Structural modulation of polythreading and interpenetrating coordination networks with an elongated dipyridyl building block and various anionic co-ligands

This work presents a series of coordination polymers with a dipyridyl-type building block bis[3,5-dimethyl-4-(4'-pyridyl)pyrazol-1-yl]methane (pypz) and different anionic co-ligands. The elongated and flexible backbone of the pypz ligand facilitates the formation of diverse entangled coordination networks, which are well regulated by the auxiliary anionic components. Generally, the anions of nitrate, chloride, and pseudohalide ( such as dicyanamide, thiocyanate, and azide) display a monodentate binding mode in this system and serve as terminal pendants of the metal-pypz coordination layers. As a result, 2D -> 3D polythreading architectures are mostly observed, except in the case of small chloride anion that leads to twofold parallel interpenetration of the layers. On the other hand, the aromatic dicarboxylates such as terephthalate and biphenyl- 4,4'-dicarboxylate behave as rod-like linkers for the construction of diversiform 2D or 3D interpenetrated coordination networks with the aid of pypz. Besides, these crystalline materials may also be significantly affected by other assembled elements such as metal ion, solvent, and metal-to-ligand ratio.