TY - JOUR
T1 - Mapping the modification of ring currents induced by cyclopentafusion on a naphthalene core
AU - Fowler, P. W.
AU - Steiner, E.
AU - Acocella, A.
AU - Jenneskens, L. W.
AU - Havenith, R. W.A.
PY - 2001
Y1 - 2001
N2 - An analysis of the σ-, π- and total current density maps, calculated using a distributed-origin coupled Hartree-Fock method, of the non-alternant cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAH) acenaphthylene (1), pyracylene (2), fluoranthene (3) and cyclopenta[cd]fluoranthene (4) shows that, whereas the presence of a single pentagon in 1 and 3 has only minor effects on the core naphthalene unit, the strong cooperative effect of the two pentagons connected by a formal double bond in 2 and 4 results in intense paratropic currents in the pentagons, and markedly reduced aromaticity according to conventional criteria. The accuracy of the all-electron maps is supported by calculation of 1H and 13C NMR chemical shifts in agreement with experiment and their interpretation is consistent with nucleus-independent chemical shifts (NICS values). It is shown that the pattern of paratropic contributions can be explained qualitatively within Hückel-London π-electron theory.
AB - An analysis of the σ-, π- and total current density maps, calculated using a distributed-origin coupled Hartree-Fock method, of the non-alternant cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAH) acenaphthylene (1), pyracylene (2), fluoranthene (3) and cyclopenta[cd]fluoranthene (4) shows that, whereas the presence of a single pentagon in 1 and 3 has only minor effects on the core naphthalene unit, the strong cooperative effect of the two pentagons connected by a formal double bond in 2 and 4 results in intense paratropic currents in the pentagons, and markedly reduced aromaticity according to conventional criteria. The accuracy of the all-electron maps is supported by calculation of 1H and 13C NMR chemical shifts in agreement with experiment and their interpretation is consistent with nucleus-independent chemical shifts (NICS values). It is shown that the pattern of paratropic contributions can be explained qualitatively within Hückel-London π-electron theory.
UR - http://www.scopus.com/inward/record.url?scp=0034743062&partnerID=8YFLogxK
U2 - 10.1039/b102413m
DO - 10.1039/b102413m
M3 - Article
AN - SCOPUS:0034743062
SN - 1470-1820
VL - 2
SP - 1058
EP - 1065
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 7
ER -