Formation of p-phenylenediamine-crown ether-[PMo12O40]4- salts.
Formation of p-phenylenediamine-crown ether-[PMo12O40]4- salts.
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DOI：
10.1021/ic060857i
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发表时间：
2006-09
影响因子：
4.6
通讯作者：
T. Akutagawa;D. Endo;H. Imai;S. Noro;L. Cronin;Takayoshi Nakamura
中科院分区：
文献类型：
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作者：
T. Akutagawa;D. Endo;H. Imai;S. Noro;L. Cronin;Takayoshi Nakamura
电子从对苯二胺（PPD）的电子供体转移到（H+）3[PMo12O40]3-的电子受体，形成了一个单电子还原的Keggin簇[PMo12O40]4-，具有S = 1/2的自旋，而质子从（H+）3[PMo12O40]3-的质子供体转移到PPD的质子受体，产生了4-氨基苯胺（HPPD+）和对苯二胺（H2PPD2+）的单质子和双质子阳离子。通过在结晶过程中引入冠醚受体，成功地将（HPPD+）（冠醚）和/或（H2PPD2+）（冠醚）的超分子阳离子引入到（H2PPD2+）2([12]冠-4)4[PMo12O40]4-(1)、（HPPD+）4([15]冠-5)4[PMo12O40]4-(2)和（HPPD+）2(H2PPD2+)([18]冠-6)4[PMo12O40]4-(3)三种新的α -[PMo12O40]4-盐中作为反阳离子。PPD的质子化状态和超分子阳离子的分子组装结构取决于冠醚的大小。在盐3中，HPPD+和H2PPD2+的一种新型混合质子化状态被证实在阳离子结构中络合。根据阳离子结构的变化，盐1的阴离子排列由二维层转变为盐2和盐3的孤立簇。盐1-3的磁化率随温度的变化与[PMo12O40]4-的孤立自旋排列一致。在[PMo12O40]4-簇中，盐1-3的电子能谱显示了从五价Mo(V)到六价Mo（VI）离子的价间光学跃迁。盐2的温度相关电子自旋共振谱揭示了60 K时S = 1/2自旋的离域-局域跃迁。[PMo12O40]4-簇的自旋定位在60 K以下的特定Mo(V)位点上，其活化能为0.015 eV。
Electron transfer from the electron donor of p-phenylenediamine (PPD) to the electron acceptor of (H+)3[PMo12O40]3- forms a one-electron-reduced Keggin cluster of [PMo12O40]4-, bearing a S = 1/2 spin, while proton transfer from the proton donor of (H+)3[PMo12O40]3- to the proton acceptor of PPD yielded mono- and diprotonated cations of 4-aminoanilinium (HPPD+) and p-phenylenediammonium (H2PPD2+). By introduction of crown ether receptors during the crystallization process, supramolecular cations of (HPPD+)(crown ethers) and/or (H2PPD2+)(crown ethers) were successfully introduced into three new alpha-[PMo12O40]4- salts of (H2PPD2+)2([12]crown-4)4[PMo12O40]4- (1), (HPPD+)4([15]crown-5)4[PMo12O40]4- (2), and (HPPD+)2(H2PPD2+)([18]crown-6)4[PMo12O40]4- (3) as the countercation. The protonated states of PPD and molecular-assembly structures of the supramolecular cations depended on the size of the crown ethers. In salt 3, a novel mixed-protonated state of HPPD+ and H2PPD2+ was confirmed to be complexed in the cation structure. According to the changes in the cation structures, the anion arrangements were modulated from those of the two-dimensional layer for salt 1 to the isolated cluster for salts 2 and 3. The temperature-dependent magnetic susceptibilities of salts 1-3 were consistent with the isolated spin arrangements of [PMo12O40]4-. The electronic spectra of salts 1-3 indicated the intervalence optical transition from pentavalent Mo(V) to hexavalent Mo(VI) ions within the [PMo12O40]4- cluster. Temperature-dependent electron spin resonance spectra of salt 2 revealed the delocalization-localization transition of the S = 1/2 spin at 60 K. The spin on the [PMo12O40]4- cluster was localized on a specific Mo(V) site below 60 K, which was thermally activated with an activation energy of 0.015 eV.