Synthesis, Structures, and Properties of Polynuclear Silver(I) Complexes Containing Tetra-Phosphine Ligand with Ag⋅⋅⋅C Interactions

Abstract

Reaction of AgNO3 and N,N,N′,N′-tetrakis((diphenylphosphino)methyl)benzene-1,4-diamine (pbaa) with sodium N-ethyldithiocarbamate (Na(Etdtc)) in CH3CN/toluene and CH3CN/DMF solvents produced two Ag4S4-based coordination complexes [Ag4(pbaa)(µ-κ1S,κ2S-Etdtc)4] (1) and [Ag4(pbaa)(µ-κ1S,κ2S-Etdtc)2(µ-κ1S,κ1S-Etdtc)2] (2). Structural analysis shows that the Ag4S4 cores in 1 are interconnected by one pbaa ligand in a tetradentate mode and four Etdtc– anions in a µ-κ1S,κ2S mode to form a three-layer conformation, whereas the Ag4S4 cores in 2 are linked by ligands pbaa (the tetradentate mode) and Etdtc– (the µ-κ1S,κ1S and µ-κ1S,κ2S modes) to yield the other type of three-layer conformation. In addition, in different solvent systems, the Ag atoms also form different types of weak Ag···C interactions with Ag···C distances of 3.297–3.344 Å in 1 and 3.237–3.416 Å in 2. The emission spectrum of complex 1 in DMF solution displays a broad orange–red emission peak at 518 nm, which may be assigned to the ligand-to-metal charge transfer transition.