Design and preparation of platinum-acetylide organogelators containing ethynyl-pyrene moieties as the main skeleton

A series of new platinum-acetylide complexes containing ethynyl-pyrene moieties as the main skeleton were synthesized and characterized. The investigation of the absorption and emission spectra of these complexes revealed that the extension of the molecular size with the introduction of different numbered platinum-acetylide fragments can efficiently tune the absorption and emission bands from the UV to the longer wavelength region. Moreover, the gelation properties of these complexes were investigated by the "stable-to-inversion-of-a-test-tube" method. Most newly designed platinum-acetylide compounds presented a stable gel-formation property in some of the tested solvents. The morphology of the xerogels was investigated by scanning electron microscopy (SEM). Furthermore, the concentration- and temperature-dependent absorption and emission properties of these complexes were investigated, which support the formation of J-type assemblies during the aggregation process. More importantly, it was found that the complexes 4 a-C6, 4 a, and 4 a-C18 with four platinum-acetylide fragments presented potential applications as luminescent organometallic gels.