Synthesis,Structure and Photophysical Properties of a Dinuclear Copper (Ⅰ) Complex Based on Phosphinopyridine and Diphosphine Mixed-ligands

Treatment of bis(diphenylphosphino)methane(dppm)and 2-(diphenylphosphanyl)pyridine(dpppy)with Cu(CH₃CN)₄BF₄afforded a dinuclear Cu(I)complexCu₂(dpppy)₂(dppm)(CH₃CN)](BF₄)₂·3CH₂Cl₂(1).Complex 1 was structurally characterized by X-ray single-crystal analysis and its photophysical properties were studied in detail.It crystallizes in triclinic space group P1^-with a=13.0834(8),b=13.5568(8),c=21.8544(11)?,α=76.090(5)°,β=80.803(5)°,γ=64.582(6)°,V=3391.3(3)?³,Z=2,M_r=1507.42,D_c=1.476 g/cm³,F(000)=1532,GOOF=1.071,the final R=0.0700 for 9041 observed reflections with I>2σ(I)and wR=0.2063 for all data.The complex contains a Cu₂-core structure surrounded by one dppm and two dpppy ligands in a head-to-head arrangement.In the crystalline phase,complex 1 exhibits bright bluish-green photoluminescence(λ_max=488 nm)with high quantum yield(?=0.57)at room temperature.It is still a relatively high emission quantum yield(?=0.36)in doped PMMA thin film with 20 wt%dopant of complex 1.The emission peaks of 1 in dichloromethane solution and doped PMMA(20 wt%)thin films are 510 and 494 nm,respectively,showing a very slight bathochromic shift compared to that in crystalline phase.This phenomenon might be attributed to its rigid conformation that precludes the possible distortion of copper centers in the excited state.