Unusual emission from norbornene derived phosphonate molecule--a sensor for Fe(III) in aqueous environment.

This communication describes the synthesis and characterization of norbornene derived phosphonates (NDP1 to NDP3). The unusual fluorescence of NDP1 is attributed to the difference between the positions of HOMO and LUMO wave functions that lead to the prevention of non-radiative relaxation pathways. Due to the significant non-radiative relaxation pathway, the control molecule NDP2 shows weak fluorescence whereas NDP3 shows no fluorescence at all. Similar experiments are carried out on NDPH1, the homopolymer of NDP1. Our hypothesis is further strengthened as there is no emission from NDPH1. The unusual fluorescence is utilized as a new fluorometric sensor that selectively detects Fe-III ions.