A comparative study on reactions of n-alkylamines with tungstic acids with various W–O octahedral layers: Novel evidence for the “dissolution–reorganization” mechanism

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• 作者：Deliang Chen ; Tao Li ; Li Yin ; Xianxiang Hou ; Xiujun Yu ; Yang Zhang ; Bingbing Fan ; Hailong Wang ; Xinjian Li ; Rui Zhang ; Tiecui Hou ; Hongxia Lu ; Hongliang Xu ; Jing Sun ; Lian Gao
• 关键词：Inorganic– ; organic layered hybrid ; Tungstic acids ; Multilayers ; Crystal growth
• 刊名：Materials Chemistry and Physics
• 出版年：2011
• 出版时间：15 February 2011
• 年：2011
• 卷：125
• 期：3
• 页码：838-845
• 全文大小：1337 K

文摘

The aim of this paper was to provide a convincing experimental research to demonstrate a dissolution–reorganization mechanism for the formation of tungstate-based inorganic–organic hybrid nanobelts by comparatively investigating the reaction behaviors of H₂WO₄ and H₂W₂O₇·xH₂O with n-alkylamines (C_mH_2m+1NH₂, m = 4–10). The formation of tungstate-based hybrid nanobelts derived from the reactions between n-alkylamines and H₂WO₄ with single-octahedral W–O layers was investigated with a detailed comparison with those between n-alkylamines and H₂W₂O₇·xH₂O with double-octahedral W–O layers. H₂WO₄ and H₂W₂O₇·xH₂O reacted with n-alkylamines, respectively, in reverse-microemulsion-like media. The obtained products were characterized by XRD, FT-IR, TG–DTA and SEM. The results indicated that the products derived from H₂WO₄ and those from H₂W₂O₇·xH₂O were similar in compositions, microstructures and morphologies. The structural analysis indicated the products were tungstate-based inorganic–organic hybrid one-dimensional belts with highly ordered lamellar structures by alternately stacking organic n-alkylammonium bilayers and inorganic single-octahedral W–O layers. The n-alkyl chains in the above hybrid nanobelts from H₂WO₄ and H₂W₂O₇·xH₂O took on a bilayer arrangement with tilt angles of 65° and 74°, respectively. The similarities in the microstructures of the products from H₂W₂O₇·xH₂O and H₂WO₄ demonstrated that the double-octahedral W–O layers of H₂W₂O₇·xH₂O were decomposed during the reactions. The changes of inorganic W–O layers and the morphologic changes of the tungstic-acid precursors before and after the reactions corroborated the dissolution–reorganization mechanism.