Department of Chemistry, University of South Alabama, Mobile, Alabama 36688, USA.
Inorg Chem. 2012 Mar 19;51(6):3399-408. doi: 10.1021/ic2014495. Epub 2012 Feb 24.
The highly luminescent bimetallic cyanide materials, Gd(terpy)(H(2)O)(NO(3))(2)M(CN)(2) (M = Au, Ag; GdAu and GdAg, respectively) are quick and easy to synthesize under ambient conditions. A characteristic feature exhibited by both solid-state compounds is an intense red emission when excited with UV light. Additionally, GdAu exhibits a broad-band green emission upon excitation in the near UV region. A combination of structural and spectroscopic results for the compounds helps explain the underlying conditions responsible for their unique properties. Single-crystal X-ray diffraction experiments expose their structural features, including the fact that they are isostructural. Crystallographic data for the representative GdAu compound (Mo K(α), λ = 0.71073 Å, T = 290 K): triclinic, space group P ̅1, a = 7.5707(3) Å, b = 10.0671(4) Å, c = 15.1260(4) Å, α = 74.923(3)°, β = 78.151(3)°, γ = 88.401(3)°, V = 1089.04(7) Å(3), and Z = 2. Although the compounds crystallize as dimers containing M···M distances smaller than the sum of their van der Waals radii, the Au···Au (3.5054(4) Å) and/or the Ag···Ag (3.6553(5) Å) interactions are relatively weak and are not responsible for the low energy red emission. Rather, the green emission in GdAu presumably originates from the Au(CN)(2)(-) dimeric excimer, while the Ag(CN)(2)(-) dimers in GdAg do not display visible emission at either 290 or 77 K. The unusual red emission exhibited by both compounds likely originates from the formation of an excited state exciplex that involves intermolecular π-stacking of 2,2':6',2"-terpyridine ligands. The room-temperature and low-temperature steady-state photoluminescent properties, along with detailed time-dependent, lifetime, and quantum yield spectroscopic data provide evidence regarding the sources of the multiple visible emissions exhibited by these complexes.
高发光的双金属氰化物材料 Gd(terpy)(H(2)O)(NO(3))(2)M(CN)(2)（M = Au、Ag；GdAu 和 GdAg，分别）在环境条件下易于快速合成。两种固态化合物的一个特征是在紫外光激发下发出强烈的红色发射。此外，GdAu 在近紫外区域激发时显示出宽频带绿光发射。化合物的结构和光谱结果的组合有助于解释导致其独特性质的基本条件。化合物的单晶 X 射线衍射实验揭示了它们的结构特征，包括它们是同构的事实。代表性 GdAu 化合物的晶体学数据（Mo K(α)，λ = 0.71073 Å，T = 290 K）：三斜晶系，空间群 P ̅1，a = 7.5707(3) Å，b = 10.0671(4) Å，c = 15.1260(4) Å，α = 74.923(3)°，β = 78.151(3)°，γ = 88.401(3)°，V = 1089.04(7) Å(3)，Z = 2。尽管这些化合物结晶为含有 M···M 距离小于其范德华半径之和的二聚体，但 Au···Au（3.5054(4) Å）和/或 Ag···Ag（3.6553(5) Å）相互作用相对较弱，并不是导致低能红色发射的原因。相反，GdAu 中的绿色发射可能源自Au(CN)(2)(-)二聚体激基复合物，而 GdAg 中的Ag(CN)(2)(-)二聚体在 290 K 或 77 K 时均不显示可见发射。两种化合物所表现出的不寻常的红色发射可能源自形成激发态激基复合物的过程，该过程涉及 2,2':6',2"-三联吡啶配体的分子间π堆积。室温及低温稳态光致发光特性以及详细的时间依赖性、寿命和量子产率光谱数据为这些配合物所表现出的多种可见发射的来源提供了证据。
