Structures, fluorescent properties of the Ag(I) compounds based on molecular clips with biphenyl core

Three silver complexes Ag2(L)2(NO3)2 (1), Ag2(L)2(SO3CF3)2(H2O)0.5 (2), and [Ag2(L)2(NO3)2]n (3) were prepared from molecular clips, 2,2′-Bis(imidazol-1-ylmethyl)-biphenyl (L) and structurally characterized to investigate the structural-luminescent relation. Compound 1 is a bimetallic supramolecular rectangle in which two L ligands are connected by two linearly coordinated Ag(I) ions. Compound 2 is described as a double helicate due to the nature of the twist of the imidazole groups after coordination to Ag(I) centers. In compound 3, the Ag(I) centers are connected by L ligands into a one-dimensional zigzag chain. Solid state and solution fluorescent measurements exhibit the presence of ligand-based emission at 415 and 435 nm of compounds 1 and 2, respectively. It is said that the dihedral angles between the two imidazole rings coordinated to one Ag(I) center affect the emission properties.

Graphical abstractThe utilization of different anions and the application of multifarious methods resulted in three silver compounds Ag2(L)2(NO3)2 (1), Ag2(L)2(SO3CF3)2(H2O)0.5 (2), and [Ag2(L)2(NO3)2]n (3) containing different arrangement of molecular clips, 2,2′-Bis(imidazol-1-ylmethyl)-biphenyl (L) and structurally characterized to investigate the structural–luminescence relation. The results revealed that the dihedral angles between the two imidazole rings coordinated to one Ag(I) center is the important factors controlling the emission properties.Figure optionsDownload full-size imageDownload as PowerPoint slide