Gawelda Wojciech, Johnson Melanie, de Groot Frank M F, Abela Rafael, Bressler Christian, Chergui Majed
Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Institut des Sciences et Ingénierie Chimiques, CH-1015 Lausanne-Dorigny, Switzerland.
J Am Chem Soc. 2006 Apr 19;128(15):5001-9. doi: 10.1021/ja054932k.
L(2,3) X-ray absorption spectra of aqueous [Ru(II)(bpy)3]2+ have been recorded in its ground and excited states, 50 ps after short pulse laser excitation. Significant changes in both the XANES (X-ray Near-Edge Absorption Structure) and the EXAFS (Extended X-ray Absorption Fine Structure) regions of the excited state complex are detected. The XANES line shapes have been quantitatively simulated using a crystal field multiplet code in trigonal symmetry. In addition, spectral changes in the EXAFS region of both ground and excited states are analyzed in order to extract structural parameters of their corresponding molecular structures. We obtain a Ru-N bond contraction by approximately 0.03 angstroms in the excited-state complex, as compared to the ground-state compound. This contraction results from electrostatic and polarization contributions, limited by steric constraints on the bpy ligands.
已记录了水相中[Ru(II)(bpy)₃]²⁺在基态和短脉冲激光激发50皮秒后的激发态下的L(2,3) X射线吸收光谱。检测到激发态配合物的XANES（X射线近边吸收结构）和EXAFS（扩展X射线吸收精细结构）区域都有显著变化。利用三角对称的晶体场多重态代码对XANES线形进行了定量模拟。此外，还分析了基态和激发态的EXAFS区域的光谱变化，以提取其相应分子结构的结构参数。与基态化合物相比，我们发现在激发态配合物中Ru-N键收缩了约0.03埃。这种收缩是由静电和极化作用引起的，受bpy配体的空间位阻限制。
