Yoshimura Takashi, Nagata Kojiro, Nakano Motohiro
Radioisotope Research Center, Institute for Radiation Sciences, Osaka University, Suita 565-0871, Japan.
Core Facility Center, Osaka University, Toyonaka 560-0043, Japan.
Inorg Chem. 2024 Aug 12;63(32):14913-14923. doi: 10.1021/acs.inorgchem.4c01321. Epub 2024 Jul 29.
New pyrazine (pz)- and 4,4'-bipyridine (4,4'-bpy)-bridged octahedral hexanuclear rhenium(III) cluster dimers, [{Re(μ-S)Cl}(μ-L)] (L = pz, []; L = 4,4'-bpy, []), with 2 × 24 d-electrons {Re(24e)} were obtained in a single-step reaction via photoirradiation of [Re(μ-S)Cl] with L in a 2:1 ratio at room temperature. The {Re(23e)} dimers, [{Re(μ-S)Cl}(μ-L)] (L = pz, []; L = 4,4'-bpy, []), were synthesized through two-electron oxidation of [] and [], respectively. The single-crystal X-ray structures of [] and [] were determined, revealing structural distortion of the Re core of [] due to the Jahn-Teller effect. The cyclic voltammograms of [] and [] showed two steps of one-electron redox processes attributable to Re(23e)Re(24e)/{Re(24e)} and {Re(23e)}/Re(23e)Re(24e), respectively. The separation between the two redox potentials is small (0.056 V for [] and 0.039 V for []). The magnetic susceptibilities of [] and [] were almost temperature-independent, with values of 2.98 and 2.85 μ, respectively, indicating paramagnetism. These results suggest weak electronic interaction between two cluster units bridged by pz or 4,4'-bpy in the intercluster mixed valence state. The compounds [] and [] show photoluminescence in the near-infrared region at 296 K in the solid state.
新型吡嗪（pz）和4,4'-联吡啶（4,4'-bpy）桥连的八面体六核铼（III）簇二聚体，[{Re(μ-S)Cl}(μ-L)]（L = pz，[]；L = 4,4'-bpy，[]），具有2×24个d电子{Re(24e)}，是通过在室温下以2:1的比例用L对[Re(μ-S)Cl]进行光照射，在一步反应中获得的。{Re(23e)}二聚体[{Re(μ-S)Cl}(μ-L)]（L = pz，[]；L = 4,4'-bpy，[]）分别通过[]和[]的双电子氧化合成。测定了[]和[]的单晶X射线结构，揭示了由于 Jahn-Teller 效应导致[]的Re核结构畸变。[]和[]的循环伏安图分别显示了归因于Re(23e)Re(24e)/{Re(24e)}和{Re(23e)}/Re(23e)Re(24e)的两个单电子氧化还原过程步骤。两个氧化还原电位之间的间隔很小（[]为0.056 V，[]为0.039 V）。[]和[]的磁化率几乎与温度无关，值分别为2.98和2.85 μ，表明具有顺磁性。这些结果表明，在簇间混合价态中，由pz或4,4'-bpy桥连的两个簇单元之间存在弱电子相互作用。化合物[]和[]在296 K的固态下在近红外区域显示光致发光。
