Structural Transformation from Dimerization to Tetramerization of Serine-Decorated Rare-Earth-Incorporated Arsenotungstates Induced by the Usage of Rare-Earth Salts

Three types of serine-decorated rare- earth-containing arsenotungstate [H₂ N(CH₃ )₂ ]₆ NaH[RE₂ W₄ O₁₀ (H₂ O)₈ (Ser)₂ (B-α-AsW₉ O₃₃ )₂ ]⋅30 H₂ O (RE³⁺ =Eu³⁺ , Gd³⁺ , Tb³⁺ , Dy³⁺ , Ho³⁺ , Er³⁺ , Tm³⁺ , Yb³⁺ , and Y³⁺ ; 1), [H₂ N(CH₃ )₂ ]₆ Na_6-x RE_x H_{4-2 x} [RE₄ W₈ O₁₉ (H₂ O)_10+y (OH)₂ (Ser)₂ (B-α-AsW₉ O₃₃ )₄ ]⋅n H₂ O (RE³⁺ =Tb³⁺ , x=1, y=2, n=36; RE³⁺ =Dy³⁺ , Ho³⁺ , Er³⁺ , Yb³⁺ , Y³⁺ , x=0, y=0, n=38; RE³⁺ = Tm³⁺ , x=1, y=0, n=38; Ser=serine; 2), and [H₂ N(CH₃ )₂ ]_{6-2 x} Na_{2+3 x} RE_x H_{10-6 x+y} [RE₄ W₈ O₁₉ (H₂ O)₈ (OH)₂ (Ser)₄ (B-α-AsW₉ O₃₃ )₄ ]⋅Cl_y ⋅n H₂ O (RE³⁺ =Ce³⁺ , Pr³⁺ , x=1, y=0, n=65; RE³⁺ =Nd³⁺ , Sm³⁺ , x=0, y=0, n=65; RE³⁺ =Eu³⁺ , Gd³⁺ , x=1, y=2, n=45; 3) were synthesized with the participation of the organic solubilizers dimethylamine hydrochloride and l-serine and were structurally characterized. The use of different amounts of rare-earth salts results in the structural transformation from dimerization to tetramerization of types 1-3. Type 1 is a dimeric sandwich-type assembly of a dual-Ser-participating [RE₂ W₄ O₁₀ (H₂ O)₈ (Ser)₂ ]¹⁰⁺ entity sandwiched by two [B-α-AsW₉ O₃₃ ]^9- moieties, whereas types 2 and 3 have a tetrameric square structure formed by four [B-α-AsW₉ O₃₃ ]^9- moieties that anchor a dual/tetra- Ser-participating [RE₄ W₈ O₁₉ (H₂ O)_10+y (OH)₂ (Ser)₂ ]²⁰⁺ or [RE₄ W₈ O₁₉ (H₂ O)₈ (OH)₂ (Ser)₄ ]²⁰⁺ core. The solid-state luminescence properties and lifetime-decay behaviors of these compounds were investigated. The chromaticity coordinates, dominant wavelengths, color purities, and correlated color temperatures were also calculated.