Anion-directed assembly and crystal transformation of Ag(I) coordination polymers with a versatile tripyridyltriazole ligand 3,4-bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

• A series of Ag(I) coordination polymers with a versatile tripyridyltriazole ligand can be regulated by the counterions.
• Flexible conformations and coordination modes are observed for the ligand.
• Single-crystal-to-single-crystal (SC–SC) transformation induced by the anion-exchange process is achieved.

A series of distinct Ag(I) coordination polymers, namely {[Ag2(L224)(H2O)3](SiF6)(H2O)4}n (1), {[Ag2(L224)2(NO3)](NO3)(H2O)}n (3), {[Ag2(L224)(OOCC6H5)(H2O)](NO3)(H2O)2}n (4), and {[Ag(L224)2](CF3SO3)(H2O)0.25}n (5) have been synthesized by assembling a versatile ligand 3,4-bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L224) with different Ag(I) salts. Their diverse 1D and 2D coordination arrays indicate the critical role of counterions in structural assemblies. Interestingly, single-crystal-to-single-crystal (SC–SC) transformation from 1 to {[Ag2(L224)(CF3COO)2(H2O)](H2O)}n (2) will occur in the water solution of Ag(CF3COO). Structural comparison and mechanism of SC–SC transformation are discussed. These Ag(I) coordination polymers show enhanced ligand-based solid-state fluorescent emissions.

The anions of metal salts (SiF62−, NO3−, NO3−/C6H5COO–, and CF3SO3−) are found to be critical to construct a series of distinct Ag(I) coordination polymers with a tripyridyltriazole ligand. Significantly, single-crystal-to-single-crystal transformation can also be achieved through anion-exchange of SiF62− by CF3COO−.Figure optionsDownload as PowerPoint slide