Green Synthesis, Crystal Structure and Bioactivity of C-(psubstituted phenyl)calix[4]resorcinarenes-DMSO Inclusion Complexes

Green synthesis of calix[4]resorcinarene hosts with p-substituted phenyl group at their methine carbons was achieved. Fluorine, chlorine and bromine atoms, as well as methoxy group, were selected as substituents at the para position of the benzaldehyde which was condensed with resorcinol in presence of solid p-toluenesulfonic acid. The solid state structures of the newly prepared C-(p-fluorophenyl)calix[4]resorcinarene-DMSO and C-(p-chlorophenyl)-calix[4]resorcinarene-DMSO inclusion complexes were determined by single-crystal X-ray diffraction and found to form different structural conformations; chair (C2h) and boat (C2v), respectively. In addition, both crystal structures adopted several intermolecular noncovalent supramolecular interactions which were carefully investigated and presented in terms of crystal engineering and supramolecular chemistry. The synthesized C-(p-substitutedphenyl)calix[4]-resorcinarene hosts inhibited the growth of Gram-positive bacteria with the C-(p-bromophenyl)-calix[4]resorcinarene derivative being the most potent agent (MIC=15.6-125 μg/ml).