A series of seven
N
-phenylamides [R–C(O)NHPh,
in which R: CH
3
, C(CH
3
)
3
, Ph, CF
3
, CCl
3
, CBr
3
, and H] were used as models
in this study. Molecular packing and intermolecular interactions were
evaluated by theoretical calculations, solution NMR, and quantum theory
of atoms in molecules analyses. Crystallization mechanisms were proposed
based on the energetic and topological parameters using the supramolecular
cluster as demarcation. Concentration-dependent
1
H NMR
experiments corroborated the proposed interactions between molecules.
For all compounds (except for R: H, which initially formed tetramers),
layers (two-dimensional) or chains (one-dimensional) were formed in
the first stage of the proposed crystallization mechanisms. The presence
of strong intermolecular NH···O=C interactions
promoted the first stages. The study in solution provided different
values of association constant (
K
ass
)
governed by the hydrogen bond NH···O=C, showing
that the stronger interactions are directly influenced by the substituent
steric hindrance. A correlation between
K
ass(NH···O=C)
from the solution and the NH···O=C interaction
energy in the crystal showed a good trend.