Exploring the Interaction of Pyridine-Based Chalcones with Trinuclear Silver(I) Pyrazolate Complex

The investigation of the interaction of cyclic trinuclear silver(I) pyrazolate [AgPz](3) (Pz = 3,5-bis(trifluoromethyl)pyrazolate) with pyridine-based chalcones (anthracen-9-yl and phenyl-substituted ones) has been performed by IR-, UV-vis, and NMR spectroscopies in the solution. The carbonyl group participates in coordination with metal ions in all complexes. However, the network of pi-pi/M-pi non-covalent intermolecular interactions mainly influences complex formation. The spectral data suggest retaining the structures for all studied complexes in the solution and solid state. E-Z isomerization in the case of anthracene-containing compounds significantly influences the complexation. E-isomer of chalcones seeks the planar structure in the complexes with [AgPz](3). In contrast, the Z-isomer of chalcone demonstrates the chelating coordination of O- and N atoms to silver ions. The complexation of anthracene-containing chalcones allows the switching of the emission nature from charge transfer to ligand-centered at 77 K. In contrast, phenyl-substituted chalcone in complex with macrocycle demonstrates that the emission significantly shifted (Delta = ca. 155 nm) to the low-energy region compared to the free base.