Oligomeric and polymeric organizations of potassium salts with compartmental Schiff-base complexes as ligands

Abstract

The complexation of K+ ions by mono-metallated bicompartmental Schiff-base complexes in double-decker-type arrangement was found to yield various supramolecular organizations as a function of the associated anions. A series of four [{LMK}n{LM}]n+ aggregates with n = 1, 2, 3, and ∞ are reported (M = Ni2+ or Cu2+; L stands for the Schiff-base). Assembling KNCS with the metallo-ligand led to 1-D [L3CCuK(NCS)]n whereas KOH yielded the simplest possible case, [(L2CNi)2KOH]·H2O. Oligomeric organizations containing two or three alkali ions were achieved in the presence of the [Mo(NCS)6]3− anion. Such stacks have not been found with Na2+ due to a different local arrangement with the metallo-ligand. The crystal packing for [(L2CNi)2KOH]·H2O yields an open-framework structure with a void volume of 20%.