Nanjing University of Technology, New-model Road, 5, Nanjing, 210000, P.R. China

摘要

Polyether chains have been successfully grafted onto the interlayer surface of a Dion-Jacobson-type layered perovskite, HLaNb2O7·xH2O, by a reaction between an n-decoxy-derivative of HLaNb2O7·xH2O and CH3(OCH2CH2)_mOH (1 ≤ m ≤ 4). After the reaction, the interlayer distance decreases from 2.73 nm to 1.58 (m = 1), 2.07 (m = 2), 2.28 (m = 3), and 2.69 (m = 4) nm. Solid-state ~(13)C CP/MAS NMR spectroscopy indicates that the CH3(OCH2CH2)_mO- groups are bound to the interlayer surface of HLaNb2O7·xH2O. The n-decoxy groups are completely removed by the reaction with CH3(OCH2CH2)_mOH (m = 2 and 3), while a part of the w-decoxy groups remain after the reaction with CH3(OCH2CH2)_mOH (m = 1 and 4). Upon treatment of the CH3(OCH2CH2)_mO-grafted HLaNb2O7· xH2O (m = 2 or 3) with a CH3(OCH2CH2)_mOH solution of LiClO4, the interlayer distance decreases further to 1.78 (m = 2) and 2.01 (m = 3) nm. Inductively coupled plasma emission spectrometry reveals the presence of lithium (0.22 (m = 2) and 0.24 (m = 3) per [LaNb2O7]). The presence of ClO_4~- ions is demonstrated by Raman spectroscopy, and the position of the v1(A1) band indicates the presence of isolated ClO_4~- ions in the interlayer space. After treatment with a LiClO4 solution, CH3(OCH2CH2)_mO-grafted HLaNb2O7·xH2O (m = 2 and 3) exhibits ionic conductivity, and no clear temperature dependence is observed.