  In a recent paper [J. Organomet. Chem. (2013) doi: 10.1016 /j.jorganchem.
2013.03.047] analyzing the bonding mode of Trimethylenemethane (TMM) with some
metal carbonyls, Mousavi and Frenking have declared the absence of bond paths,
the so-called missed bond paths, between metal atoms and terminal carbon atoms
in several complexes. In this communication, it is first demonstrated that the
presupposition of the equivalence of a bond path and a chemical bond within the
context of the quantum theory of atoms in molecules (QTAIM) is superficial and
basically flawed which is not only against with the recent strict declaration
on the contrary [R.F.W. Bader, J. Phys. Chem. A 113 (2009) 10396], but also in
odd with the foundations of the QTAIM. Then, it is demonstrated that the
so-called missed bond paths indeed appear in molecular graphs of some
non-equilibrium geometries that are energetically quite accessible at room
temperatures. To emphasize on the importance of this observation the term
passionate neighbors is coined referring to the atomic basins that do not share
an inter-atomic surface at the equilibrium geometry but are neighbors, share an
inter-atomic surface, at non-equilibrium geometries accessible by nuclear
vibrations. Using the delocalization index as well as other evidence from
previous literature it is demonstrated that the QTAIM analysis is indeed
compatible with the presence of chemical bonds between iron metal and terminal
carbons in (CO)3Fe-TMM complex. Finally, some general discussions are done to
unravel the delicate relationship between the QTAIM proposed concepts, e.g.
bond paths and molecular graphs, and some orthodox concepts of chemistry, e.g.
chemical bonds and chemical structures, emphasizing that there is no one-to-one
relationship between these two categorizes.
