Probing the electronic communication of linear heptanickel and nonanickel string complexes by utilizing two redox-active [Ni2(napy)4]3+ moieties
作者:Shao-An Hua、Isiah Po-Chun Liu、Hasan Hasanov、Gin-Chen Huang、Rayyat Huseyn Ismayilov、Chien-Lan Chiu、Chen-Yu Yeh、Gene-Hsiang Lee、Shie-Ming Peng
DOI:10.1039/b923125k
日期:——
Two extended nickel string complexes, [Ni7(bnapy)4Cl2](Cl)2 (2) and [Ni9(bnapya)4Cl2](PF6)2 (3) (bnapy2− = 2,6-bis(1,8-naphthyridylamido)pyridine and bnapya3- = bis(6-(1,8-naphthyridylamido)pyridyl)amido), which possess two redox-active [Ni2(napy)4]3+ units, were synthesized and characterized. The electronic communication between the two redox-active units in both complexes can be investigated not only by magnetic measurements but also by analyzing the difference between two consecutive one-electron oxidation peaks (ΔE1/2) of 2 and 3. The antiferromagnetic coupling between the two [Ni2(napy)4]3+ fragments become weaker as the metal frameworks are elongated (J = −13.21 and −1.48 cm−1 for 2 and 3, respectively). Moreover, the ΔE1/2 values of 2 and 3 are 110 and 84 mV, respectively, which are smaller than that (300 mV) of their pentanickel analogue [Ni5(bna)4(Cl)2](PF6)2 (bna− = bisnaphthyridylamido) (1). These ΔE1/2 values indicate that the electronic communication decreases with increasing number of inner diamagnetic nickel ions in nickel string complexes.
两个延伸的镍串络合物,[Ni7(bnapy)4Cl2](Cl)2 (2) 和 [Ni9(bnapya)4Cl2](PF6)2 (3) (bnapy2− = 2,6-bis(1,8-naphthyridylamido) ) 吡啶和 bnapya3- = 双(6-(1,8-萘啶基酰胺基)吡啶基)酰胺基) 具有两个氧化还原活性 [Ni2(napy)4]3+ 单元,已合成并表征。两种复合物中两个氧化还原活性单元之间的电子通信不仅可以通过磁性测量来研究,还可以通过分析 2 和 3 的两个连续单电子氧化峰 (ΔE1/2) 之间的差异来研究。随着金属骨架的拉长,两个 [Ni2(napy)4]3+ 片段变得更弱(对于 2 和 3,分别为 J = -13.21 和 -1.48 cm−1)。此外,2和3的ΔE1/2值分别为110和84 mV,小于其五镍类似物[Ni5(bna)4(Cl)2](PF6)2 (bna− = 双萘啶酰氨基) (1)。这些 ΔE1/2 值表明电子通讯随着镍串复合物中内部反磁性镍离子数量的增加而减少。