Structural Transformations Induced by Selective and Irreversible Anion Exchanges for a Layered Ag(I) Nitrite Coordination Polymer.

A series of AgI coordination polymers, {[Ag2L][Ag1/2(ONO)2(NO2)1/2](H2O)} n (1), {[AgL](BF4)} n (2), and {[Ag2L2](ClO4)2} n (3), have been prepared by assembly of AgX (X- = NO2 -, BF4 -, and ClO4 -) with 3,4-bis(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L). Single-crystal X-ray diffraction analyses indicate that 1-3 show distinct two-dimensional networks and lattice stacking, with the counteranions [Ag1/2(ONO)2(NO2)1/2]2-, BF4 -, and ClO4 - located in the interlayered voids. Interestingly, when the crystals of 1 were immersed in a water solution of BF4 - or ClO4 - anion, 2 or 3 can be irreversibly formed via anion-driven structural transformation. This process has also been investigated by means of PXRD, elemental analysis, FT-IR, and SEM-EDS, revealing a solvent-mediated mechanism. Moreover, the dynamic anion-exchange behavior is highly anion-selective but cation-independent. [ABSTRACT FROM AUTHOR]