Synthesis, characterization, and physical properties of oligo(1-(N,N-dimethylamino)pyrrole)s and their doped forms, precursors of candidates for molecular flat-band ferromagnets
Synthesis, characterization, and physical properties of oligo(1-(N,N-dimethylamino)pyrrole)s and their doped forms, precursors of candidates for molecular flat-band ferromagnets
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DOI：
10.1039/c4tc02941k
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发表时间：
2015-04
影响因子：
6.4
通讯作者：
Y. Yamanoi;Kazuhiro Takahashi;T. Hamada;Norikazu Ohshima;Masashi Kurashina;Yohei Hattori;Tetsuro Kusamoto;R. Sakamoto;M. Miyachi;H. Nishihara
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文献类型：
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作者：
Y. Yamanoi;Kazuhiro Takahashi;T. Hamada;Norikazu Ohshima;Masashi Kurashina;Yohei Hattori;Tetsuro Kusamoto;R. Sakamoto;M. Miyachi;H. Nishihara
完全氧化的聚（1-（N，N-二甲基氨基）吡咯）（PDMAPyn+）是通过掺杂具有与原始吡咯相同数目的聚合物单元的阴离子而合成的，根据Aoki及其同事的理论计算（Phys. Rev. B：Condens.物质脱线物理，2003，68，140403; Phys. Rev. B：Condens.物质脱线物理，2010，82，235127）。在这里，我们描述了从二聚体（2）到十二聚体（12）的中性形式的寡（1-（N，N-二甲基氨基）吡咯）（ODMAPys）的合成。2-6的晶体结构（即，直到六聚体）通过单晶X射线分析测定。还报道了其氧化形式的化学和电化学形成。ODMAPys的电化学测量表明，低聚物4、6和8经历了2 e −氧化，而10和12则表现出准可逆的4 e −氧化。氧化形式保持相当的化学稳定性; 42+、62+、82+、104+和124+被分离为SbCl 6 −盐。中性形式是无色的（λmax = 240-270 nm），而氧化形式显示出强蓝色，λmax = 670-950 nm。EPR谱表明，在4.4K下，42+、62+和82+离子是反磁性的，而104+离子是顺磁性的。ODMAPys的这些物理性质与聚吡咯的常见物理性质不同，但与其预测的独特电子结构一致。
Fully oxidized poly(1-(N,N-dimethylamino)pyrrole)s (PDMAPyn+), which are synthesized through doping with anions with the same number of polymer units as the original pyrrole, have been proposed as candidates for molecular flat-band magnets from the theoretical calculations of Aoki and coworkers (Phys. Rev. B: Condens. Matter Mater. Phys., 2003, 68, 140403; Phys. Rev. B: Condens. Matter Mater. Phys., 2010, 82, 235127). Here we describe the synthesis of neutral forms of oligo(1-(N,N-dimethylamino)pyrrole)s (ODMAPys) from the dimer (2) to the dodecamer (12). The crystal structures of 2–6 (i.e., up to the hexamer) were determined by single crystal X-ray analysis. The chemical and electrochemical formation of their oxidized forms is also reported. Electrochemical measurements of the ODMAPys indicated that oligomers 4, 6, and 8 underwent 2e− oxidation, whereas 10 and 12 showed quasi-reversible 4e− oxidation. The oxidized forms maintained considerable chemical stability; 42+, 62+, 82+, 104+, and 124+ were isolated as SbCl6− salts. The neutral forms were colorless (λmax = 240–270 nm), whereas the oxidized forms exhibited strong blue color with λmax = 670–950 nm. EPR spectroscopy indicated that the dications 42+, 62+, and 82+ in the solid salts were intrinsically diamagnetic, but the tetracation of 104+ was paramagnetic at 4.4 K, which was supported by magnetic measurements. These physical properties of the ODMAPys are different from those common to polypyrroles, but consistent with their predicted unique electronic structures.