102128-66-5Relevant academic research and scientific papers
Squaraine chemistry. On the anomalous mass spectra of bis(4-dimethylaminophenyl)squaraine and its derivatives
Law, Kock-Yee,Bailey, F. Court,Bluett, Lynn J.
, p. 1607 - 1619 (2007/10/02)
The electron inpact (EI) mass spectra of bis(4-dimethylaminophenyl)squaraine 1 and its derivatives 2-14 have been studied.Ions of mass number higher than the molecular ion, wich are shown to be precursors of fragment ions of lower mass numbers, are observed.From the structure-property relationship, these ions are assigned to M + CHR and M + H2 , were CH2R is the alkyl group in the N,N-dialkylanilino moiety of squaraine.Evidence is provided that the formation of M + CHR and M + H2 is the result of alkyl transfer and H transfer reactions within a squaraine aggregate rather than intermolecular vapor phase reeactions in the massspectrometer.This molecular aggregate is later shown to be a trimer by analysis of metastable ion data and chemical ionization mass spectrometry.The fragmentation sequence of this trimeric species is elucidated with the assistance of metastable ions.Results show that the trimer may break down to monomeric and dimeric species upon electron impact; alternatively,the four-membered ring of the central squaraine in the trimer may cleave to generate two species of approximately equal mass number.These two species usually dominate the mass spectrum and further fragment into M + CHR and M + H2.Detailed fragmentation schemes for M + CHR and M + H2 are proposed and discussed.
