Directed Self-Assembly of C4-Symmetric, Oxidovanadate-Centered, Vanadyl(V) Quadruplexes for Ba2+- and Hg2+-Specific Recognition, Transport, and Recovery.

Directed assembly of loosely, Na+-bound, oxidovanadate-centered quartets of C4-symmetry from tailor-made chiral N-salicylidene-vanadyl(V) complexes, for the first time, allows for highly efficient Ba2+- or Hg2+-specific detection (by 51V NMR and VCD), transport (forming a unique helical capsule or a capped square planar complex, respectively), and green recovery from an aqueous phase containing 4 different alkaline earth ions or from at least 10 different metal ions of similar size and charge capacity into the CHCl3 layer without interference from oxa- or oxophilic ions like Mg2+, Ca2+, Cu2+, Cd2+, and Pb2+.