Adeagbo Adebola, Wei Tao, Clayborne Andre Z
Department of Chemistry, Howard University, Washington, District of Columbia 20059, United States.
Department of Chemical Engineering, Howard University, Washington, District of Columbia 20059, United States.
J Phys Chem A. 2020 Aug 13;124(32):6504-6510. doi: 10.1021/acs.jpca.0c03992. Epub 2020 Aug 4.
Atomically precise copper clusters (APC) have attracted attention for their promise in sensing, water remediation, and electrochemical technologies. However, smaller-sized APCs and the evolution of their properties as a function of size and composition are not clearly understood. Here, we have performed an investigation into the electronic structure, geometry, and optical properties of small atomically precise copper clusters using density functional theory (DFT) and time-dependent DFT. Through comparative analysis, we show that the electronic structures of the experimentally characterized clusters, Cu(PN(CH)CH) and Cu(SNCH), are similar with the closed-shell superatom character 1S1P. By changing the ligand on Cu(PN(CH)CH) and Cu(SNCH), there were no major changes observed in the tetrahedral Cu core geometry, electronic structure, or optical spectra. However, a change in the anchor atom causes an increase in the electronic gap and induces a hypochromic shift in the onset peak in the optical spectrum of the small clusters. Increasing the copper core size showed small changes Cu-Cu bond lengths, lower electronic gap values, and a bathochromic shift in the optical spectra. Computational results not only provide detailed physical insight into APCs but also aid in identifying compound compositions of small atomically precise nanoclusters from data collected in the experiment.
原子精确铜簇（APC）因其在传感、水修复和电化学技术方面的潜力而备受关注。然而，尺寸较小的APC及其性质随尺寸和组成的变化尚不清楚。在此，我们利用密度泛函理论（DFT）和含时DFT对小尺寸原子精确铜簇的电子结构、几何结构和光学性质进行了研究。通过对比分析，我们表明实验表征的簇Cu(PN(CH)CH)和Cu(SNCH)的电子结构与闭壳层超原子特征1S1P相似。通过改变Cu(PN(CH)CH)和Cu(SNCH)上的配体，在四面体铜核几何结构、电子结构或光谱中未观察到重大变化。然而，锚定原子的变化会导致电子能隙增加，并在小簇的光谱起始峰中引起减色位移。增加铜核尺寸显示出Cu-Cu键长的微小变化、较低的电子能隙值以及光谱中的红移。计算结果不仅为APC提供了详细的物理见解，还有助于从实验收集的数据中识别小尺寸原子精确纳米簇的化合物组成。
