The ability of carbon radicals to act as hydrogen bond accepters has b
een evaluated using ab initio theoretical methods. A hybrid Hartree-Fo
ck Density Functional Theory based method (B3LYP), Moller-Plesset at t
he second perturbation order (MP2), and Quadratic CI methods that incl
ude single and double excitation (QCISD), have been used. The complexe
s formed by four radicals CH3(d), C2H4(t). (CH3)(2)C(t) and (CH3)(3)C(
d)] with four standard hydrogen bond donors [FH, H2O, HCN and H3N] hav
e been studied and their geometry, interaction energy, and electronic
properties, within the Atoms in Molecules (AIM) methodology framework
have been analyzed. The energy and geometry results show that the stud
ied radicals are poor hydrogen bond (HB) accepters and the strength of
the HBs qualitatively correlates with the molecular electrostatic pot
ential (MEP) minimum of the isolated radicals. The atomic partition of
different properties using the AIM methodology indicates that HBs com
plexes involving radicals behave differently to other HBs formed betwe
en neutral molecules.