硒(二硫代)双(烯-1,2-二硫醇ate)钼(IV)配合物（硫族元素 E = O，S，Se）：探究 Mo≡E 和烯-1,2-二硫醇ate 取代基对几何和电子结构的影响。
Chalcogenidobis(ene-1,2-dithiolate)molybdenum(IV) complexes (chalcogenide E = O, S, Se): probing Mo≡E and ene-1,2-dithiolate substituent effects on geometric and electronic structure.
机构信息
Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
出版信息
Dalton Trans. 2011 Feb 7;40(5):1119-31. doi: 10.1039/c0dt00871k. Epub 2010 Dec 16.
New square-pyramidal bis(ene-1,2-dithiolate)MoSe complexes, Mo(IV)Se(L)(2), have been synthesised along with their terminal sulfido analogues, Mo(IV)S(L)(2), using alkyl (L(C(4)H(8))), phenyl (L(Ph)) and methyl carboxylate (L(COOMe)) substituted dithiolene ligands (L). These complexes now complete three sets of Mo(IV)O, Mo(IV)S and Mo(IV)Se species that are coordinated with identical ene-1,2-dithiolate ligands. The alkyl substituted Mo(S/Se)(L(C(4)H(8)))(2) complexes were reported in prior investigations (H. Sugimoto, T. Sakurai, H. Miyake, K. Tanaka and H. Tsukube, Inorg. Chem. 2005, 44, 6927, H. Tano, R. Tajima, H. Miyake, S. Itoh and H. Sugimoto, Inorg. Chem. 2008, 47, 7465). The new series of complexes enable a systematic investigation of terminal chalcogenido and supporting ene-1,2-dithiolate ligand effects on geometric structure, electronic structure, and spectroscopic properties. X-ray crystallographic analysis of these (Et(4)N)(2)[MoEL(2)] (E = terminal chalocogenide) complexes reveals an isostructural Mo centre that adopts a distorted square pyramidal geometry. The M≡E bond distances observed in the crystal structures and the ν(M≡E) vibrational frequencies indicate that these bonds are weakened with an increase in L→Mo electron donation (L(COOMe) < L(Ph) < L(C(4)H(8))), and this order is confirmed by an electrochemical study of the complexes. The (77)Se NMR resonances in MoSeL complexes appear at lower magnetic fields as the selenido ion became less basic from MoSeL(C(4)H(8)), MoSeL(Ph) and MoSeL(COOMe). Electronic absorption and resonance Raman spectroscopies have been used to assign key ligand-field, MLCT, LMCT and intraligand CT bands in complexes that possess the L(COOMe) ligand. The presence of low-energy intraligand CT transition in these MoEL(COOMe) compounds directly probes the electron withdrawing nature of the -COOMe substituents, and this underscores the complex electronic structure of square pyramidal bis(ene-1,2-dithiolate)-Mo(IV) complexes that possess extended dithiolene conjugation.
新的四方锥型双(烯-1,2-二硫醇)MoSe 配合物，[Mo(IV)Se(L)(2)]2-，以及它们的端基硫化物类似物，[Mo(IV)S(L)(2)]2-，使用烷基（L(C4H8))、苯基（L(Ph)) 和甲基羧酸盐（L(COOMe))取代的二硫醇配体（L)合成。这些配合物现在完成了三套 Mo(IV)O、Mo(IV)S 和 Mo(IV)Se 物种，它们与相同的烯-1,2-二硫醇配体配位。[烷基取代的 Mo(S/Se)(L(C4H8))(2)]2-配合物在先前的研究中已经报道过（H. Sugimoto, T. Sakurai, H. Miyake, K. Tanaka 和 H. Tsukube, Inorg. Chem. 2005, 44, 6927, H. Tano, R. Tajima, H. Miyake, S. Itoh 和 H. Sugimoto, Inorg. Chem. 2008, 47, 7465)。新的配合物系列使我们能够系统地研究端基硫属元素和支持的烯-1,2-二硫醇配体对几何结构、电子结构和光谱性质的影响。这些（Et(4)N)(2)[MoEL(2)]（E = 端基硫属元素）配合物的 X 射线晶体结构分析揭示了一个具有扭曲的四方锥型几何结构的等结构 Mo 中心。在晶体结构中观察到的 M≡E 键距离和 ν(M≡E)振动频率表明，这些键随着 L→Mo 电子供体的增加而减弱（L(COOMe) < L(Ph) < L(C4H8))，这一顺序通过对配合物的电化学研究得到了证实。MoSeL 配合物中的(77)Se NMR 共振出现在较低的磁场中，因为硒离子从 MoSeL(C4H8))、MoSeL(Ph) 和 MoSeL(COOMe)变得不那么碱性。电子吸收和共振拉曼光谱已被用于确定具有 L(COOMe)配体的配合物中的关键配体场、MLCT、LMCT 和内配体 CT 带。这些 MoEL(COOMe)化合物中存在低能量的内配体 CT 跃迁直接探测到 -COOMe 取代基的吸电子性质，这突出了具有扩展二硫烯共轭的四方锥型双(烯-1,2-二硫醇)-Mo(IV)配合物的复杂电子结构。
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