Metal-Cation-Directed Assembly of Two M–I (M = Cu, Ag) Clusters: Structures, Thermal Behaviors, Theoretical Studies, and Luminescence Properties

Two new M–I (M = Cu, Ag) clusters, {[Ce(DMF)8][Cu8I11]·C2H5OH}n (1) (DMF = dimethylfomamide) and {[Co(DMF)6]4[Ag7I11]2} (2), were synthesized with the direction of solvent-associated metal cations ([Ce(DMF)8]3+ in 1 and [Co(DMF)6]2+ for 2). Clusters 1 and 2 have been well-characterized by elemental analysis, infrared spectroscopy, ultraviolet/visible spectroscopies, single-crystal X-ray diffraction and thermogravimetric analysis. 1 contains the eight-coordinated cations [Ce(DMF)8]3+ and 1D polymeric anionic chain {[Cu8I11]3−}n, which is constructed from [Cu8I11]3− clusters connected with each other through µ3-I bridges and exhibits an interesting wavy chain structure. Cluster 2 consists of the six-coordinated cations [Co(DMF)6]2+ and the dimeric anionic cluster {[Ag7I11]2}8−, which is fabricated by a pair of heptanuclear butterfly-like clusters connected by two Ag–I bridges. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations at the B3LYP/LanL2DZ*+6-31G* level were performed on clusters 1 and 2 to rationalize their experimental absorption spectra. Solid-state luminescence properties of clusters 1 and 2 have also been investigated at room temperature.