Hydrogen Bonded Dimers of Triurea Derivatives of Triphenylmethanes

Tri-(2-alkoxy-5-ureido-phenyl)methanes represent a novel self-complementary motif forming hydrogen bonded homo- and heterodimers in nonpolar, aprotic solvents as evidenced by 1H NMR and ESI-mass spectra and by the formation of heterodimers. MD simulations suggest the formation of hydrogen bonds of different strength in agreement with NMR data. The dimerization does not interfere with that of tetraurea calix[4]arenes. A combination of both motifs may be used therefore to build up larger structures via self-assembly processes.