Investigating the Formation of Different (NH₄)₂[<em>M</em>(H₂O)₅(NH₃CH₂CH₂COO)]₂[V₁₀O₂₈]·<em>n</em>H₂O (<em>M</em> = Co^II, Ni^II, Zn^II, <em>n</em> = 4; <em>M</em> = Cd^II, Mn^II, <em>n</em> = 2) Crystallohydrates

Abstract

Three hybrid compounds based on decavanadates, i.e., (NH4)2[Co(H2O)5(β-HAla)]2[V10O28]·4H2O (1), (NH4)2[Ni(H2O)5(β-HAla)]2[V10O28]·4H2O (2), and (NH4)2[Cd(H2O)5(β-HAla)]2[V10O28]·2H2O (3), (where β-Hala = zwitterionic form of β-alanine) were prepared by reactions in mildly acidic conditions (pH ~ 4) at room temperature. These compounds crystallise in two structure types, both crystallising in monoclinic P21/n space group but with dissimilar cell packing, i.e., as tetrahydrates (1 and 2) and as a dihydrate (3). An influence of crystal radii and spin state of the central atom in [M(H2O)5(β-HAla)]2+ complex cations on the crystal packing leading to the formation of different crystallohydrate forms was investigated together with previously prepared (NH4)2[Zn(H2O)5(β-HAla)]2[V10O28]·4H2O (4) and (NH4)2[Mn(H2O)5(β-HAla)]2[V10O28]·2H2O (5) and spin states of [M(H2O)5(β-HAla)]2+ (M = Co2+, Ni2+, and Mn2+) cations in solution were confirmed by 1H-NMR paramagnetic effects. FT-IR and FT-Raman spectra for 1–5 are in agreement with the X-ray structure analysis results.

Keywords

• hybrid decavanadates
• β-alanine
• crystallohydrates
• crystal structure
• vibrational spectroscopy
• paramagnetic NMR