Segregated self-assembly and pillaring action of aliphatic dicarboxylic acids in the super structure of Cu–picolinate complexes

Three new supramolecular assemblies of co-crystallized metal complexes and aliphatic dicarboxylic acids, {[Cu(pic)2(H2O)2](H2mal)}n (1), {[Cu(pic)2(H2O)2](H2mal)2(H2O)2}n (2) and {[Cu(pic)2(MeOH)](H2succ)}n (3) {Hpic = 2-picolinic acid, H2mal = malonic acid and H2succ = succinic acid} have been synthesized and characterized by X-ray single-crystal structure determination. The crystal packings of the complexes reveal that supramolecular associations of the monomeric complex units lead to the formation of layers through hydrogen bonding. In all the complexes, the dicarboxylic acid units connect the 2-D layers to act as pillars. The interaction between water molecules and the dicarboxylic acid plays an important role in the overall supramolecular assembly.

Graphical abstractCo-crystals of [Cu(2-picolinate)2] and malonic or succinic acid reveal that supramolecular association of the monomeric complex units leads to the formation of layers through hydrogen bonding. The co-crystallized dicarboxylic acid connects these 2-D layers, acting as pillars to form the final 3-D supramolecular structure.Figure optionsDownload full-size imageDownload as PowerPoint slide