A New Series of Zn^II Coordination Polymer Based Metallogels Derived from Bis-pyridyl-bis-amide Ligands: A Crystal Engineering Approach

Abstract

On the basis of a recently demonstrated crystal engineering strategy, two hydrogen bond equipped bidentate ligands, namely, N,N′-bis-(3-pyridyl)isophthalamide L1 and N,N′-bis-(3-pyridyl)terephthalamide L2, have been exploited to generate a new series of ZnII-coordination polymer based metallogels. As many as 12 metallogels have been prepared by the reaction of these ligands with various ZnII halides under various conditions. The gels were characterized by rheology, scanning electron microscopy (SEM), and powder X-ray diffraction (PXRD). A structure−property correlation study based on the PXRD of the xerogels and single crystal X-ray diffraction (SXRD) data of some of the isolated single crystals of the reaction products clearly establishes the structures of the gel fibers in the xerogels and supports the crystal engineering based design strategy based on which metallogels are prepared.