Well-Designed Strategy To Construct Helical Silver(I) Coordination Polymers from Flexible Unsymmetrical Bis(pyridyl) Ligands: Syntheses, Structures, and Properties

摘要

ABSTRACT: In this Article, self-assembly of AgX (X = NO3n− andnClO4n−) salts and four flexible unsymmetrical bis(pyridyl) ligands,nnamely, N-(pyridin-2-ylmethyl)pyridin-3-amine (L1), N-(pyridin-3-nylmethyl)pyridin-2-amine (L2), N-(pyridin-4-ylmethyl)pyridin-2-namine (L3), and N-(pyridin-4-ylmethyl)pyridin-3-amine (L4),nresults in the formation of eight helical silver(I) coordinationnpolymers, [Ag(L)(NO3)]n [L = L1 (1), L2 (2), L3 (3), L4 (4)] andn[Ag(L)(ClO4)]n [L = L1 (5), L2 (6), L3 (7), L4 (8)], which havenbeen characterized by elemental analysis, IR, TG, PL, and powdernand single-crystal X-ray diffraction. The alternating one-dimensionaln(1-D) left- and right-handed helical chains are included in achiralncomplexes 1−3 and 5−8. By contrast, the ligand L4 only alternately bridges Ag(I) cation to form the 1-D right-handed helicalnchain in complex 4. The pitches of these helical chains locate in the range 5.694(5)−17.016(6) Å. Meanwhile, the present fournunsymmetrical bis(pyridyl) ligands in the eight complexes present diverse cis−trans and trans−trans conformation and facilitatenthe construction of helical structures. Moreover, the solid-state luminescent emission intensities of the perchlorate-containingncomplexes are stronger than those of nitrate-containing complexes at room temperature.