The author of 《A delocalized cobaltoviologen with seven reversibly accessible redox states and highly tunable electrochromic behaviour》 were Mansoor, Iram F.; Wozniak, Derek I.; Wu, Yilei; Lipke, Mark C.. And the article was published in Chemical Communications (Cambridge, United Kingdom) in 2020. Formula: C20H14N4 The author mentioned the following in the article:
CoII mediates electronic coupling between two N-Me-pyridinium-terpyridine ligands that are related to redox-active N,N-dialkyl-4,4′-bipyridinium dications (viologens). Borderline Class II/III electronic delocalization imparts the cobaltoviologen complex with distinct electronic properties (e.g., 7 accessible redox states) relative to those of viologens, leading to enhanced electrochromism. After reading the article, we found that the author used 4′-(4-Pyridyl)-2,2′:6′,2”-terpyridine(cas: 112881-51-3Formula: C20H14N4)
4′-(4-Pyridyl)-2,2′:6′,2”-terpyridine(cas: 112881-51-3) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. Formula: C20H14N4The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds.