Engineering the Solid State with 2-Benzimidazolones

Six derivatives of 2-benzimidazolone, disubstituted in the 4 and 5
positions, have been synthesized, and
their structures have been determined in the solid state. Four of
these compounds crystallize as molecular tapes.
Compounds 1-(CH3)2,
1-Cl2, and 1-Br2 form
tapes that pack with their long axes parallel; compounds
1-H2 and
2-H2 form tapes that pack with their long axes
at an angle to one another. Compounds 1-F2
and 1-I2 crystallize with
a three-dimensional network of hydrogen bonds. The packing
arrangement of molecular tapes is rationalized on the
basis of closest packing and electrostatic interactions between
aromatic rings. The occurrence of the network motif
rather than the tape motif for 1-F2 and
1-I2 is rationalized on the basis of secondary
interactions involving the
halogen atoms.