 4 has been synthesized directly from the reaction of hydrated cerium(IV) oxide with acetylacetone, (C 5 H 8 O 2 ), and its electron‐ionization (EI) mass spectrom is reported. The compound exists as a monomer (mass 536) in the gaseous state. The mass spectrum, like those of M(C 5 H 7 O 2 ) 4 (M = Zr or Th) and CeL 4 (L = fluorinated β‐diketonate), shows the dominant ion signal to be due to the [Ce(C 5 H 7 O 2 ) 3 ] + ion that arises from the loss of one C 5 H 7 O 2 from the molecular ion. An internal electron‐transfer affords [Ce(C 5 H 7 O 2 ) 3 ] + ˙. Fragmentation of [Ce(C 5 H 7 O 2 ) 3 ] + ˙ to [Ce(C 5 H 7 O 2 ) 2 ] + is similar to that observed for the tris‐chelates of trivalent transition metals and La(C 5 H 7 O 2 ) 3 . The ion [Ce(C 5 H 7 O 2 ) 2 ] + ultimately breaks down to [CeO] + through the sequential loss of three even‐electron neutral species, CH 3 COCHCCH 2 , H 2 O and CH 3 COCHCCH 2 without invoking any further reduction of the Ce centre. Mechanisms are given for the loss of the three even‐electron species from the bis(acetylacetonato)cerium(III) ion fragment. Theoretical simulations of patterns of the fragment ions [Ce(C 5 H 7 O 2 ) 3 ] + ˙, [Ce(C 5 H 7 O 2 ) 2 ] + ˙, and [Ce(C 5 H 7 O 2 )OH] + have been made and compared with those of the corresponding experimental results in support of the suggested mode of fragmentation.