Multiresponsive Luminescent Cationic Cyclometalated Gold(III) Amphiphiles and Their Supramolecular Assembly
| Autor: | Vivian Wing-Wah Yam, Alan Kwun-Wa Chan, Maggie Ng, Ming-Yi Leung, Sammual Yu-Lut Leung, King-Chin Yim |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Ligand Supramolecular chemistry Stacking General Chemistry 010402 general chemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences Supramolecular assembly Hydrophobic effect Crystallography Colloid and Surface Chemistry chemistry Amphiphile Molecule Counterion |
| Zdroj: | Journal of the American Chemical Society. 141:19466-19478 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.9b10607 |
| Popis: | A new class of amphiphilic tridentate cyclometalated gold(III) complexes has been designed and synthesized as luminescent supramolecular building blocks. Positively charged trimethylammonium (-CH2NMe3+) containing alkynyl ligands have been incorporated to introduce the electrostatic interactions. The X-ray crystal structures of two of the complexes have been determined, and the existence of π-π interactions between molecules has been observed. Steady-state and time-resolved absorption and emission studies have been carried out to investigate the nature of the excited states. The complexes are found to exhibit self-assembly properties with the assistance of π-π stacking and hydrophobic interactions and possibly weak Au···Au interaction, resulting in notable emergence of low-energy absorption bands and luminescence changes. The presence of a large hydrophobic moiety is found to be crucial for the formation of aggregates, especially in polar media where hydrophobic interactions play an important role. The nature of the counterion has been shown to have a significant effect on the extent of self-assembly in different media. Upon aggregation, nanofibers are formed in polar media, while nanorods are observed in nonpolar media in one of the representative complexes. Interestingly, a small modification on the alkynyl ligand resulted in the formation of nanoribbons instead. Intriguing luminescence mechanochromic properties have also been observed. This orthogonal and rational molecular design strategy has been shown to be effective in the construction of gold(III)-based smart and multiresponsive materials. |
| Databáze: | OpenAIRE |
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