A new luminescent platinum(II) chloride complex of 6-(5-trifluoromethyl-1,2,4-triazol-3-yl)-4,4′-dimethyl-2,2′-bipyridine

A new Pt(II) chloride complex Pt(ftmbpy)Cl (1) with deprotonated 6-(5-trifluoromethyl-1,2,4-triazol-3-yl)-4,4′-dimethyl-2,2′-bipyridine terdentate ligand has been synthesized and characterized. Complex 1 gives a distorted square-planar configuration with a mono-anionic chelate ftmbpy, and displays a 1-D zigzag head-to-tail arrangement along the b axis formed via intermolecular π⋯π stacking and Pt⋯Pt interactions. A relatively weak broad absorption is observed at 360–435 nm in dilute CH2Cl2 solution at room temperature, tentatively ascribed to metal-to-ligand charge transfer (1MLCT) excited state with some mixing of intra-ligand 1ππ* character inside ftmbpy, as supported by TD-DFT analysis. It is demonstrated that complex 1 is emissive in both solution and solid states and exhibits the concentration-dependent luminescence properties originating from intermolecular Pt⋯Pt and π⋯π interactions, and the introduction of substituents (e.g. two methyl groups) into the 2,2′-bipyridyl ring is effective for improving the solubility of Pt(II) complexes.