Metal-ion chemistry of tetra(meso-4-phenoxy-2-picolyl)-calix[4]pyrrole: An extendable super-cavitand tetrapodal ligand

That calix[4]pyrrole cavitands appended with ligand donor groups should have a rich coordination chemistry is demonstrated by the facile preparation and preliminary investigations of a calix[4]pyrrole adorned with four meso-4-phenoxymethyl-2-pyridyl arms (1); an ESI-FTICR-MS study reveals that 1 selectively binds Cs+ out of the alkali metal ions, whereas the reaction of 1 and [PdCl2(PhCN)2] afforded a novel dimer, [(1)(PdCl2)2], that X-ray crystallography reveals to be chalice-shaped with the PdII centres at the chalice lips and a DMF guest tightly bound within the super-extended cavity and a second DMF guest within the obverse concave annulus formed by the four pyrroles.

Graphical abstractThe preparation of 1 demonstrates that ligand donor appended calix[4]pyrroles are simply made, and preliminary results illustrate the rich potential of such ligands: ESI-FTICR-MS studies reveal that 1 selectively binds to cesium ion out of the alkali metal cations and the synthesis and crystal structure of the chalice-shaped Pd(II) dimer [Pd2(1)Cl4] · 5.5dmf · 1.5H2O are described.Figure optionsDownload full-size imageDownload as PowerPoint slide