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 [H₂N(CH₃)₂]₆NaH[RE₂W₄O₁₀(H₂O)₈(Ser)₂(B-α-AsW₉O₃₃)₂]⋅30 H₂O (RE³⁺=Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, and Y³⁺; 1), [H₂N(CH₃)₂]₆Na_6−xRE_xH_{4−2 x}[RE₄W₈O₁₉(H₂O)_10+y(OH)₂(Ser)₂(B-α-AsW₉O₃₃)₄]⋅n H₂O (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 [H₂N(CH₃)₂]_{6−2 x}Na_{2+3 x}RE_xH_{10−6 x+y}[RE₄W₈O₁₉(H₂O)₈(OH)₂(Ser)₄(B-α-AsW₉O₃₃)₄]⋅Cl_y⋅n H₂O (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 [RE₂W₄O₁₀(H₂O)₈(Ser)₂]¹⁰⁺entity sandwiched by two [B-α-AsW₉O₃₃]⁹⁻moieties, whereas types 2 and 3 have a tetrameric square structure formed by four [B-α-AsW₉O₃₃]⁹⁻moieties that anchor a dual/tetra- Ser-participating [RE₄W₈O₁₉(H₂O)_10+y(OH)₂(Ser)₂]²⁰⁺or [RE₄W₈O₁₉(H₂O)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.