Anion influence on structure and photoluminescence properties of silver(I) complexes with naphthalene-2,3-diyl-diisonicotinate

The anion effects on the formation and photoluminescence (PL) of a series of AgX (X^-= NO₂^-, NO₃^-, ClO₄^-, and PF₆^-) compounds with naphthalene-2,3-diyl-diisonicotinate (L) were investigated. According to the single-crystal X-ray structures, the NO₂^-, NO₃^-, and ClO₄^-anions act as anionic ligands rather than as simple counteranions whereas the PF₆^-anion acts as a simple counteranion. Correspondingly, the dinitroargentate anionic species, Ag(NO₂)₂^-, was observed in the solid state. The PL intensity of the present compounds, moreover, was proportional to the Ag⋯X distance, namely the metallophilicity of the anions. The weak- or non-coordinating anions, ClO₄^-and PF₆^-, could be smoothly exchanged with the NO₂^-or NO₃^-anion, whereas the reverse exchanges did not occur. The compounds' physicochemical properties were characterized by means of infrared (IR) spectroscopy, thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC), and PL.