Metal-Assembled, Resorcin[4]arene-Based Molecular Trimer for Efficient Removal of Toxic Dichromate Pollutants and Knoevenagel Condensation Reaction

Self-assembly of resorcin[4]­arene-based coordination cages involving more than two resorcin[4]­arenes poses significant challenges for the requirements of suitable functionalized resorcin[4]­arene ligands and metals. Here, we report an unusual example of a metal-coordinated, resorcin[4]­arene-based molecular trimer (1-NO3), composed of three resorcin[4]­arenes and three Cd­(II) cations. In particular, 1-NO3 features efficient and selective removal of environmentally toxic dichromate (Cr2O72–) anions. Moreover, the Knoevenagel condensation reaction was also explored by using 1-NO3 as an efficient heterogeneous catalyst.