在固态下捕获水解产物：环境条件下 pH 值对铀方酸酯的影响。

Capturing hydrolysis products in the solid state: effects of pH on uranyl squarates under ambient conditions.

机构信息

Department of Chemistry, The George Washington University, 725 21st St. NW, Washington, DC 20052, USA.

出版信息

Inorg Chem. 2010 Oct 4;49(19):8668-73. doi: 10.1021/ic1000792.

PMID:20222717

Abstract

Two uranyl squarates, (UO(2))(6)(C(4)O(4))(3)(OH)(6)O(2)·9H(2)O·4NH(4) (1; a = 16.6897(7) Å, cubic, I23) and (UO(2))(C(4)O(4))(OH)(2)·2NH(4) (2; a = 8.5151(4), b = 15.6822(8), c = 7.3974, orthorhombic, Pbcm), have been synthesized from ambient aqueous solutions as a function of pH. Oligomerization of the uranyl cation from monomeric pentagonal bipyramids (pH < 5) to [(UO(2))(3)O(OH)(3)] trimers (5 < pH < 8) in 1 and ultimately (UO(2))(OH)(2) chains (7 < pH < 8) in 2 is observed. This evolution of speciation versus pH is consistent with what has been observed in solution and thus may be represented by the uranyl hydrolysis equilibrium, mUO(2)(2+) + nH(2)O ↔ [(UO(2))(m)(OH)(n)](2m - n) + nH(+). Structural systematics, physical properties, and a discussion of species selectivity by squarate anions are presented.

摘要

两种铀酰方酸酯，（UO(2))(6)(C(4)O(4))(3)(OH)(6)O(2)·9H(2)O·4NH(4) (1; a = 16.6897(7) Å, cubic, I23) 和 (UO(2))(C(4)O(4))(OH)(2)·2NH(4) (2; a = 8.5151(4), b = 15.6822(8), c = 7.3974, orthorhombic, Pbcm)，已通过调节 pH 值从环境水溶液中合成。在 1 中，观察到铀酰阳离子从单体五边形双锥（pH < 5）到[(UO(2))(3)O(OH)(3)]三聚体（5 < pH < 8）的聚合，最终到 2 中(UO(2))(OH)(2)链（7 < pH < 8）的聚合。这种物种与 pH 值的演变与在溶液中观察到的一致，因此可以用铀酰水解平衡来表示，mUO(2)(2+) + nH(2)O ↔ [(UO(2))(m)(OH)(n)](2m - n) + nH(+)。本文介绍了结构系统性、物理性质以及方酸根阴离子对物种选择性的讨论。