Single-ligand exchange on an Au-Cu bimetal nanocluster and mechanism
Single-ligand exchange on an Au-Cu bimetal nanocluster and mechanism
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Au-Cu双金属纳米团簇上的单配体交换及其机制
DOI：
10.1039/c8nr01611a
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发表时间：
2018
期刊：
影响因子：
6.7
通讯作者：
Jin Rongchao
中科院分区：
文献类型：
--
作者：
Song Yongbo;Lv Ying;Zhou Meng;Luo Tian-Yi;Zhao Shuo;Rosi Nathaniel L.;Yu Haizhu;Zhu Manzhou;Jin Rongchao
得到了一个由硒化物和磷化氢共同包覆的Au-Cu纳米簇，其X-射线结构表明其为一个二十面体的Au 13核，由三个CuSe 2 PPh 2 Py基序和一个CuSe 3基序包围，分子式为[Au 13 Cu 4（PPh 2 Py）3（SePh）9]。有趣的是，在生长反应中观察到单配体交换过程，其中首先形成[Au 13 Cu 4（PPh 2 Py）4（SePh）8]+中间体，但是延长的反应导致一个PPh 2 Py配体被PhSe配体选择性地取代。DFT模拟结果表明，空间位阻和键离解能对单配体交换反应以及热力学都有很大的影响，这有助于理解配体交换反应的机理. Au-Cu纳米团簇的紫外-可见吸收和光致发光（PL）的温度依赖性表明，其光学性质主要是由金属核贡献的。飞秒时间分辨泵浦探测分析绘制出PL过程的进一步细节。
An Au–Cu bimetallic nanocluster co-capped by selenolate and phosphine is obtained and its X-ray structure shows an icosahedral Au13 kernel surrounded by three CuSe2PPh2Py motifs and one CuSe3 motif, formulated as [Au13Cu4(PPh2Py)3(SePh)9]. Interestingly, a single-ligand exchange process is observed in the growth reaction, in which an [Au13Cu4(PPh2Py)4(SePh)8]+ intermediate is first formed, but a prolonged reaction leads to one PPh2Py ligand being selectively replaced by a PhSe-ligand. DFT simulations reveal that both steric hindrance and bond dissociation energy have great effects on the single-ligand exchange reaction as well as the thermodynamics, which help to understand the mechanism of the ligand exchange. Temperature-dependent UV-vis absorption and photoluminescence (PL) properties of the Au–Cu nanocluster imply that the optical properties are mainly contributed by the metal core. Femtosecond time-resolved pump–probe analysis maps out further details of the PL process.