AbstractNovel redox‐active hexaguanidine molecules with multiple redox states were synthesized by connecting three o‐diguanidinobenzene units. In 2,3,6,7,14,15‐hexaguanidino‐triptycenes, the three redox‐active o‐diguanidinobenzene units are connected through C−C bonds to the sp3‐hybridized bridgehead C atoms, and in 2,3,6,7,10,11‐hexaguanidino‐triphenylenes they are directly connected. The connectivity difference leads to different electronic coupling between the three redox‐active o‐diguanidinobenzene units, with homoconjugation being present in the triptycene, but not in the triphenylene compounds. Motivated by the appearance of an intense low‐energy electronic transition, we especially analysed the effect of homoconjugation on the electronic structure and charge delocalization in the dicationic redox state of the triptycene derivatives. Then, several trinuclear high‐spin cobalt (and copper) complexes were synthesized with the triphenylene and triptycene ligands, and the magnetic coupling and redox properties analysed. By choice of the coligands (hexafluoroacetylacetonate, trifluoroacetylacetonate and acetylacetonate), oxidation could be switched between metal‐ and ligand‐centered redox events, leading to drastic changes in the magnetic or optical properties, especially as a consequence of homoconjugation in the triptycene derivatives.
摘要通过连接三个邻二胍基苯单元,合成了具有多种氧化还原状态的新型氧化还原活性六胍分子。在 2,3,6,7,14,15-六胍基三苯乙烯中,三个具有氧化还原活性的邻二胍基苯单元通过 C-C 键与 sp3 杂化桥头 C 原子相连,而在 2,3,6,7,10,11-六胍基三苯乙烯中,它们是直接相连的。连接性的差异导致三个具有氧化还原作用的邻二胍基苯单元之间产生不同的电子耦合,在三庚烯化合物中存在同源共轭,而在三亚苯化合物中则不存在。由于出现了强烈的低能电子转变,我们特别分析了同共轭作用对三庚烯衍生物二阳离子氧化还原态的电子结构和电荷分离的影响。然后,我们用三亚苯和三庚烯配体合成了几种三核高自旋钴(和铜)配合物,并分析了它们的磁耦合和氧化还原特性。通过选择配体(六氟乙酰丙酮酸盐、三氟乙酰丙酮酸盐和乙酰丙酮酸盐),氧化作用可以在以金属为中心和以配体为中心的氧化还原事件之间切换,从而导致磁性或光学性质的急剧变化,尤其是三庚烯衍生物中的同位共轭作用。