L-edge spectroscopy of molybdenum compounds and enzymes
L-edge spectroscopy of molybdenum compounds and enzymes
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钼化合物和酶的 L 边光谱
DOI：
10.1021/ja00163a010
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发表时间：
1990
影响因子：
15
通讯作者：
S. Cramer
中科院分区：
文献类型：
--
作者：
G. George;W. Cleland;J. Enemark;B. E. Smith;C. Kipke;S. Roberts;S. Cramer
钼 L{sub 2} 和 L{sub 3} 边缘的光谱已通过使用同步加速器辐射记录并根据配体场理论进行了分析。在氯氧化钼络合物的导数光谱中观察到四个不同的 p {yields} d 跃迁。与相同化合物以及 Tc 类似物的光学数据进行比较表明，L{sub 2,3} 边缘光谱定性地反映了未填充的 Mo d 能级分裂。半经验相关方案使用 Racah 参数来校正交换和库仑相互作用，预测光学分裂的准确度优于 5%。此功能用于拒绝 MoO{sub 4}{sup 2{minus}}、MoOCl{sub 4}(H{sub 2}O){sup {minus}} 和 MoOCl{sub 5}{sup {minus}} 光谱的某些解释。 (N(Et){sub 4})(MoOCl{sub 4}(H{sub 2}O)) 的单晶光谱有助于确认分配。研究了 LMoOXY 化合物对 Mo L 边光谱的化学影响，其中 L 代表氢三(3,5-二甲基-1-吡唑基)硼酸盐，X 和 Y 是各种配体。还比较了对氧化态、末端氧代与末端硫基配体以及不同卤离子的光谱敏感性。
Spectra at the molybdenum L{sub 2} and L{sub 3} edges have been recorded by use of synchrotron radiation and analyzed in terms of ligand field theory. Four distinct p {yields} d transitions were observed in the derivative spectra of molybdenum oxychloride complexes. Comparison with optical data for the same compounds, as well as for Tc analogues, showed that L{sub 2,3}-edge spectra qualitatively reflect the unfilled Mo d-level splittings. A semiempirical correlation scheme, using Racah parameters to correct for exchange and Coulomb interactions, predicted optical splittings with an accuracy of better than 5%. This capability was used to reject certain interpretations of the MoO{sub 4}{sup 2{minus}}, MoOCl{sub 4}(H{sub 2}O){sup {minus}}, and MoOCl{sub 5}{sup {minus}} spectra. Single-crystal spectra for (N(Et){sub 4})(MoOCl{sub 4}(H{sub 2}O)) helped confirm the assignments. Chemical effects on Mo L-edge spectra were surveyed for LMoOXY compounds, where L represents hydrotris(3,5-dimethyl-1-pyrazolyl)borate and X and Y are various ligands. Spectral sensitivity to oxidation state, terminal oxo vs terminal sulfido ligands, and different halide ions are also compared.