Which NICS aromaticity index for planar pi rings is best?
Five increasingly sophisticated aromaticity indexes, based on nucleus-independent chemical shifts (NICS), were evaluated against a uniform set of aromatic stabilization energies (ASE) for 75 mono- and polyheterocyclic five-membered rings. While acceptable statistical correlations were given by all of the NICS methods, the most fundamentally grounded index, NICS(0)pizz (based on the pi contribution to the out-of-plane zz tensor component), performed best statistically (cc=0.980) and in practice. The easily computable NICS(1)zz index is a useful alternative (cc=0.968).
Department of Chemistry, Islamic Azad University-Rasht Branch, P.O. Box 41335-3516, Rasht, Iran. h_fallah@iaurasht.ac.ir
Hossein
H
Fallah-Bagher-Shaidaei
Chaitanya S
CS
Wannere
Clémence
C
Corminboeuf
Ralph
R
Puchta
Paul v R
Pv
Schleyer