Structural Diversity of Silver(I) 4,6-Dipyridyl-2-Aminopyrimidine Complexes: Effect of Counteranions and Ligand Isomerism

Using two ligands, 4,6-bis(2-pyridyl)-2-aminopyrimidine (L1) with two N,N‘-chelating sites and 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (L2) (as the isomer of L1) containing one chelating site and one bridging unit, a series
of novel Ag(I) complexes varying from zero- to two-dimensions have been prepared and their crystal structures
determined via single-crystal X-ray diffraction. The two ligands are employed for the first time in coordination
chemistry. The structures of compounds 1−3 are directed by the counteranions adopted in the reaction system: 
The reaction of L1 with AgNO3 yielded a dimer [Ag2L12](NO3)2 (1). The reaction of L1 with AgCF3SO3 led to a
one-dimension “V-shaped” chain {[AgL1](CF3SO3)}n (2). When AgSCN was used, a one-dimension ladder {[Ag2L1(SCN)2]·H2O}n (3) was obtained. While ligand L2 reacted with AgNO3, a two-dimension {[Ag2(L2)2](NO3)2·H2O}n
(4) was prepared with the help of an argentophilic interaction. Compounds 1−4 display room-temperature
photoluminescence.

本研究选用两种配体（ligand）：具有两个N,N'-螯合位点（N,N'-chelating sites）的4,6-双(2-吡啶基)-2-氨基嘧啶（L1），以及作为L1同分异构体、含一个螯合位点和一个桥联单元（bridging unit）的4-(2-吡啶基)-6-(4-吡啶基)-2-氨基嘧啶（L2），成功合成了一系列从零维到二维的新型Ag(I)配合物，并通过单晶X射线衍射（single-crystal X-ray diffraction）测定了其晶体结构。
这两种配体均为首次应用于配位化学领域。化合物1~3的结构由反应体系中采用的抗衡阴离子（counteranions）调控：L1与硝酸银（AgNO₃）反应得到二聚体配合物[Ag₂L₁₂](NO₃)₂（1）；L1与三氟甲磺酸银（AgCF₃SO₃）反应得到一维"V形"链状配合物{[AgL₁](CF₃SO₃)}ₙ（2）；当使用硫氰酸银（AgSCN）时，得到一维梯状配合物{[Ag₂L₁(SCN)₂]·H₂O}ₙ（3）。当配体L2与硝酸银反应时，借助亲银相互作用（argentophilic interaction），成功制备得到二维配合物{[Ag₂(L₂)₂](NO₃)₂·H₂O}ₙ（4）。化合物1~4均表现出室温光致发光特性。