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)complex[Cu₂(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.     

“样例-探究”在补救教学中的实践初探

作为一名一线的数学教师，避免不了会与“数学学困生”打交道，这些学生在数学学习上一些数学基本技能、计算的技巧和解题的策略与其他学生相比相对落后，数学知识结构“断网破链”，怎样提高这些学生的成绩，是笔者一直思考和研究的一个问题．在查阅大量的理论资料的基础上，结合实践的经验，笔者在对这些学生进行补救教学的过程中尝试使用“样例一探究”的补救教学模式．