Synthesis, Crystal Structure, and Characterization of New Tetranuclear Ag(I) Complexes with Triazole Bridges

The self-assembly of Ag(I) ions with 3,5-dimethyl-4-amino-1,2,4-triazole (L1) and 4-salicylideneamino-1,2,4-triazole (L2) gave two novel complexes, [Ag4(μ2-L1)6][Ag4(μ2-L1)6(CH3CN)2](ClO4)8·2H2O (1) and [Ag4(μ2-L2)6(CH3CN)2](AsF6)4·2H2O (2), both of which contain tetranuclearic clusters constructed via Ag(I) ions and six N1,N2-bridged triazoles with a Ag4N12 core. When 4-(6-amino-2-pyridyl)-1,2,4-triazole (L3) was employed, {[Ag4(μ2-L3)4(μ3-L3)2](CF3SO3)4·H2O}n (3), {[Ag4(μ2-L3)4(μ3-L3)2](ClO4)4}n (4), and {[Ag4(μ2-L3)2(μ3-L3)4](PF6)4·CH3CN·0.75H2O}n (5) were isolated. 3 and 4 are 1D polymers, while 5 is a 2D polymer. 1D and 2D coordination polymers are constructed via the self-assembly of Ag4N12 cores as secondary building units (SBUs). The connection of these SBUs can be represented as a ladderlike structure for 1D polymers and a 4.82 net for 2D polymers. Electrospray ionization mass spectrometry measurements and NMR (1H and 13C) studies demonstrate that the tetranuclear SBU retains its integrity and the coordination polymers decompose into the tetranuclear Ag4N12 core in solution. 2 exhibits blue emission in the solid state and green emission in solution at ambient temperature. Strong blue fluorescence for complexes 3−5 in the solid state can be assigned to the intraligand fluorescent emission.