Design, Synthesis, And Properties Study Of Organometallic Self-Assembled Systems Based On Platinum-Acetylide Unit

Platinum-acetylide unit is an important class of organometallic system due to their wide application in various fields such as organic light emitting diodes, vapochromic materials, and solar cells. Among them, platinum-acetylide complexes have received considerable attention due to their intriguing spectroscopic properties and tunable intermolecular Pt Pt and π-π stacking interactions. However, although a large number of platinum-acetylide complexes have been explored, most of them are confined to the study of their structures and luminescence properties in the solid state. Their aggregation behavior in solution is relatively unexplored. Base on our interest in the construction of novel alkynylplatinum(Ⅱ) complexes, this paper focus on the design and synthesis of alkynylplatinum(Ⅱ) complexes with different sizes and shapes as well as the study of their self-assembly behavior in solution. By combination of Pt Pt and π-π stacking interactions with other non-covalent interactions such as hydrophobic-hydrophobic interaction and coordination-driven self-assembly, we have constructed a variety of stimuli-responsive gels and nanostructures.Chapter one, this chapter focus on the introduction of the structure, property, and their applications of alkynylplatinum(Ⅱ) complexes, especially the self-assembly behavior of alkynylplatinum(Ⅱ) polypyridyl complexes in solution and their research progress in supramolecular metallogels, host-guest chemistry, and biosensor.Chapter two, we designed and synthesized a series of π-conjugated star-shaped and branched complexes comprising alkynylplatinum(Ⅱ) unit as bridge. Moreover, their spectroscopic properties and aggregation behavior were investigated in silution. It is found that the structure of the conjugated backbone and the existence of amide units played an important role during the aggregation process. For instance, the complexes decorated with amide units were able to self-assemble into ordered nanostructures and stable metallogels. However, the complexes without the amide units did not have these properties.Chapter three, we report the synthesis of linear and Y-shaped amphiphilic platinum-acetylide complexes decorated with temperature-responsive hydrophilic oligoether dendrons at one end. It was found that Y-shaped complexes were able to self-assemble into stable supramolecular metallogels at room temperature. Unlike the conventional supramolecular gels, the resulting metallogels diaplayed multiphase transitions behavior triggered by the single stimuli. Moreover, by taking advantage of temperature-responsive property of the metallogel, the controlled release of fluorescein sodium at physiological temperature was successfully realized.Chapter four, by combination of Pt…Pt and π-π stacking interactions with coordination-driven self-assembly, we have constructed a novel supramolecular metallacycle which displayed vapochromic behavior. Importantly, the obtained vapochromic system features not only high selectivity but also ultra-stability. Further investigation revealed that the chair conformation of the metallacyclic scaffold facilitates the formation of intermolecular Pt…Pt and π-π stacking interactions, thus allowing such a highly stable vapochromic system.Chapter five, a new family of alkynylplatinum(II) bzimpy-functionalized supramolecular metallacycles with different shapes and sizes were successfully prepared through coordination-driven self-assembly. Interestingly, these novel metallacycles displayed switchable emission accompanying with the enhancement of intermolecular Pt…Pt and π-π stacking interactions. Moreover, one metallacycle was able to spontaneously self-assemble into stable metallogel at room temperature without heating-cooling process. More importantly, the obtained metallogel was selectively responsive to the aromatic complexes.Chapter six, we designed and constructed a new family of 60° dendritic dipyridyl donors, from which two novel triangular metallodendrimers were successfully prepared via coordination-driven self-assembly. Moreover, all the obtained triangular metallodendrimers were well characterized by multiple nuclear (1H and 31P) NMR spectroscopy, CSI-TOF-MS, and molecular simulation. Interestingly, it was found that first- and second-generation metallodendrimers were able to hierarchically self-assemble into the different nanostructures under the similar condition.