Functional phosphorus-containing polymers and their potential application as "turn-on" fluorescent sensors

Introduction. The development of macromolecules featuring p-block elements in the backbone is  of considerable interest due to the unique oxidation states and coordination numbers that heteroatoms impart.  These... [ view full abstract ]

Introduction.

The development of macromolecules featuring p-block elements in the backbone is  of considerable interest due to the unique oxidation states and coordination numbers that heteroatoms impart.  These novel materials possess unique chemical, semi-conducting, optoelectronic and physical properties. Thus, they are of potential interest for numerous specialty applications.

Results and Discussion.

This presentation will focus on two functional phosphorus-containing polymers that have been developed in our laboratory: poly(methylenephosphine) (PMP) and poly(p-phenylenediethynylene phosphine) (PPYP). The synthetic procedures used to access these macromolecules will be outlined along with their basic properties. A focus of the presentation will be on the photophysical properties of PMPs and PPYPs. The observation that PMPs bearing C-substituents as chromophores (e.g. Ar = Naphyl, phenanthryl, etc.) are non-emissive unless the phosphorus moiety is functionalized is quite interesting. In particular, oxidation to the phosphine oxide results in a "turn-on" fluorescence, the intensity of which is dependent upon the degree of oxidation. Likewise, PPYP shows a similar "turn-on" fluorescence, however, in this case the sensitivity appears to be very selective to the analyte. A series of PPYPs have been prepared and the fluorescence quantum yields are highly dependent upon the structure of the conjugated spacer moiety. Finally, the  potential to use PPYPs as selective sensors towards certain analytes which may be either metals or non-metals will be discussed.