Binuclear luminescent silver(I) – N-heterocyclic carbene complex derived from 1-picolyl-3-pyrimidylbenzimidazoliumhexaflurophosphate

• NCN pincer NHC ligand.
• Ag2 cluster stabilized by NHC.
• d10–d10 ‘argentophilic’ interaction and luminescence.

Starting from the novel proligand 1-picolyl-3-pyrimidylbenzimidazoliumhexaflurophosphate (1), the binuclear silver (I) complex (2) has been synthesized and both the compounds (1–2) have been characterized by different spectroscopic techniques. Finally, the solid state structure of 2 has been determined by single crystal X-ray diffraction studies. The role of non-covalent π–π stacking interactions in stabilizing the self-assembly process appears to be of great importance in the title complex. Additional weak forces like C–H⋯π and anion⋯π interactions are also found to be operating in 2. A rare combination of these interactions in 2, of the type C–H⋯π/π⋯π/π⋯H–C and anion⋯π/π⋯π/π⋯anion, is observed, and this unusual supramolecular network is fully described here. Moreover, the proligand 1 is non-luminescent at room temperature in acetonitrile whereas complex 2 is luminescent. Closed shell d10–d10 interactions of Ag(I) is expected to be the sources of luminescence.