Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
Dalton Trans. 2010 Mar 7;39(9):2293-300. doi: 10.1039/b912255a. Epub 2010 Jan 11.
Heterotrinuclear Fe(II)-Cu(II)-Fe(II) complexes Cu(FcTropOMe)(2)(H(2)O)(2)(2) (FcTropOMe = 5-ferrocenyl-2-methoxytropone) (1), Cu(FcTropNEt(2))(2)(2) (FcTropNEt(2) = 2-(N,N-diethylamino)-5-ferrocenyltropone) (2) and [Cu(FcTropNEt)(2)] (FcTropNEt = 2-(N-ethylamino)-5-ferrocenyltroponate) (3) were synthesized. In addition, a hexafluorophosphate salt of heterotrinuclear Fe(III)-Cu(II)-Fe(III) complex Cu(FcTropNEt)(2) (3(2+)) was successfully obtained as single crystals by electrochemical oxidation of 3. By comparing the X-ray structures and absorption spectra of dicationic complexes 1 and 2, the 2-(diethylamino)tropone ligand was found to induce a greater intramolecular charge transfer (CT) from ferrocenyl to tropone-Cu(II) moieties than the 2-methoxytropone ligand. On the other hand, 3(2+) showed a broad CT band in the near-infrared (NIR) region similar to 2, which can be assigned to a transition from troponato-Cu(II) to ferrocenium moieties. As for the magnetic properties of 3(2+)(PF(6)(-))(2), measurements of temperature dependence of magnetic susceptibility and ESR on the solid state and in solution revealed the presence of a strong ferromagnetic interaction (J(Fe-Cu) = +12.0 cm(-1)) between the low spin Fe(III) ion with S = 1/2 and Cu(II) ion with S = 1/2 despite a long distance pathway via the aminotroponato and cyclopentadienyl moieties. DFT calculations supported this intramolecular ferromagnetism, which is induced by a spin polarization mechanism through the pi-spacers.
合成了异核三核 Fe(II)-Cu(II)-Fe(II)配合物 Cu(FcTropOMe)(2)(H(2)O)(2)(2) (FcTropOMe = 5- 二茂铁基-2-甲氧基-2,4-戊二酮) (1)、Cu(FcTropNEt(2))(2)(2) (FcTropNEt(2) = 2-(N,N-二乙基氨基)-5-二茂铁基-2,4-戊二酮) (2) 和 [Cu(FcTropNEt)(2)] (FcTropNEt = 2-(N-乙基氨基)-5-二茂铁基-2,4-戊二酮) (3)。此外，通过 3 的电化学氧化成功获得了异核三核 Fe(III)-Cu(II)-Fe(III)配合物 Cu(FcTropNEt)(2) (3(2+)) 的六氟磷酸盐盐作为单晶。通过比较二价阳离子配合物 1 和 2 的 X 射线结构和吸收光谱，发现 2-(二乙氨基)戊二酮配体诱导的从二茂铁基到 tropone-Cu(II)部分的分子内电荷转移 (CT) 大于 2-甲氧基戊二酮配体。另一方面，3(2+) 在近红外 (NIR) 区域显示出宽 CT 带，类似于 2，可归因于 troponato-Cu(II) 到 ferrocenium 部分的跃迁。对于 3(2+)(PF(6)(-))(2) 的磁性性质，在固态和溶液中测量磁化率和 ESR 对温度的依赖性表明，尽管通过氨基戊二酮和环戊二烯基部分存在长距离途径，但低自旋 Fe(III)离子 S = 1/2 和 Cu(II)离子 S = 1/2 之间存在强铁磁相互作用 (J(Fe-Cu) = +12.0 cm(-1))。DFT 计算支持这种通过 pi-间隔物诱导的分子内铁磁性，这是通过自旋极化机制引起的。
