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

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.