Coordination behaviour of 1-(3,2':6',3''-terpyridin-4'-yl)ferrocene: structure and magnetic and electrochemical properties of a tetracopper dimetallomacrocycle

The discrete coordination compound [Cu 4 Cl 8 ( 3 ) 4 (MeOH) 2 ] is obtained from the reaction of a chloroform solution of 1-(3,2':6',3''-terpyridin-4'-yl)ferrocene ( 3 ) with a methanol solution of CuCl 2 ; the single crystal structure of [{Cu 4 Cl 8 ( 3 ) 4 (MeOH) 2 } . 0.7CHCl 3 . 1.8MeOH] is described. Two {Cu 2 Cl 4 ( 3 ) 2 (MeOH)} units are connected by bridging chlorido ligands to generate a centrosymmetric tetranuclear molecule featuring face-to-face π-interactions between ferrocene units and between tpy domains. Intermolecular π-stacking of ferrocene and tpy units lead to quadruple-decker stacking motifs in the solid-state. The tetranuclear compound represents a pair of μ-Cl bridged Cu(II) dimers exhibiting a weak antiferromagnetic coupling via the bridging chlorido ligands. The redox behaviour of 3 has been investigated by cyclic voltammetry and spectroelectrochemistry; a ferrocenyl oxidation process is observed for [Cu 4 Cl 8 ( 3 ) 4 (MeOH) 2 ].