Synthesis and 3D Network Architecture of 1- and 16-Hydrated Salts of 4-Dimethylaminopyridinium Decavanadate, (DMAPH)6[V10O28]·nH2O

Two hybrid materials based on decavanadates (DMAPH)6[V10O28]·H2O, (1) and (DMAPH)6[V10O28]·16H2O, (2) (where DMAPH = 4-dimethylaminopyridinium) were obtained by reactions under mild conditions at T = 294 and 283 K, respectively. These compounds are pseudopolymorphs, which crystallize in monoclinic P 2 1 / n and triclinic P 1 ¯ space groups. The structural analysis revealed that in both compounds, six cations DMAPH+ interact with decavanadate anion through N-H∙∙∙Odec hydrogen bonds; in 2, the hydrogen-bonding association of sixteen lattice water molecules leads to the formation of an unusual network stabilized by decavanadate clusters; this hydrogen-bond connectivity is described using graph set notation. Compound 2 differs basically in the water content which in turn increases the π∙∙∙π interactions coming from pyridinium rings. Elemental and thermal analysis (TGA/DSC) as well as FT-IR, FT-Raman, for 1 and 2 are consistent with both structures and are also presented.