Luminescent Ag^I Complexes with 2,2′‐Bipyridine Derivatives Featuring [Ag‐(CF₃)₂Pyrazolate]₄ Units

Abstract

The tetranuclear silver(I) 3,5-bis(trifluoromethyl)pyrazolate adducts with 2,2′-bipyridine derivatives were prepared by the reaction of trinuclear metal complex with the diimines. It was shown that the product structure depends on the reagents ratio: mono-and bisdiimine complexes were synthesized. Compounds obtained possess green phosphorescence in the [a] A. N. Nesmeyanov Institute of Organoelement Compounds, 4855 solid state. The short intramolecular Ag···Ag distances (≤ 3 Å) make possible electronic communication between the metal atoms which leads to the dual emissive behavior mainly due to the 3 LC phosphorescence with the impact of 3 MLCT. The behavior observed was rationalized by the TD-DFT study.by N,N-ligand. [7f ] Despite the high potential of silver pyrazolate adducts with chelating diimines to exhibit the photophysical properties the examples of such complexes are rare. [7b,7f,7i] Herein we report on the synthesis, structures and photophysical properties of a series of silver(I) 3,5-bis(trifluoromethyl) pyrazolate [3,5-(CF 3 ) 2 Pz], Pz adducts with 2,2′-bipyridine (L I ), 4,4′-dimethyl-2,2′-bipyridine (L II ) and 2,2′-biquinoline (L III ). The influence of the reagents ratio and the ligand structure on the complexation pattern, as well as the relationship between the complexes structures and their photophysical properties were studied. It was shown that the difference in the intramolecular non-covalent silver-silver interactions influences the photophysical behavior.

Tetranuclear Copper(I) and Silver(I) Pyrazolate Adducts with 1,1′-Dimethyl-2,2’-bibenzimidazole: Influence of Structure on Photophysics

“…According to previous results on the interaction of trinuclear Cu(I) and Ag(I) complexes with diimines [ 40 , 45 , 46 ], the reaction outcome depends on the macrocycle/ligand ratio. Therefore, we tested three possibilities for 1,1′-dimethyl-2,2’-bibenzimidazole, taking 0.75, 1, and 1.5 equivalents of L relative to the macrocycle.…”

“…The measured phosphorescence spectra of complexes 1 , 3 , and 4 and the established lifetimes of all complexes in the microsecond domain ( Table 1 ) prove this suggestion. It should be noted that such long-lived phosphorescence was observed for silver pyrazolate adducts with diimines [ 45 , 46 ]. Interestingly, in the case of complex 1 , the intensity of the phosphorescence band was negligibly small in comparison with the fluorescence band.…”

“…Thus, the interactions of cyclic trinuclear complexes with nitrogen- or phosphorus-containing ligands lead to the formation of heteroleptic metal pyrazolates of different structures, depending on the reagent ratios [ 39 , 40 , 41 , 42 , 43 , 44 ]. The complexation of macrocycles with diimines (bipyridine- or phenanthroline-type ligands) allows di-, tetra-, or pentanuclear complexes to be obtained [ 40 , 45 , 46 ].…”

Dinuclear Silver(I) Nitrate Complexes with Bridging Bisphosphinomethanes: Argentophilicity and Luminescence

“…1.02 1Colorless crystals of complex 1 was obtained by slow evaporation of their DCM/hexane (v/v = 2:1) solutions at ca. 5 • C. Complex 1 features a chair form of the eight-member cyclic [AgPCP] 2 core ( Figure 1), in which silver atom is coordinated to four atoms (two P dppm (2.396 2 Ag-Ag bond length (2.9812(7) Å) was in the range of shared argentophilic interactions [27][28][29] being non-significantly longer than that present in the literature (av. 2.93 Å).…”