Monometallic and Bimetallic Platinum Complexes with Fluorinated β‑Diketiminate Ligands

Presented here are complexes of two different fluorinated β-diketiminate (NacNac) ligands with cyclometalated platinum. Reaction of the cyclometalated platinum dimers [Pt­(C^N)­(μ-X)]2 [C^N = 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)­pyridine (F2ppy); X = Cl, Br] with lithium salts of backbone-fluorinated β-diketiminate ligands produces two structure types, depending on the temperature of the reaction. At milder temperatures (100 °C), the major species is a monoplatinum complex of the type Pt­(C^N)­(NacNac). The complexes display reduction waves in their cyclic voltammograms at mild potentials, as well as intense visible absorption bands (λ > 500 nm), that depend minimally on the identity of the C^N ligand or, in the case of the bimetallic complexes, the identity of the bridging halide. In addition, the monoplatinum complexes exhibit structured luminescence in the red and near-infrared regions deriving a NacNac-centered triplet state. All of these observations suggest that the NacNac π system contributes substantially to the frontier orbitals and motivates continued exploration of fluorinated β-diketiminate ligands in the design of complexes with desirable ligand-based redox and optical properties.