X-ray Emission Spectroscopy To Study Ligand Valence Orbitals in Mn Coordination Complexes

详细信息    查看全文

• 作者：Grigory Smolentsev ; Alexander V. Soldatov ; Johannes Messinger ; Kathrin Merz ; Thomas Weyhermller ; Uwe Bergmann ; Yulia Pushkar ; Junko Yano ; Vittal K. Yachandra ; Pieter Glatzel
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：September 16, 2009
• 年：2009
• 卷：131
• 期：36
• 页码：13161-13167
• 全文大小：304K
• 年卷期：v.131,no.36(September 16, 2009)
• ISSN：1520-5126

文摘

We discuss a spectroscopic method to determine the character of chemical bonding and for the identification of metal ligands in coordination and bioinorganic chemistry. It is based on the analysis of satellite lines in X-ray emission spectra that arise from transitions between valence orbitals and the metal ion 1s level (valence-to-core XES). The spectra, in connection with calculations based on density functional theory (DFT), provide information that is complementary to other spectroscopic techniques, in particular X-ray absorption (XANES and EXAFS). The spectral shape is sensitive to protonation of ligands and allows ligands, which differ only slightly in atomic number (e.g., C, N, O...), to be distinguished. A theoretical discussion of the main spectral features is presented in terms of molecular orbitals for a series of Mn model systems: [Mn(H₂O)₆]²⁺, [Mn(H₂O)₅OH]⁺, and [Mn(H₂O)₅NH₃]²⁺. An application of the method, with comparison between theory and experiment, is presented for the solvated Mn²⁺ ion in water and three Mn coordination complexes, namely [LMn(acac)N₃]BPh₄, [LMn(B₂O₃Ph₂)(ClO₄)], and [LMn(acac)N]BPh₄, where L represents 1,4,7-trimethyl-1,4,7-triazacyclononane, acac stands for the 2,4-pentanedionate anion, and B₂O₃Ph₂ represents the 1,3-diphenyl-1,3-dibora-2-oxapropane-1,3-diolato dianion.