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.