Induced self-assembly and Förster Resonance Energy Transfer Studies of Alkynylplatinum(II) Terpyridine Complex through interaction with water-soluble Poly(phenylene ethynylene sulfonate) and the proof-of-principle demonstration of this two-component ensemble for selective label-free detection of Human Serum Albumin (HSA)

Abstract

The interaction of conjugated polyelectrolyte, PPE-SO3 − , with platinum(II) complexes, [Pt(tpy)(C≡CC6H4CH2NMe3-4)](OTf)2 (1) and [Pt(tpy)(C≡C–CH2NMe3)](OTf)2 (2), has been studied by UV–vis, and steady-state and time-resolved emission spectroscopy. A unique FRET from PPESO3 − to the aggregated complex 1on the polymer chain with PtfflfflfflPt interactionhas been demonstrated, resulting in the growth of triplet metal-metal-to-ligand charge transfer (3MMLCT) emission in the nearinfrared (NIR) region. This two-component ensemble has been employed in a “proof-of-principle” concept for the sensitive and selective label-free detection of HSA by the emission spectral changes in the visible and NIR region, which have been ascribed to the disassembly of the polymer-metal complex aggregates upon the binding of PPE-SO3 − to HSA, leading to the decrease in FRET. The ensemble is found to have high selectivity towards HSA over a number of polyelectrolytes, proteins and small amino acids. This has been suggested to be a result of the extra stabilization gained from the PtfflfflfflPt and π–π interactions in addition to the electrostatic and hydrophobic interactions found in the polymer-metal complex aggregates. [1] Reference [1] C. Y. S. Chung and V. W. W. Yam, J. Am. Chem. Soc.,2011, 133, 18775-18784.