Fluorescence in Rhoda- and Iridacyclopentadienes Neglecting the Spin–Orbit Coupling of the Heavy Atom: The Ligand Dominates
作者:Andreas Steffen、Karine Costuas、Abdou Boucekkine、Marie-Hélène Thibault、Andrew Beeby、Andrei S. Batsanov、Azzam Charaf-Eddin、Denis Jacquemin、Jean-François Halet、Todd B. Marder
DOI:10.1021/ic501115k
日期:2014.7.7
We present a detailed photophysical study and theoretical analysis of 2,5-bis(arylethynyl)rhodacyclopenta-2,4-dienes (1a–c and 2a–c) and a 2,5-bis(arylethynyl)iridacyclopenta-2,4-diene (3). Despite the presence of heavy atoms, these systems display unusually intense fluorescence from the S1 excited state and no phosphorescence from T1. The S1 → T1 intersystem crossing (ISC) is remarkably slow with
我们提出了详细的光物理研究和理论分析的2,5-双(芳基乙炔基)rhodacyclopenta-2,4-二烯(1a – c和2a – c)和2,5-双(芳基乙炔基)iridacyclopenta-2,4-二烯(3)。尽管存在重原子,但这些系统仍显示出异常强烈的S 1激发态荧光,而T 1没有磷光。S 1 →T 1系统间穿越(ISC)非常慢,速率常数为10 8 s –1(即,以纳秒为单位)。传统上,对于带有4d或5d金属的有机金属系统,ISC的速度要快2-3个数量级。发光寿命的测量表明,标题化合物经历小号1 →T的1个互主要通过上述233 K.相关的实验活化能热活化ISC信道被发现为Δ ħ ISC ⧧ = 28千焦耳摩尔-1(2340厘米-1)为1A,这是由密度泛函理论(DFT)和时间依赖性的DFT计算[Δ支持ħ ISC ⧧(计算值)= 11千焦耳摩尔-1(920厘米-1)为1A-H]。然而,在233