Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, USA.
Inorg Chem. 2012 May 7;51(9):5264-9. doi: 10.1021/ic300191y. Epub 2012 Apr 16.
Charge fluctuations along the quasi-1D frameworks of M(x)V(2)O(5) bronzes have evinced much recent interest owing to the manifestation of colossal metal-insulator transitions and superconductivity. Depending upon the nature of the intercalating cation (M), distinctive geometries of the V(2)O(5) framework are accessible. Herein, we demonstrate an unprecedented reversible transformation between double-layered (δ) and tunnel (β) quasi-1D geometries for nanowires of a divalent vanadium bronze, Ca(x)V(2)O(5) (x ≈ 0.23), upon annealing-induced dehydration and hydrothermally induced hydration. Such a facile hydration/dehydration-induced interconversion between two prominent quasi-1D structures (accompanied by a change in charge-ordering motifs) has not been observed in the bulk and is posited to result from the ease of propagation of crystallographic slip processes across the confined nanowire widths for the δ → β conversion and the facile diffusion of water molecules within the tunnel geometries for the β → δ reversion.
由于在准一维框架的 M(x)V(2)O(5)青铜中出现了巨大的金属-绝缘体转变和超导现象，电荷波动引起了人们的极大兴趣。根据嵌入阳离子（M）的性质，可以获得 V(2)O(5)框架的不同几何形状。在这里，我们证明了在退火诱导脱水和水热诱导水合作用下，二价钒青铜 Ca(x)V(2)O(5)（x ≈ 0.23）的纳米线中，双层（δ）和隧道（β）准一维几何结构之间存在前所未有的可逆转变。在体相中尚未观察到这种简便的水合/脱水诱导的两种主要准一维结构之间的相互转化（伴随着电荷有序模式的变化），这被认为是由于在 δ → β 转变时易于在受限纳米线宽度上传播晶体滑移过程，以及在 β → δ 反转时水分子在隧道几何结构内的扩散容易所致。
