DNA-stabilized Ag-Au bimetallic clusters: the effects of alloying and embedding on optical properties.
DNA-stabilized Ag-Au bimetallic clusters: the effects of alloying and embedding on optical properties.
复制标题
DOI：
10.1039/c6cp04352f
复制
发表时间：
2016-07
期刊：
影响因子：
--
通讯作者：
D. Palagin;J. Doye
中科院分区：
文献类型：
--
作者：
D. Palagin;J. Doye
采用全局几何优化和时变密度泛函理论计算，研究了AgnAun （n = 2-6）纳米合金的结构演化和光学性质，包括单个簇和不同大小DNA片段稳定簇。我们表明合金化可以用来控制和调整簇的金属原子和DNA配体的有机片段之间的相互作用水平。例如，金原子和银原子在从核碱基到团簇的电荷转移过程中表现出协同效应，与胞嘧啶的氮原子直接连接的银原子增加了它们的部分正电荷，而它们电负性更强的邻近金原子则携带了多余的负电荷。这使得小双金属簇的几何结构和光学吸收光谱在与相对较大的DNA片段聚集时保留了许多主要特征，例如基于胞嘧啶的9核苷酸发夹环，这表明了这种杂化金属有机化合物的潜在合成途径，并开辟了将双金属纳米合金独特的可调特性带入生物应用的可能性。
Global geometry optimization and time-dependent density functional theory calculations have been used to study the structural evolution and optical properties of AgnAun (n = 2-6) nanoalloys both as individual clusters and as clusters stabilized with the fragments of DNA of different size. We show that alloying can be used to control and tune the level of interaction between the metal atoms of the cluster and the organic fragments of the DNA ligands. For instance, gold and silver atoms are shown to exhibit synergistic effects in the process of charge transfer from the nucleobase to the cluster, with the silver atoms directly connected to the nitrogen atoms of cytosine increasing their positive partial charge, while their more electronegative neighbouring gold atoms host the excess negative charge. This allows the geometrical structures and optical absorption spectra of small bimetallic clusters to retain many of their main features upon aggregation with relatively large DNA fragments, such as a cytosine-based 9-nucleotide hairpin loop, which suggests a potential synthetic route to such hybrid metal-organic compounds, and opens up the possibility of bringing the unique tunable properties of bimetallic nanoalloys to biological applications.