Royal Society of Chemistry, Dalton Transactions, 40(43), p. 15212-15220, 2014
DOI: 10.1039/c4dt02126f
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In a study of multifunctional (‘hybrid’) molecular materials, with one function being spin-crossover and the second being reversible redox behaviour, we describe ferrocene-appended ligands and their d6 and d7 complexes trans-[FeII(FTP)2(NCS)2] (1), [CoII(FTTP)2](ClO4)2•2(MeCN) (2) and [FeII(FTTP)2](ClO4)2•Et2O (3) (where FTP = 4-(2-pyridyl)-1H-1,2,3-triazol-1-ylferrocene and FTTP = 4’-ferrocenyl-2,2’:6’,2’’-terpyridine). The structures, magnetism and solution electrochemistry are described. Complex 1 remains high-spin, 2 displays gradual, incomplete spin crossover and 3 remains low-spin between 350 – 2 K. The electrochemical results show that one-electron oxidations at the ferrocene group, located external to the coordination site, occur at more positive potentials than the ‘inner’ MII/III couple in 1 and 2, but not in 3, and this has implications for retaining and influencing spin transitions at the MII centres, in future.