X-ray absorption spectroscopic and theoretical studies on (L)2[Cu2(S2)n]2+ complexes: disulfide versus disulfide(*1-) bonding.
X-ray absorption spectroscopic and theoretical studies on (L)2[Cu2(S2)n]2+ complexes: disulfide versus disulfide(*1-) bonding.
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(L)2[Cu2(S2)n]2 配合物的 X 射线吸收光谱和理论研究：二硫键与二硫键 (*1-) 键合。
DOI：
10.1021/ja0762745
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发表时间：
2008
影响因子：
15
通讯作者：
Solomon,EdwardI
中科院分区：
文献类型：
--
作者：
Sarangi,Ritimukta;York,JohnT;Helton,MatthewE;Fujisawa,Kiyoshi;Karlin,KennethD;Tolman,WilliamB;Hodgson,KeithO;Hedman,Britt;Solomon,EdwardI
利用密度泛函理论（DFT）结合X射线吸收光谱（XAS）数据对[{（TMPA）Cu} 2S 2]（ClO 4）2（1），[{Cu[HB（3，5-Pri 2 pz）3]}2（S2）]（2）和[{（TMEDA）Cu}2（S2）2]（OTf）2（3）进行了计算，得到了它们基态波函数的定量描述. Cu的L边强度在基态1和2中分别给出63%和37%的Cu d-特征，而S的K边前强度在基态分别给出20%和48%的S特征。这些数据表明2中总的二硫键特征比1增加了2倍以上。与1（（μ −η1：η 1 S22-bridge）相比，2（μ−η2：η 2S 22-bridge）中Cu−S键数量的增加主要决定了2中共价和Cu-二硫键强度的大幅增加。Cu K-和L-和S K-前边缘能量位置直接证明了3的Cu II/（S2-）2性质。3中的两个二硫键（·1−）经历强的成键相互作用，使相对于Cu 3d能级的（S2-）2片段的填充反键π* 轨道不稳定。这导致了在3中的反向键合方案，其基态主要是基于配体的空穴，与其作为二铜（II）-双二硫化物（·1−）络合物的描述一致。
Cu K-, Cu L-, and S K-edge X-ray absorption spectroscopic (XAS) data have been combined with density functional theory (DFT) calculations on [{(TMPA)Cu}2S2](ClO4)2(1), [{Cu[HB(3,5-Pri2pz)3]}2(S2)] (2), and [{(TMEDA)Cu}2(S2)2](OTf)2(3) to obtain a quantitative description of their ground state wavefunctions. The Cu L-edge intensities give 63 and 37% Cu d-character in the ground state of1and2, respectively, whereas the S K-pre-edge intensities reflect 20 and 48% S character in their ground states, respetively. These data indicate a more than 2-fold increase in the total disulfide bonding character in2relative to1. The increase in the number of Cu−S bonds in2(μ−η2:η2S22-bridge) compared to1((μ−η1:η1S22-bridge) dominantly determines the large increase in covalency and Cu-disulfide bond strength in2. Cu K- and L- and S K-pre-edge energy positions directly demonstrate the CuII/(S2-)2nature of3. The two disulfide(•1−)'s in3undergo strong bonding interactions that destabilize the resultant filled antibonding π* orbitals of the (S2-)2fragment relative to the Cu 3d levels. This leads to an inverted bonding scheme in3with dominantly ligand-based holes in its ground state, consistent with its description as a dicopper(II)-bis-disulfide(•1−) complex.