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Selenoketene (H 2 CCSe) +• and selenoketyl cumulene (HCCSe) + ions and their neutral counterparts: a tandem mass spectrometric and computational study
Author(s) -
Nagi Reddy P.,
Srikanth R.,
Bhanuprakash K.,
Srinivas R.
Publication year - 2005
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/jms.854
Subject(s) - chemistry , ion , cumulene , dissociation (chemistry) , electron ionization , isomerization , ab initio , analytical chemistry (journal) , density functional theory , tandem mass spectrometry , ionization , crystallography , mass spectrometry , computational chemistry , molecule , organic chemistry , catalysis , chromatography
Abstract Dissociative electron ionization (70eV) of selenophene (C 4 H 4 Se) generates m / z 106 ions of composition [H 2 , C 2 , 80 Se] +• and m / z 105 ions of [H, C 2 , 80 Se] + . From tandem mass spectrometric experiments, Density Functional Theory (DFT) and ab initio calculations, it is concluded that these ions have the structure of selenoketene H 2 CCSe +• (1a +• )and selenoketyl HCCSe + (2a + ) ions respectively. The calculations predict that selenoketene ion 1a +• is separated by high energy barriers from its isomers selenirene (H $\catcode`@=11 \def\overlsqmatrix#1{\null\vbox{\normalbaselines\m@th \ialign{\hfil$##$\hfil&&\quad\hfil$##$\hfil\crcr \mathstrut\crcr\noalign{\kern-\baselineskip} #1\crcr\mathstrut\crcr\noalign{\kern-\baselineskip}}}} \newdimen\rulwidth \def\downsqbrace#1{\setbox1=\hbox{#1} \rulwidth=\wd1\advance \rulwidth by -6pt \raise3pt\hbox{$\overlsqmatrix{\vrule height5pt\kern-0.5pt\raise5pt\hbox to \rulwidth{\hrulefill}\kern-0.5pt\vrule height5pt\cr\noalign{\vskip-3pt}\hbox{#1}\cr\noalign{\vskip-5pt}}$}} \catcode`@=12 \downsqbrace{{\rm CCHS}}$ e) +• 1b +• , ethyne selenol (HCCSeH) +• 1c +• , (CCHSeH) +• 1d +• and (CCSeH 2 ) +• 1e +• . The selenoketyl ion 2a + is separated by high barriers from its isomers (CCHSe) + 2b + , and (CCSeH) + 2c + . Neutralization‐reionization mass spectra (NRMS) of these structurally characterized ions confirmed that the corresponding neutral analogues, selenoketene H 2 CCSe 1a and selenoketyl radical HCCSe 2a • are stable in the rarefied gas phase. The relative, dissociation, and isomerization energies for selenoketene and selenoketyl ions and neutrals studied at B3LYP/6–31G(d,p) and G2/G2(MP2) levels are used to support and interpret the experimental results. Copyright © 2005 John Wiley & Sons, Ltd.