Probing the Anisotropic Distortion of Photoexcited Spin Crossover Complexes with Picosecond X-ray Absorption Spectroscopy

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• 作者：Sophie E. Canton ; Xiaoyi Zhang ; Lat茅vi M. Lawson Daku ; Amanda L. Smeigh ; Jianxin Zhang ; Yizhu Liu ; Carl-Johan Wallentin ; Klaus Attenkofer ; Guy Jennings ; Charles A. Kurtz ; David Gosztola ; Kenneth W盲rnmark ; Andreas Hauser ; Villy Sundstr枚m
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：February 27, 2014
• 年：2014
• 卷：118
• 期：8
• 页码：4536-4545
• 全文大小：487K
• 年卷期：v.118,no.8(February 27, 2014)
• ISSN：1932-7455

文摘

For numerous spin crossover complexes, the anisotropic distortion of the first coordination shell around the transition metal center governs the dynamics of the high-spin/low-spin interconversion. However, this structural parameter remains elusive for samples that cannot be investigated with crystallography. The present work demonstrates how picosecond X-ray absorption spectroscopy is able to capture this specific deformation in the photoinduced high-spin state of solvated [Fe(terpy)₂]²⁺, a complex which belongs to the prominent family of spin crossover building blocks with nonequivalent metal鈥搇igand bonds. The correlated changes in Fe鈥揘_Axial, Fe鈥揘_Distal, and bite angle N_Distal鈥揊e鈥揘_Axial extracted from the measurements are in very good agreement with those predicted by DFT calculations in D_2d symmetry. The outlined methodology is generally applicable to the characterization of ultrafast nuclear rearrangements around metal centers in photoactive molecular complexes and nanomaterials, including those that do not display long-range order.