Effect of pH and Reaction Time on the Structures of Early Lanthanide(III) Borate Perchlorates

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• 作者：Matthew J. Polinski ; Shuao Wang ; Evgeny V. Alekseev ; Justin N. Cross ; Wulf Depmeier ; Thomas E. Albrecht-Schmitt
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：November 5, 2012
• 年：2012
• 卷：51
• 期：21
• 页码：11541-11548
• 全文大小：479K
• 年卷期：v.51,no.21(November 5, 2012)
• ISSN：1520-510X

文摘

Reactions of LnCl₃路6H₂O (Ln = La鈥揘d, Sm, Eu), concentrated (11 M) perchloric acid, and molten boric acid result in the formation of four different compounds. These compounds are Ln[B₈O₁₀(OH)₆(H₂O)(ClO₄)]路0.5H₂O (Ln = La鈥揘d, Sm), Pr[B₈O₁₁(OH)₄(H₂O)(ClO₄)], Ln[B₇O₁₁(OH)(H₂O)₂(ClO₄)] (Ln = Pr, Nd, Sm, and Eu), and Ce[B₈O₁₁(OH)₄(H₂O)(ClO₄)]. All Ln(III) cations are ten-coordinate with a capped triangular cupola geometry and contain an inner-sphere, monodentate perchlorate moiety. This geometry is obtained because of the coordination of the oxygen donors within the polyborate sheet which create triangular holes and provide residence for the lanthanide metal centers. Aside from Ln[B₈O₁₀(OH)₆(H₂O)(ClO₄)]路0.5H₂O (Ln = La鈥揘d, Sm), which are two-dimensional sheet structures, all other compounds are three-dimensional frameworks in which the layers are tethered together by BO₃ units found roughly perpendicular to the sheets. Furthermore, a change in product is observed depending on the reaction duration while holding all other synthetic variables constant. This report also demonstrates that lanthanide borates can be prepared in extreme acidic conditions.