A Luminescence Assay in the Red for the Detection of Hydrogen Peroxide and Glucose Based on Metal Coordination Polyelectrolyte-Induced Supramolecular Self-Assembly of Alkynylplatinum(II) Complexes.

A new sensing strategy towards hydrogen peroxide based on metal coordination polyelectrolyte-driven self-assembly of alkynylplatinum(II) 2,6-bis(benzimidazol-2'-yl)pyridine (bzimpy) complex was demonstrated. The cationic in situ-generated Ag(I)-thiocholine coordination polyelectrolytes were shown to induce the supramolecular self-assembly of anionic low-energy red-emissive alkynylplatinum(II) bzimpy complexes via non-covalent Pt(II)⋅⋅⋅Pt(II), electrostatic and π-π stacking interactions. The presence of hydrogen peroxide was shown to inhibit the formation of coordination polyelectrolytes and the coordination polyelectrolyte-induced self-assembly of platinum(II) complexes. The weakening of Pt(II)⋅⋅⋅Pt(II), electrostatic and π-π stacking interactions was supported by UV-vis absorption, emission, and resonance light scattering (RLS) studies. The present assay was also applied to probe glucose indirectly based on the enzymatic reaction of glucose oxidase on the substrate. Operating in a label-free manner, together with the low-energy red emission and large Stokes shift of alkynylplatinum(II) complexes, these features render the proposed design attractive for biological applications.