Mian Mohammad Rasel, Wakizaka Masanori, Yoshida Takefumi, Iguchi Hiroaki, Takaishi Shinya, Afrin Unjila, Miyamoto Tatsuya, Okamoto Hiroshi, Tanaka Hisaaki, Kuroda Shin-Ichi, Breedlove Brian K, Yamashita Masahiro
Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aramaki, Sendai 980-8578, Japan.
Department of Advanced Material Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan.
Dalton Trans. 2021 Feb 9;50(5):1614-1619. doi: 10.1039/d0dt03848b.
The Pd(iii) oxidation state is unusual and unstable since it strongly tends to disproportionate. We synthesized the quasi-one-dimensional (1D) halogen-bridged Pd(iii)-Cl complex [Pd(dabdOH)2Cl]Cl2 (1-Cl; dabdOH = (2S,3S)-2,3-diaminobutane-1,4-diol) with multiple hydrogen bonds. From single-crystal X-ray diffraction, the bridging Cl- ions were located at the midpoint of the Pd-Cl-Pd moieties in the 1D chains, indicating that the Pd ions are in a Pd(iii) average valence (AV) state. Moreover, bright spots for the Pd(iii) dz2 orbitals in the upper Hubbard band above the Fermi level were observed every ∼5 Å using scanning tunnelling microscopy. These results clearly indicate that the Pd ions are in a Pd(iii) AV state in 1-Cl. In addition, 1-Cl has the highest thermal stability (470 K) among the Pd(iii) complexes reported and the highest electrical conductivity (0.6 S cm-1 at 300 K) among the 1D Pd-Cl chains reported so far.
钯（III）氧化态并不常见且不稳定，因为它极易发生歧化反应。我们合成了具有多个氢键的准一维（1D）卤素桥连钯（III）-氯配合物[Pd(dabdOH)₂Cl]Cl₂（1-Cl；dabdOH = (2S,3S)-2,3-二氨基丁烷-1,4-二醇）。通过单晶X射线衍射，桥连Cl⁻离子位于一维链中Pd-Cl-Pd部分的中点，这表明钯离子处于钯（III）平均价态（AV）。此外，使用扫描隧道显微镜在费米能级以上的上哈伯德带中每隔约5 Å观察到钯（III）dz²轨道的亮点。这些结果清楚地表明，1-Cl中的钯离子处于钯（III）AV态。此外，1-Cl在已报道的钯（III）配合物中具有最高的热稳定性（470 K），在迄今为止报道的一维Pd-Cl链中具有最高的电导率（300 K时为0.6 S cm⁻¹）。
