Departamento de Ciencias Quimicas, Universidad Andres Bello, Republica 275, Santiago, Chile.
J Phys Chem A. 2012 Jan 12;116(1):520-5. doi: 10.1021/jp2071277. Epub 2011 Dec 29.
Insights into the ground and excited states involved in the reported luminescent behavior of a complex involving the Ag(3) core stabilized by pyridil derivatives of N-heterocyclic carbenes has been achieved by means relativistic DFT calculations including scalar and spin-orbit coupling. The stabilization of the Ag(3) core is enhanced by the population of a highly symmetric bonding Ag(3) orbital, composed of 75% from the 5s, 15% from 5p, and 10% from 4d. Thus, stabilization of the Ag(3) core involves a slightly bonded d(10) metallic core in addition to the pure nonbonding argentophilic interaction picture. It is suggested that the population of this highly bonding Ag(3) orbital is responsible of the short Ag-Ag bond length observed in the studied compounds. The characterized electronic excitations allows to rule that the metal-ligand to ligand charge-transfer transitions account for the luminescent properties. The calculated Stokes shifts are in good agreement with the experimental data.
通过相对论密度泛函理论（DFT）计算，包括标量和自旋轨道耦合，对涉及由吡啶基取代的 N-杂环卡宾稳定的 Ag(3)核心的配合物的发光行为所涉及的基态和激发态进行了深入研究。通过 5s、15%的 5p 和 10%的 4d 轨道组成的高度对称的键合 Ag(3)轨道的电子填充，增强了[Ag(3)]3+核心的稳定性。因此，Ag(3)核心的稳定化涉及到一个略微键合的 d(10)金属核心，除了纯非键合的银相互作用图像之外。有人认为，这种高度键合的[Ag(3)]3+轨道的电子填充是导致所研究化合物中观察到的短 Ag-Ag 键长的原因。所确定的电子激发允许排除金属-配体到配体电荷转移跃迁对发光性质的贡献。计算的斯托克斯位移与实验数据吻合良好。
