Waters Tom, Woo Hin-Koon, Wang Xue-Bin, Wang Lai-Sheng
Department of Physics, Washington State University, Richland, 99354, USA.
J Am Chem Soc. 2006 Apr 5;128(13):4282-91. doi: 10.1021/ja056342s.
A detailed understanding of the electronic structure of transition metal bis(dithiolene) complexes is important because of their interesting redox, magnetic, optical, and conducting properties and their relevance to enzymes containing molybdenum and tungsten bis(dithiolene) centers. The electronic structures of the bis(dithiolene) anions M(mnt)(2) (M = Ni, Pd, Pt; mnt = 1,2-S(2)C(2)(CN)(2); n = 0-2) were examined by a combination of photodetachment photoelectron spectroscopy (PES) and density functional theory calculations. The combined experimental and theoretical data provide insight into the molecular orbital energy levels of M(mnt)(2) and the ground and excited states of M(mnt)(2) and [M(mnt)(2)]. Detachment features from ligand-based orbitals of M(mnt)(2) occur at similar energies for each species, independent of the metal center, while those arising from metal-based orbitals occur at higher energies for the heavier congeners. Electronic excitation energies inferred for M(mnt)(2) from the PES experiments agree well with those obtained in optical absorption experiments in solution, with the PES experiments providing additional insight into the changes in energy of these transitions as a function of metal. The singly charged anions M(mnt)(2) were also prepared and studied independently. Electron detachment from the ground states of these doublet anions accessed the lowest singlet and triplet states of neutral [M(mnt)(2)], thereby providing a direct experimental measure of their singlet-triplet splitting.
深入了解过渡金属双（二硫烯）配合物的电子结构非常重要，因为它们具有有趣的氧化还原、磁性、光学和导电性质，并且与含有钼和钨双（二硫烯）中心的酶相关。通过光解离光电子能谱（PES）和密度泛函理论计算相结合的方法，研究了双（二硫烯）阴离子[M（mnt）₂]ⁿ⁻（M = Ni、Pd、Pt；mnt = 1,2 - S₂C₂(CN)₂；n = 0 - 2）的电子结构。实验和理论数据相结合，为[M（mnt）₂]²⁻的分子轨道能级以及[M（mnt）₂]¹⁻和[M（mnt）₂]的基态和激发态提供了深入了解。对于每个物种，[M（mnt）₂]²⁻基于配体轨道的解离特征出现在相似的能量处，与金属中心无关，而基于金属轨道的解离特征在较重的同系物中出现在更高的能量处。从PES实验推断出的[M（mnt）₂]¹⁻的电子激发能与溶液中光吸收实验获得的结果非常吻合，PES实验还提供了关于这些跃迁能量随金属变化的更多见解。还独立制备并研究了单电荷阴离子[M（mnt）₂]¹⁻。这些二重态阴离子基态的电子脱离进入了中性[M（mnt）₂]的最低单重态和三重态，从而提供了它们单重态 - 三重态分裂的直接实验测量。
