title: Effect of pH and reaction time on the structures of early lanthanide(III) borate perchlorates.
abstract: Reactions of LnCl(3)·6H(2)O (Ln = La-Nd, Sm, Eu), concentrated (11 M) perchloric acid, and molten boric acid result in the formation of four different compounds. These compounds are Ln[B(8)O(10)(OH)(6)(H(2)O)(ClO(4))]·0.5H(2)O (Ln = La-Nd, Sm), Pr[B(8)O(11)(OH)(4)(H(2)O)(ClO(4))], Ln[B(7)O(11)(OH)(H(2)O)(2)(ClO(4))] (Ln = Pr, Nd, Sm, and Eu), and Ce[B(8)O(11)(OH)(4)(H(2)O)(ClO(4))]. 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[B(8)O(10)(OH)(6)(H(2)O)(ClO(4))]·0.5H(2)O (Ln = La-Nd, Sm), which are two-dimensional sheet structures, all other compounds are three-dimensional frameworks in which the layers are tethered together by BO(3) 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.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Polinski
authors.forename: Shuao
authors.initials: S
authors.lastname: Wang
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Alekseev
authors.forename: Justin N
authors.initials: JN
authors.lastname: Cross
authors.forename: Wulf
authors.initials: W
authors.lastname: Depmeier
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt