Syntheses, Structures, and Porous/Luminescent Properties of Silver 3-Alkyl-1,2,4-Triazolate Frameworks with Rare 3-Connected Topologies.

Self-assembly of silver(I) ion with 3-alkyl-1,2,4-triazoles in different solvents yielded four new metal azolate frameworks (MAFs), namely, [Ag(mtz)] (1, Hmtz = 3-methyl-1,2,4-triazole), [Ag(etz)] (2, Hetz = 3-ethyl-1,2,4-triazole), [Ag4(etz)4]·H2O (3·H2O), and [Ag4(ptz)4] (4, Hptz = 3-propyl-1,2,4-triazole). Single-crystal X-ray diffraction revealed that Ag(I) ions and triazolates in these MAFs are all three-coordinated to give rare 3-connected framework topologies. Although 1and 2possess the same uniform (10,3)-d (utp) topology, variation of the alkyl groups renders substantially different coordination structures. On the other hand, 3·H2O and 4, also bearing different alkyl substituents, are isomorphours, and can be simplified as the same uninodal sqc5603 topology (point and vertex symbols are 82.10 and 8.82.12, respectively). Due to the relatively short alkyl length, the coordination framework of 3·H2O contains one-dimensional narrow channels. According to thermogravimetry and single-crystal X-ray diffraction, 3·H2O can be dehydrated without framework collapse. Although guest-free 3does not adsorb N2at 77 K, 3·H2O can undergo guest exchange, and 3can adsorb solvent vapor, to give CH2Cl2- and CH3CN-included crystals. Comparing the single-crystal structures of 3·H2O, 3, 3·CH2Cl2, and 3·CH3CN reveals the framework flexibility of 3. These materials also show interesting structure- and guest-dependent photoluminescent properties. [ABSTRACT FROM AUTHOR]