Propanediurea Dimer Clips


                                  Tomáš Lízal,^ Vladimír Šindelář
                                                 ^


Propanediurea is a heterocyclic compound analogous to glycoluril. It’s a suitable building block
for supramolecular objects such as molecular clips^1 and macrocycles.^2

Here we report synthesis of the new molecular clips based on a dimer of o‑xylylene walled
propanediurea (Fig. 1: 1, 2). Dimers were characterized by means of NMR, HRMS and X‑ray
crystallography. Supramolecular interactions between clips and halide anions were studied by NMR
titration experiments.

In a non-polar solution the dimers act as a host for halide anions. Weak binding of guest molecules
surprisingly proceeds on a concave side of dimer instead of the cavity formed by o-xylylene groups.
The complexes features C-H∙∙∙X^- bond between methine protons and anions. Geometry of complex were
further studied by DFT calculations.




Fig. 1













1)         Jansen, R. J.; Rowan, A. E.; Nolte R. J. Chem. Commun. 1998, 121.

2)         Ustrnul, L.; Kulhánek P.; Lízal, T.; Šindelář, V. Org. Lett. 2015, 17, 1022.