Functionalized Rhenium(I) Complexes with Crown Ether Pendants Derived from 1,10-Phenanthroline:  Selective Sensing for Metal Ions

A series of rhenium(I) tricarbonyl diimine complexes with crown ether pendants has been synthesized and characterized. The complexes showed selective and specific binding properties for various metal ions of different sizes and degrees of hardness and softness by variation of the cavity size and donor atoms of the crown ether. Upon binding of metal ions, obvious spectral changes were observed in the UV−vis spectra of the complexes and the emission intensity was found to be strongly enhanced. The X-ray crystal structure of one of the complexes has also been determined.