Ag(I)-triazolylcarboxylates: The role of hydrocarbon tails in the formation of “sitting-on-layer” supramolecular bowls

Abstract

Several α-amino acids, (l,d)-alanine and (l,d)-phenylalanine were utilized, as precursors for synthesis of 1,2,4-triazolyl carboxylic acids (l,d)-trala-H and (l,d)-trphe-H, which were explored as angular bifunctional building blocks for engineering Ag(I)-coordination polymers. Two complexes, [Ag(μ4-trala)]·H2O (1) and [Ag(μ4-trphe)]·H2O (2), were prepared under mild hydrothermal conditions and characterized. The organic ligands coordinate silver cations in a deprotonated form via a N2O2 donor set, where the tr group behaves in a [N–N] mode while the carboxylate function serves as a μ2-η2:η0 bridge. Complexes 1 and 2 possess a layered structure consisting of [Ag([N–N]-tr)(COO)]n chains which are interlinked through ligand spacers. Being oriented toward the neighboring layers, the hydrocarbon side “tails” display a peculiar role in the supramolecular organization of “sitting-on-layer” three-dimensional baskets. Each container is pleasantly suitable for binding a water molecule via an H-bonding acceptor portal of carboxylate fragments.