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.

将银(I)离子（Ag(I)）与3,5-二甲基-4-氨基-1,2,4-三唑（3,5-dimethyl-4-amino-1,2,4-triazole, L1）和4-水杨醛亚氨基-1,2,4-三唑（4-salicylideneamino-1,2,4-triazole, L2）进行自组装，得到两种新型配合物：[Ag₄(μ₂-L₁)₆][Ag₄(μ₂-L₁)₆(CH₃CN)₂](ClO₄)₈·2H₂O（1）与[Ag₄(μ₂-L₂)₆(CH₃CN)₂](AsF₆)₄·2H₂O（2），二者均包含由银(I)离子与六个N1,N2桥联三唑配体构建的四核簇，其核心为Ag₄N₁₂核。当使用4-(6-氨基-2-吡啶基)-1,2,4-三唑（4-(6-amino-2-pyridyl)-1,2,4-triazole, L3）时，分离得到{[Ag₄(μ₂-L₃)₄(μ₃-L₃)₂](CF₃SO₃)₄·H₂O}ₙ（3）、{[Ag₄(μ₂-L₃)₄(μ₃-L₃)₂](ClO₄)₄}ₙ（4）以及{[Ag₄(μ₂-L₃)₂(μ₃-L₃)₄](PF₆)₄·CH₃CN·0.75H₂O}ₙ（5）。其中3和4为一维聚合物，5则为二维聚合物。一维与二维配位聚合物均以Ag₄N₁₂核作为次级结构单元（secondary building units, SBUs）自组装构建而成。这类次级结构单元的连接方式：一维聚合物呈梯状结构，二维聚合物则对应4.82拓扑网络。电喷雾电离质谱（electrospray ionization mass spectrometry）与核磁共振氢谱、碳谱（¹H和¹³C NMR）测试结果表明，四核次级结构单元在溶液中可保持结构完整性，而配位聚合物会在溶液中解离为Ag₄N₁₂核。配合物2在室温固态下呈现蓝色发射，在溶液中则呈现绿色发射。配合物3~5在固态下具有强蓝色荧光，其发光可归因为配体内荧光发射。