Anthracene-based ferrocenylselenoethers: syntheses, crystal structures, Cu(I) complexes and sensing property

Three novel anthracene-based ferrocenylselenoethers, 1,5-diselena-3-(anthracen-9'-ylmethyl)-[5]ferrocenophane (L3), 1,3-bis(ferrocenylseleno)-2-(anthracen-9'-ylmethyl) propane (L4) and N, N-bis[2-(ferrocenylselena)ethyl]-N-(anthracen-9'-ylmethyl)amine (L5) and their Cu(I) complexes, [Cu2Br2(L-2)(2)] (L2 = 1,1'-bis[2-(anthracen-9'-yloxy)-ethylseleno]ferrocene) (1), [Cu2I2(L-2)(2)] (2), [Cu2I2(L3)(2)]center dot 1.25CH(2)Cl(2) (3) and [Cu4I4(L5)(2)]center dot CH2Cl2 (4), have been prepared and structurally characterized. The X-ray crystallography analysis reveals that the complexes 1-3 possess a rhomboidal Cu2X2 core which is sandwiched by two L ligands through two Se atoms to form a dimer, while 4 owns a distorted cubane-like Cu4I4 core which is double-bridging linked by two L5 ligands via two Se atoms to produce a 1D loop chain. Each Cu(I) ion in 1-4 displays a distorted tetrahedral geometry. The unique structural feature in L3-L5 is the coexistence of a redox moiety (ferrocenyl) and a fluorescent chromogenic group (anthracenyl). In the cation sensing study, L3 and L4 present multiresponsive signals for Cu2+ and Hg2+, L5 for Cu2+, Zn2+ and Hg2+. The selectivity can be tuned by incorporating an additional donor N atom, and/or oxidation of the ferrocene unit.