Platinum(II)-Based Host-Guest Coordination-Driven Supramolecular Co-Assembly Assisted by Pt···Pt and π-π Stacking Interactions: A Dual-Selective Luminescence Sensor for Cations and Anions.

A cationic water-soluble dipicolylamine (DPA)-containing alkynylplatinum(II) terpyridine complex has been synthesized and employed as a dual-selective probe for the detection of cations and anions. The complex was shown to exhibit a strong binding affinity toward Zn2+, whereas the zinc-bound adduct was found to demonstrate the capability of recognizing pyrophosphate (PPi). As evidenced by molecular modeling and various spectroscopic and spectrometric studies, including HR-ESI mass spectrometry, NMR spectroscopy, PXRD measurements, and UV-vis absorption and emission spectroscopy, a PPi anion was found to be capable of bridging two zinc-bound complex molecules in a clip-shaped fashion, which was further oligomerized through intermolecular Pt···Pt and π-π stacking interactions to form nanofibers with a hexagonal columnar phase. This work provides important insights into not only the construction of aesthetically pleasing supramolecular architectures but also the multifunctional probes, which offer great promise to the fields of biosensing and chemical sensing.

Toward the Design of Phosphorescent Emitters of Cyclometalated Earth-Abundant Nickel(II) and Their Supramolecular Study.

A series of cyclometalating tridentate N^C^N and tetradentate N^C^N^O ligand-containing complexes of earth-abundant nickel(II) has been designed and synthesized. Among them, the carbazolylnickel(II) complex demonstrates, for the first time, an orange color room-temperature luminescence. Such a complex is also found to exhibit intense luminescence with excited state lifetimes in the submicrosecond regime at 77 K, suggesting the triplet nature of the emissive state. Meanwhile, the self-assembly property of the tetradentate ligand-containing nickel(II) complex in solution has been investigated. Owing to its nearly perfect square planar geometry, as evidenced by X-ray crystal structure determination, it is found to exhibit self-assembly properties with the aid of π-π interactions and possibly weak Ni···Ni interactions, which have been supported by DFT calculations and NCI plot. Indeed, the ground-state aggregation behavior of this complex has been confirmed by concentration-dependent UV-vis absorption spectroscopy. Moreover, in the solution-induced aggregation studies, upon the addition of nonsolubilizing solvents, the emergence of low-energy absorption bands has been realized, and such a complex is found to demonstrate interesting self-assembly behaviors to offer well-defined and highly ordered supramolecular architectures.

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 PtII 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 PtII complex. The Pt⋅⋅⋅Pt interaction-assisted formation of the scaffolds and its directed assembly of GNRs were characterized by UV/Vis spectroscopy, quantum-chemical modeling, electron microscopy, energy dispersed X-ray (EDX) analysis, and SERS. This work provides insights for the construction of higher-ordered nano-assemblies using both Pt⋅⋅⋅Pt interactions and template-directed approaches.