Pseudo-polyrotaxanes: Cucurbituril-poly(pyridyl vinyelene) complexes showing enhanced fluorescence and selective sensing capabilities


Niamh Willis-Fox


Niamh Willis-Fox [1,2] and Timothy M. Swager [1]

Author Affiliation: 

1 Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, USA 2 School of Chemistry, Trinity College Dublin, College Green, Dublin 2, Ireland


Conjugated polymers (CPs) are excellent materials for (bio)-chemical sensing where efficient exciton migration in the polymer backbone leads to large sensitivity enhancements within the system. Despite this, the development of electron poor polymers for the detection of electron-rich analytes remains limited.1 This study examines the electron-poor, protonated CP; poly(pyridyl vinylene) (PPyV) and its capacity to sense electron-rich biomolecules. However, the poor solubility of this CP significantly limits its applications. To address this, we aim to exploit the ability of cucurbiturils (CBs) to act as molecular hosts. CBs are an exciting class of symmetrical macrocycle comprised of varying numbers of glycoluril units giving rise to two partially negatively charged carbonyl portals encapsulating a hydrophobic cavity.2 Thus, CBs exhibit excellent water solubility and selective binding of positively charged guest species.3 This work will demonstrate the synthesis of a novel CP-based pseudo polyrotaxane species by stringing CBs of varying sizes onto the protonated PPyV backbone, dramatically enhancing the fluorescence signal. The varying width of the CB pockets will be exploited to perform size exclusion sensing of biomolecules. This intriguing system will couple the electronic interactions of the CP-analyte with the size selectivity of the CB-analyte interactions to produce a highly discriminatory sensing platform. 1. S. Rochat and T. M. Swager, Angew. Chem. Int. Ed., 2014, 53, 9792. 2. K. I. Assaf and W. Nau, Chem. Soc. Rev., 2015, 44, 394. 3. L. Zhu, H. Yan, X. Wang and Y. Zhao, J. Org. Chem., 2012, 77, 10168.