Structural properties of supramolecular metallogel derived from vanadium and hydrazone ligand: Metallogelation triggered by hydrogen bonding, pi–pi interactions and other non-covalent interactions

An approach to develop an easy strategy for the synthesis and characterization a new vanadium-based metallogels was developed. In this study, vanadium was selected for the current investigation because only few vanadium-based gels have been reported in the literature. The gelation experiments were carried out successfully using vanadium acetylacetonate and hydrazone ligand in different solvents. The metallogel shows excellent gelation ability with 1.7 wt% minimum gelator concentrations and the gel–sol dissociation temperature, T_gel, is 55 °C (water/methanol). The viscous and elastic characteristics of gel materials were also studied and the strength of the metallogel was characterized by storage (G′) and loss moduli (G′′). It was found that the storage modulus (G′) value was significantly larger compared to the loss modulus (G′′) value, which confirmed the gel nature of the material. The structural properties of the metallogel were studied by using single crystal x-ray crystallography. The crystal structure data analysis of the metallogel shows the presence of various interactions such as hydrogen bonding, pi–pi interactions, pnicogen bonding and other weak non-covalent interactions that stabilised the structure of the metallogels. The presence of various intra- and intermolecular interactions significantly influences the behaviour and properties of the metallogels. These intermolecular interactions play an important role in gel formation and affect properties like swelling behaviour, viscosity and elasticity.