Protamine-Induced Supramolecular Self-Assembly of Red-Emissive Alkynylplatinum(II) 2,6-Bis(benzimidazol-2'-yl)pyridine Complex for Selective Label-Free Sensing of Heparin and Real-Time Monitoring of Trypsin Activity.

A label-free detection assay is developed based on the design and synthesis of a new anionic alkynylplatinum(II) 2,6-bis(benzimidazol-2'-yl)pyridine complex with water-soluble pendants. With the aid of electrostatic interaction and noncovalent metal-metal and π-π stacking interactions, protamine is shown to induce supramolecular self-assembly of platinum(II) complexes with drastic UV-vis absorption and red emission changes. On the basis of the strong binding affinity of protamine and heparin, the ensemble has been further employed to probe heparin by monitoring the spectroscopic changes.

Platinum(II)-Based Supramolecular Scaffold-Templated Side-by-Side Assembly of Gold Nanorods through Pt⋅⋅⋅Pt and π-π Interactions.

The side-by-side assembly of gold nanorods (GNRs) was shown to be directed by the supramolecular scaffolds formed by sulfonate-containing alkynylplatium(II) terpyridine complexes. Driven by Pt⋅⋅⋅Pt and π-π stacking interactions, the Pt complex has a high propensity to assemble in water with the head-to-tail stacking arrangement to construct supramolecular scaffolds, in which the sulfonate groups on the terpyridine ligand at the peripheral position preferentially bind to the sides of the GNRs. The extent of the assembly of the GNRs into ladder rung-like nanostructures can be modulated by the concentration of the Pt complex.

Molecular Engineering of Platinum(II) Terpyridine Complexes with Tetraphenylethylene-Modified Alkynyl Ligands: Supramolecular Assembly via Pt···Pt and/or π-π Stacking Interactions and the Formation of Various Superstructures.

A series of platinum(II) terpyridine complexes with tetraphenylethylene-modified alkynyl ligands has been designed and synthesized. The introduction of the tetraphenylethylene motif has led to aggregation-induced emission (AIE) properties, which upon self-assembly led to the formation of metal-metal-to-ligand charge transfer (MMLCT) behavior stabilized by Pt···Pt and/or π-π interactions. Tuning the steric bulk or hydrophilicity through molecular engineering of the platinum(II) complexes has been found to alter their spectroscopic properties and result in interesting superstructures (including nanorods, nanospheres, nanowires, and nanoleaves) in the self-assembly process.

Simple and Versatile Preparation of Luminescent Amphiphilic Platinum(II)-containing Polystyrene Complexes With Transformable Nanostructures Assisted by Pt⋅⋅⋅Pt and π-π Interactions.

Platinum(II)-containing polystyrene (PS) complexes have been synthesized by dehydrohalogenation of α-alkyne-PS and chloroplatinum(II) precursors with different functionalities on the terpyridine ligands. Through modulation of the hydrophilicity/hydrophobicity of the terpyridine ligands and hence the overall amphiphilicity of the complexes, the complexes can undergo self-assembly into various superstructures with remarkable luminescence properties in different solution mixtures, as revealed by electron microscopy, UV/Vis absorption and emission spectroscopy. Pt⋅⋅⋅Pt and/or π-π interactions among the platinum(II) terpyridine moieties are found to play substantial roles in the stabilization of the superstructures and the turn-on/off of the triplet metal-metal-to-ligand charge transfer ( MMLCT) emission of the complexes.