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The influence of ligand substituents and donor atom sets on the gas phase electron attachment reactions of bis‐chelates of nickel(II)
Author(s) -
Dakternieks D. R.,
Fraser I. W.,
Garnett J. L.,
Gregor I. K.,
Guilhaus M.
Publication year - 1980
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210151103
Subject(s) - substituent , chemistry , ligand (biochemistry) , nickel , ion , electron ionization , mass spectrum , atom (system on chip) , fast atom bombardment , ionization , crystallography , medicinal chemistry , organic chemistry , biochemistry , computer science , embedded system , receptor
Electron attachment reactions and negative ion mass spectra which were obtained under negative chemical ionization conditions have been examined for a series of 21 nickel(II) bis‐chelates of formula Ni[R 1 CXCHCYR 2 ] 2 . Three ligand donor atom sets (X, Y), respectively O 4 , O 2 S 2 , S 4 were investigated for each of the substituent combinations, viz.: R 1 =CH 3 , CF 3 or C 2 H 5 O, R 2 =CH 3 ; R 1 =C 6 H 5 , CH 3 or CF 3 , R 2 =C 6 H 5 ; and R 1 = R 2 = tert −C 4 H 9 . While the ligand substituent combinations exerted considerable influence over the various ion decomposition reactions, the relative molecular ion stabilities were largely dependent on the ligand donor atom sets and followed the sequence O 4 ⩾ O 2 S 2 >S 4 for most substituent combinations. Rationalizations are offered in terms of reductive electron capture reactions involving metal‐based orbitals, as well as the increasing stabilities of reaction products as sulphur is incorporated into the ligand donor atom sets. A comparison is also given of negative ion mass spectral data obtained under electron impact conditions as well as negative chemical ionization conditions when methane was used as an electron energy moderating gas.