Chatterjee Tanmay, Mandal Mrinal, Das Ananya, Bhattacharyya Kalishankar, Datta Ayan, Mandal Prasun K
Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur, West-Bengal 741246, India.
Department of Spectroscopy, Indian Association for the Cultivation of Science , 2A and 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India.
J Phys Chem B. 2016 Apr 14;120(14):3503-10. doi: 10.1021/acs.jpcb.6b01993. Epub 2016 Mar 31.
Dual fluorescence of GFP chromophore analogues has been observed for the first time. OHIM (o-hydroxy imidazolidinone) shows only a charge transfer (CT) band, CHBDI (p-cyclicamino o-hydroxy benzimidazolidinone) shows a comparable intensity CT and PT (proton transfer) band, and MHBDI (p-methoxy o-hydroxy benzimidazolidinone) shows a higher intensity PT band. It could be shown that the differential optical behavior is not due to conformational variation in the solid or solution phase. Rather, control of the excited state electronic energy level and excited state acidity constant by functional group modification could be shown to be responsible for the differential optical behavior. Chemical modification-induced electronic control over the relative intensity of the charge transfer and proton transfer bands could thus be evidenced. Support from single-crystal X-ray structure, NMR, femtosecond to nanosecond fluorescence decay analysis, and TDDFT-based calculation provided important information and thus helped us understand the photophysics better.
首次观察到绿色荧光蛋白发色团类似物的双荧光现象。邻羟基咪唑烷酮（OHIM）仅显示电荷转移（CT）带，对环氨基邻羟基苯并咪唑烷酮（CHBDI）显示强度相当的CT带和质子转移（PT）带，而对甲氧基邻羟基苯并咪唑烷酮（MHBDI）显示强度更高的PT带。结果表明，这种不同的光学行为并非源于固相或溶液相中的构象变化。相反，通过官能团修饰对激发态电子能级和激发态酸度常数的控制被证明是造成这种不同光学行为的原因。因此，可以证明化学修饰引起的电子控制对电荷转移带和质子转移带的相对强度产生了影响。单晶X射线结构、核磁共振、飞秒到纳秒荧光衰减分析以及基于含时密度泛函理论（TDDFT）的计算提供的支持给出了重要信息，从而帮助我们更好地理解光物理过程。
