Zhang Long, de Araujo Carla C, Eckert Hellmut
Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, D-48149 Münster, Germany.
J Phys Chem B. 2007 Sep 6;111(35):10402-12. doi: 10.1021/jp072725w. Epub 2007 Aug 15.
The local structure of Na-Al-P-O-F glasses, prepared by a novel sol-gel route, was extensively investigated by advanced solid-state NMR techniques. 27Al{19F} rotational echo double resonance (REDOR) results indicate that the F incorporated into aluminophosphate glass is preferentially bonded to octahedral Al units and results in a significant increase in the concentration of six-coordinated aluminum. The extent of Al-F and Al-O-P connectivities are quantified consistently by analyzing 27Al{31P} and 27Al{19F} REDOR NMR data. Two distinct types of fluorine species were identified and characterized by various 19F{27Al}, 19F{23Na}, and 19F{31P} double resonance experiments, which were able to support peak assignments to bridging (Al-F-Al, -140 ppm) and terminal (Al-F, -170 ppm) units. On the basis of the detailed quantitative dipole-dipole coupling information obtained, a comprehensive structural model for these glasses is presented, detailing the structural speciation as a function of composition.
通过一种新型溶胶 - 凝胶法制备的Na - Al - P - O - F玻璃的局部结构，采用先进的固态核磁共振技术进行了广泛研究。27Al{19F}旋转回波双共振（REDOR）结果表明，掺入铝磷酸盐玻璃中的F优先与八面体Al单元键合，并导致六配位铝的浓度显著增加。通过分析27Al{31P}和27Al{19F} REDOR核磁共振数据，一致地量化了Al - F和Al - O - P连接的程度。通过各种19F{27Al}、19F{23Na}和19F{31P}双共振实验，鉴定并表征了两种不同类型的氟物种，这些实验能够支持将峰归属于桥连（Al - F - Al，-140 ppm）和末端（Al - F，-170 ppm）单元。基于所获得的详细定量偶极 - 偶极耦合信息，提出了这些玻璃的综合结构模型，详细说明了结构形态与组成的函数关系。
