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Physical and Chemical Interaction of Homoconjugated Dienes with Tetracyanoethylene
Author(s) -
Haselbach Edwin,
Rossi Michel
Publication year - 1976
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.19760590803
Subject(s) - tetracyanoethylene , chemistry , hydrocarbon , dehydrogenation , decane , medicinal chemistry , bicyclic molecule , organic chemistry , catalysis
EDA‐complexes of bicyclo[2,2,n]alkadienes (n = 1, 2, 3, 4) ( 1 (n)‐series), 1,4‐cyclohexadiene ( 2 ) and various other cyclic monoenes, dienes and trienes as donors and tetracyanoethylene (TCNE) as acceptor were investigated. Spectroscopic and thermodynamic constants of the complexes were determined and correlated with the ionisation potentials (I D ) of the hydrocarbon donors obtained from PE. spectroscopy. The nature of the dominant energy contributions to the ground state and the two lowest CT‐states of these weak complexes is discussed and structural conclusions are drawn. The role of the complexes in the addition reaction of the hydrocarbon components and TCNE is discussed. The homo Diels‐Alder addition product of 1 (2) and TCNE, 9,9,10,10‐tetracyanoquadricyclo[2,2,2,0 2,6 ,2 3,5 ]decane, and the ‘ene’‐addition product of 2 and TCNE, 5‐[1′,1′,2′,2′‐tetracyanoethyl]‐1,3‐cyclohexadiene were prepared and characterized. Preliminary results for the mechanistic scheme governing the dehydrogenation of 2 by TCNE are reported.