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 (L-1) and 4-salicylideneamino-1,2,4-triazole (L-2) gave two novel complexes, [Ag-4(mu(2)-L-1)(6)][Ag-4(mu(2)-L-1)(6)(CH3CN)(2)](ClO4)(8).2H(2)O (1) and [Ag-4(mu(2)-L-2)(6)(CH3CN)(2)](AsF6)(4). 2H(2)O (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 (L-3) was employed, {[Ag-4(A(2)-L-3)(4)(mu(3)-L-3)(2)](CF3SO3)(4). H2O}(n) (3), {[Ag-4(A(2)-L-3)(4)(mu(3)-L-3)(2)](ClO4)(4)}(n) (4), and {[Ag-4(mu(2)-L-3)(2)(A(3)-L-3)(4)](PF6)(4).CH3CN.0.75H(2)O}(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 4.8(2) net for 2D polymers. Electrospray ionization mass spectrometry measurements and NMR (H-1 and C-13) 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.