A New Sol−Gel Route to Aluminum Fluoride Phosphate Glasses: Mechanistic Investigations by NMR Spectroscopy
A New Sol−Gel Route to Aluminum Fluoride Phosphate Glasses: Mechanistic Investigations by NMR Spectroscopy
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DOI：
10.1021/cm050066z
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发表时间：
2005-05
影响因子：
8.6
通讯作者：
Long Zhang;C. C. Araujo-C.;H. Eckert
中科院分区：
文献类型：
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作者：
Long Zhang;C. C. Araujo-C.;H. Eckert
以氟磷酸二钠（Na2PO3F）和乳酸铝（Al(lact)3）水溶液为前驱体，采用溶胶-凝胶方法制备了均匀透明的氟化铝磷酸钠凝胶和玻璃。通过多核高分辨率液体和固态核磁共振技术监测从溶液到凝胶和最终玻璃的结构演变，提供对反应机理的详细了解。19F核磁共振结果表明，共价F−P键在这些溶液中是稳定的，并且在从溶胶到凝胶的缩聚过程中不受Al−O−P键形成的影响。随后在T bb0 100°C下对干凝胶进行退火，促进分子内氟从磷转移到铝，同时在加热时去除乳酸配体，从而产生最终产品氟化铝磷酸钠玻璃。在这些玻璃中，所有的氟都配位到八面体铝(Al(F，OP)6 u…
Homogeneous and transparent sodium aluminum fluoride phosphate gels and glasses were prepared by a novel single-step sol−gel route using aqueous solutions of di-sodium fluorophosphate (Na2PO3F) and aluminum lactate (Al(lact)3) as precursors. The structural evolution from the solution to the gel and the final glass is monitored by multinuclear high-resolution liquid and solid-state NMR techniques, providing detailed insight into the reaction mechanism. The 19F NMR results indicate that the covalent F−P bond is stable in these solutions and remains unaffected by the formation of Al−O−P linkages during the polycondensation process from the sol to the gel state. The subsequent annealing at T > 100 °C of the xerogel promotes intramolecular fluorine transfer from phosphorus to aluminum, concomitant with the removal of lactate ligands upon heating, resulting in sodium aluminum fluoride phosphate glasses as the final product. In these glasses, all of the fluorine is coordinated to octahedral aluminum (Al(F,OP)6 u...