Db. Chesnut et Lj. Bartolotti, The pair density description of aromaticity in some substituted cyclopentadienyl systems: a comparison of AIM and ELF bonding descriptors, CHEM PHYS, 257(2-3), 2000, pp. 175-181
Calculations at the B3LYP/6-31 +G(d,p)//MP2(FC)/6-31+G(d,p) level of the at
oms-in-molecules interbasin pair numbers were carried out for a number of s
ubstituted cyclopentadienyl five-membered rings and compared to the electro
n localization function (ELF) bond basin populations. A smooth correlation
is found for the formally single C-C bond pair number with the correspondin
g homomolecular-homodesmotic resonance energy, as was previously been shown
for the ELF bond basin numbers. The two measures of bonding are essentiall
y equal for the non-polar C-C bond, but this is shown to be an exception ra
ther than a rule, the situation being more complex when bonds are polar and
/or lone pairs are nearby. (C) 2000 Elsevier Science B.V. All rights reserv
ed.