Ferrocenyl anthracenes: Synthesis and molecular structure

The synthesis of a series of ferrocenylanthracene derivatives is described, utilising the palladium catalysed coupling reaction of 1,1′-bis(chlorozincio)ferrocene with halo-anthracenes. Bis-1,1′-(9-anthracenyl)ferrocene (1) was characterised by single crystal X-ray diffraction and shows an eclipsed ferrocenyl geometry. X-ray crystallographic studies indicate that there are no clear stacking interactions of either an intra- or intermolecular nature between the anthracenyl rings in the structure. A series of 9- and 10-disubstituted ferrocenylanthracene derivatives has also been prepared. In each case the palladium catalyst (Pd(dppf)Cl₂) is recovered in a modified form, e.g. as the (dppf)PdBr(9-anthracenyl)] complex in the synthesis of bis-1,1′-(9-anthracenyl)ferrocene. The single crystal X-ray structure of one such palladium complex (dppf)PdBr-9-(10-chloroanthracenyl)] (15a) has been determined in a case where chloride/bromide exchange had occurred in the palladium complex intermediate. The potential application of compound 1 as synthon for the construction of a molecular sensing device is discussed. Cyclic voltammetry and fluorescence studies have been carried out for selected derivatives.