Cyclometalated Platinum(II) Metallomesogens Based on Half-Disc-Shaped β-Diketonate Ligands with Hexacatenar: Crystal Structures, Mesophase Properties, and Semiconductor Devices.

A series of new half-disc-shaped platinum(II) complexes [Pt(ppy)(AL-6OCH)] (, [Pt(ppyF)(AL-6OCH)] (, and [Pt(ppyCF)(AL-6OCH)] ( (AL-6OCH = 1,3-bis(3,4,5-trialkoxyphenyl)propane-1,3-dionato; = 1, 6, 12) with concise structures have been designed and synthesized, in which 2-phenylpyridine (ppy) derivatives were used as cyclometalated ligands and hexacatenar β-diketonate derivatives AL-6OCH as auxiliary ligands. The single-crystal data of the methoxy diketonate analogues , , and indicate that they all display excellent square planarity. These platinum(II) complexes show a certain emission tunability (ranging from λ = 506-535 nm) by the introduction of fluorine or trifluoromethyl into ppy. Thermal studies reveal that the fluorine-substituted complexes are liquid crystals but the trifluoromethyl-substituted complexes are not. The platinum(II) complexes , , and can form a hexagonal columnar mesophase via intermolecular π-π interactions. In addition, compared to the reported platinum(II) metallomesogens, and exhibit improved ambipolar carrier mobility behaviors in semiconductor devices at the liquid crystal states.