Luminescent Anionic Cyclometalated Organoplatinum (II) Complexes with Terminal and Bridging Cyanide Ligand: Structural and Photophysical Properties

[Image: see text] We present the synthesis and characterization of two series of mononuclear heteroleptic anionic cycloplatinated(II) complexes featuring terminal cyanide ligand Q(+)[Pt(C^N)(p-MeC(6)H(4))(CN)](−) [C^N = benzoquinolate (bzq), Q(+) = K(+)1 and NBu(4)(+)4; 2-phenylpyridinate (ppy), Q(+) = K(+)2 and NBu(4)(+)5 and 2-(2,4- difluorophenyl)pyridinate (dfppy), Q(+) = K(+)3 and NBu(4)(+)6] and a series of symmetrical binuclear complexes (NBu(4))[Pt(2)(C^N)(2)(p-MeC(6)H(4))(2)(μ-CN)] (C^N = bzq 7, ppy 8, dfppy 9). Compounds 5, 6, and 7–9 were further determined by single-crystal X-ray diffraction. There are no apparent intermolecular Pt···Pt interactions owing to the presence of bulky NBu(4)(+) counterion. Slow crystallization of K[Pt(ppy)(p-MeC(6)H(4))(CN)] 2 in acetone/hexane evolves with formation of yellow crystals, which were identified by single-crystal X-ray diffraction methods as the salt complex {[Pt(ppy)(p-MeC(6)H(4))(CN)](2)K(3)(OCMe(2))(4)(μ-OCMe(2))(2)}[Pt(ppy)(p-MeC(6)H(4))(μ-CN)Pt(ppy)(p-MeC(6)H(4))]·2acetone (10), featuring the binuclear anionic unit 8(–) neutralized by an hybrid inorganic–organometallic coordination polymer {[Pt(ppy)(p-MeC(6)H(4))(CN)](2)K(3)(OCMe(2))(4)(μ-OCMe(2))(2)}(+). The photophysical properties of all compounds were recorded in powder, polystyrene film, and solution states with a quantum yield up to 21% for 9 in the solid state. All complexes displayed bright emission in rigid media, and for the interpretation of their absorption and emission properties, density functional theory (DFT) and time-dependent DFT calculations were applied.