TY - JOUR
T1 - A REKS Assessment of the Face-Diagonal Bond in 1,3-Didehydrocubane and a Comparison with Benzyne Biradicals
AU - De Visser, Sam P.
AU - Filatov, Michael
AU - Schreiner, Peter R.
AU - Shaik, Sason
PY - 2003/10/31
Y1 - 2003/10/31
N2 - The three isomeric cubane biradicals were studied using spin-restricted ensemble-referenced Kohn-Sham (REKS) density functional calculations at the B3LYP/6-31G(d) level of theory. The most stable biradical was found to be orthocubene with the meta-cubene and para-cubene biradicals 4.7 kcal mol -1 and 17.8 kcal mol-1 higher in energy, respectively. The singlet ground states are well separated from their lowest lying triplet states. These singlet-triplet energy differences mostly originate from through-space interactions for the ortho and meta isomers, whereas these interactions are rather weak for the para isomer. In contrast to para-benzyne, which was also considered for comparison with an unsaturated system, the singlet-triplet energy gap remains large in para-cubadiyl, mainly as a result of its much stronger through-bond interactions.
AB - The three isomeric cubane biradicals were studied using spin-restricted ensemble-referenced Kohn-Sham (REKS) density functional calculations at the B3LYP/6-31G(d) level of theory. The most stable biradical was found to be orthocubene with the meta-cubene and para-cubene biradicals 4.7 kcal mol -1 and 17.8 kcal mol-1 higher in energy, respectively. The singlet ground states are well separated from their lowest lying triplet states. These singlet-triplet energy differences mostly originate from through-space interactions for the ortho and meta isomers, whereas these interactions are rather weak for the para isomer. In contrast to para-benzyne, which was also considered for comparison with an unsaturated system, the singlet-triplet energy gap remains large in para-cubadiyl, mainly as a result of its much stronger through-bond interactions.
KW - Benzynes
KW - Density functional calculations
KW - Radicals
KW - Through-bond interactions
KW - Through-space interactions
UR - http://www.scopus.com/inward/record.url?scp=0242427559&partnerID=8YFLogxK
U2 - 10.1002/ejoc.200300201
DO - 10.1002/ejoc.200300201
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AN - SCOPUS:0242427559
SN - 1434-193X
SP - 4199
EP - 4204
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
IS - 21
ER -