Syntheses and Properties of Dinuclear Group 6 Metal Complexes with the Zwitterionic Sulfur Donor Ligand Bis(N,N-diethylamino)carbenium- dithiocarboxylate
Syntheses and Properties of Dinuclear Group 6 Metal Complexes with the Zwitterionic Sulfur Donor Ligand Bis(N,N-diethylamino)carbenium- dithiocarboxylate
复制标题
两性离子硫供体配体双(N,N-二乙氨基)碳鎓-二硫代羧酸盐双核6族金属配合物的合成及性能
DOI：
10.1021/om300831y
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发表时间：
2013
期刊：
影响因子：
2.8
通讯作者：
and A. Nagasawa
中科院分区：
文献类型：
--
作者：
T. Sugaya;T. Ohba;F. Sai;S. Mashima;T. Fujihara;K. Unoura;and A. Nagasawa
通过[M0（CO）6]与不对称桥联的两性离子硫给体二硫代羧酸二（N，N-二乙基氨基）碳鎓（EtL）在己烷-二氯甲烷中的光化学反应，合成了一类双核第6族金属配合物[{M0（CO）5}2（μ-S，S′-EtL）]（M = Cr，Mo，W）.铬（0）和钨（0）配合物1和3的X射线分析分别揭示了相同的反-反配位模式结构，并从钼（0）配合物2的各种分析数据推测。发现配位模式的相关标准是固态下-CS2部分的不对称伸缩振动波数和溶液中基于配体的还原势。配合物1和3显示出准可逆的还原波，这被归因于来自桥接EtL的两步单电子还原过程。在一系列[Cr（CO）5L]配合物（L =单齿配体）中，反式-L羰基的~（13）C NMR化学位移表明配体的σ-给体/π-受体比值随配体的增大而增大。硫给体配体，包括EtL和EtCl 2，位于该范围的中间。所有配合物均表现出负的溶剂化显色性：随着Reichardt溶剂极性参数ET（30）的增加，最大吸收波长在500-600 nm范围内向蓝侧移动，质子溶剂除外。采用含时密度泛函理论-极化连续模型的量子化学计算方法，研究了配合物3的激发态和溶剂化变色性质。溶液中垂直激发能的计算值与实验值吻合较好，表明该跃迁为金属-配体电荷转移跃迁。此外，UV-vis、NMR和循环伏安法数据表明，配合物3在极性溶剂[W（CO）5（EtL）]和[W（CO）5（溶剂）]中解离成两种单核物种。
A class of dinuclear group 6 metal complexes [{M0(CO)5}2(μ-S,S′-EtL)] (M = Cr, Mo, W) with the asymmetrically bridged zwitterionic sulfur donor bis(N,N-diethylamino)carbeniumdithiocarboxylate (EtL) was prepared by photoreaction of [M0(CO)6] with EtL in hexane–CH2Cl2for Cr and Mo or THF for W. The same structure in asyn–anticoordination mode was revealed by X-ray analyses for chromium(0)andtungsten(0) complexes,1and3, respectively, and speculated from various analytical data for the molybdenum(0) complex2. The pertinent criteria for the coordination mode are found to be the wavenumber of the asymmetric stretching vibration of the −CS2moiety in the solid state and the ligand-based reduction potential in solution. Complexes1and3showed quasi-reversible reduction waves, which are assigned to a two-step, one-electron reduction process derived from the bridging EtL. In a series of [Cr(CO)5L] complexes (L = monodentate ligand), the13C NMR chemical shifts of thetrans-to-L carbonyl group showed the order of increasing σ-donor/π-acceptor ratio of the ligands. The sulfur donor ligands, including EtL and thione, are positioned in the middle of this range. All complexes exhibited negative solvatochromism: the wavelength of the absorption maximum shifted to the blue side in the range 500–600 nm with an increase in the Reichardt solvent polarity parametersET(30), except for protic solvents. Quantum chemical calculations by time-dependent density functional theory–polarized continuum model were employed for understanding the excited states and solvatochromic properties of complex3. The calculated vertical excitation energies in solution are consistent with the experimental data, suggesting that the transition is a metal-to-ligand charge-transfer transition. In addition, UV–vis, NMR, and cyclic voltammetry data showed that complex3dissociates into two mononuclear species in polar solvents: [W(CO)5(EtL)] and [W(CO)5(solvent)].