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Electronic states of di‐t‐butylpolyacetylene radical cations
Author(s) -
Heilbronner Edgar,
Jones Taylor B.,
KlosterJensen Else,
Maier John P.
Publication year - 1978
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19780610611
Subject(s) - chemistry , ionization , ionization energy , x ray photoelectron spectroscopy , conjugated system , computational chemistry , alkyl , photoemission spectroscopy , radical ion , atomic physics , crystallography , ion , organic chemistry , nuclear magnetic resonance , physics , polymer
The π‐ionization energies of the di‐t‐butylpolyacetylenes with two, three, four and five conjugated triple bonds have been determined by He (Iα) photoelectron spectroscopy. The assignment of the bands to the Π ‐states of the corresponding radical cations follows from simple correlations in agreement with previous experience. The influence of the t ‐butyl groups on the ionization energies is rationalized in terms of traditional, qualitative arguments assuming an inductive and/or hyperconjugative mechanism. However, a more careful analysis shows that the ‘The ‐higher‐the‐ionization‐energy‐the‐higher‐the‐alkyl‐induced‐shift’ rule is not always true.