SPECIATION OF AQUEOUS GOLD(III) CHLORIDES FROM ULTRAVIOLET VISIBLE ABSORPTION AND RAMAN RESONANCE RAMAN SPECTROSCOPIES
SPECIATION OF AQUEOUS GOLD(III) CHLORIDES FROM ULTRAVIOLET VISIBLE ABSORPTION AND RAMAN RESONANCE RAMAN SPECTROSCOPIES
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DOI：
10.1016/0016-7037(91)90332-y
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发表时间：
1991-03-01
影响因子：
5
通讯作者：
BROWN, GE
中科院分区：
文献类型：
--
作者：
PECK, JA;TAIT, CD;BROWN, GE
采用紫外/可见（UV/vis）吸收光谱和拉曼/共振拉曼（RR）光谱测定了室温和常压下一摩尔NaCl水溶液中金（III）的形态与pH的关系。紫外/可见光谱研究的溶液中金的浓度约为10(-4)M，而拉曼光谱研究的溶液中金的浓度约为10(-2)M。随着pH值的增加，Au（III）氯化物溶液的紫外/可见光谱中配体到金属电荷转移带的强度和位置的变化与氯化物被氢氧根配体取代一致。相同溶液的拉曼和RR光谱的数量、位置和强度的变化也与四配位Au（III）的第一个配位球中氯化物被氢氧根配体连续取代的情况一致，随着ph的增加。我们的拉曼和UV/vis数据与早期基于各种化学测量的物种形成预测基本一致。但证明了混合氯-羟基配合物比理论上估计的稳定常数所预测的更稳定。
Gold(III) speciation in a one molar NaCl aqueous solution at ambient temperature and pressure was determined as a function of pH using ultraviolet/visible (UV/vis) absorption and Raman/resonance Raman (RR) spectroscopies. Gold concentrations in the solutions studied by UV/vis spectroscopy were approximately 10(-4) M whereas those studied by Raman spectroscopy were approximately 10(-2) M. Changes in the intensity and positions of ligand-to-metal charge transfer bands in the UV/vis spectra of the Au(III) chloride solutions with increasing pH are consistent with replacement of chloride by hydroxide ligands. Changes in the number, position, and intensity of Raman and RR spectra of the same solutions are also consistent with successive replacement of chloride by hydroxide ligands in the first coordination sphere of four-coordinated Au(III) with increasing pH. Our Raman and UV/vis data are broadly consistent with earlier speciation predictions based on a variety of chemical measurements, but demonstrate that the mixed chloro-hydroxo complexes are more stable than predicted on the basis of theoretically estimated stability constants.