Effect of the Pyridyl Orientation on Coordination Assembly: Construction of Ag(I) Coordination Polymers with Electrochemical and Antibacterial Behaviors

Three racemic ligands (L1–L3) containing 1,2-dihydroquinazoline units have been designed and synthesized as a continuation of our previous research work. Six Ag(I) coordination polymers, {[AgL1]BF4·3MeCN}n (1), {[Ag2(L1)2](NO3)2·MeCN·H2O}n (2), {[Ag2(L2)2(μ2–N2)](NO3)2·2H2O}n (3), {[Ag2(L2)2(μ2–N2)](BF4)2·2H2O}n (4), {[Ag(L3)2]tosylate·2MeCN·H2O}n (5), and {[Ag2(L3)4](PF6)2·2MeOH}n (6), were synthesized upon reaction of these ligands with different Ag(I) salts. The structural diversity of the resulting complexes revealed the chiral self-discrimination or self-recognition processes of the racemic ligands when coordinated to Ag(I) ions. More importantly, the pyridyl orientation in the ligands has a crucial effect on the resulting structures of these complexes. In addition, with the combination of the biological activity of the 1,2-dihydroquinazoline derivatives and the redox behaviors of their resulting Ag(I) complexes, we investigated their antibacterial activity against two bacteria (MDREC and MRSA), and the synthesized Ag(I) complexes showed satisfactory antibacterial properties.