Self-Assembled Architectures of Alkynylplatinum(II) Amphiphiles and Their Structural Optimization: A Balance of the Interplay Among Pt···Pt, π-π Stacking, and Hydrophobic-Hydrophobic Interactions.

A series of alkynylplatinum(II) terpyridine complexes with triethylene glycol units was synthesized, and their self-assembly properties were investigated in solution by UV-vis absorption, emission, and 1H NMR spectroscopy. The aggregation behaviors of several water-soluble complexes were investigated in aqueous media. Some of them were found to give rise to uniform fibers, suggesting the important role that triethylene glycol units has in regulating their self-assembly properties. Further modifications of these structures through the incorporation of alkyl chains and changes in counter-anions have rendered the complexes more amphiphilic in nature, and the effect of their alkyl chain lengths was studied and optimized. The distinguishable color and spectral changes upon variations in solvent compositions might have potential applications in developing colorimetric and luminescent probes for the detection of microenvironment change. Furthermore, an optimum chain length, i.e., n-butyl chain, is required for the formation of stable and ordered nanostructures. This represents a delicate balance among Pt···Pt, π-π stacking, and hydrophobic-hydrophobic interactions and provides guiding principles into the construction of supramolecular materials with practical applications.