A novel double-stranded dinuclear copper(I) helicate having a photoluminescent CuI2N8 chromophore

Bis-(pyridinal)-ethylenediimine (L) affords [CuI2L2]X2 (X=ClO4− and PF6−). The X-ray crystal structure of the ClO4− salt shows that the cation [CuI2L2]2+ is a double-stranded helicate. The PF6− salt exhibits a single emission band (maxima, 540 nm) in solution at room temperature (quantum yield: 2×10−5 in methanol, 1×10−5 in CH2Cl2).