One-Dimensional Coordination Polymers of Silver(I) with Aminomethylpyridines. Example of a Triple Helical Infinite Chain

Crystal structures of the three isomeric compounds Ag(2-amp)ClO4 (1), Ag(3-amp)ClO4 (2), and Ag(4-amp)ClO4 (3) reveal different packing arrangements of one-dimensional (1-D) infinite chain coordination polymers,
formed in each case by the coordination of Ag to the pyridine N and amino N atoms from two different ligand
molecules. 1:  triclinic, space group P1̄, with a = 7.672(6) Å, b = 11.1401(11) Å, c = 11.322(4) Å, α = 91.207(14)°, β = 105.52(4)°, γ = 90.48(2)°, and Z = 2. 2:  monoclinic, space group P21/c, with a = 8.345(4) Å, b =
8.6748(7) Å, c = 26.056(9) Å, β = 97.96(4)°, and Z = 4. 3:  hexagonal, space group P6522, with a = 9.3154(11)
Å, c = 39.313(5) Å, and Z = 12. 1 consists of zigzag chains, while 2 is made up of triple helical chains generating
a tunnel space large enough to hold half the anions inside it. 3 has a highly symmetrical arrangement of 12
crystallographically equivalent chains held by weak Ag···Ag bonds. The crystal packing of the 1-D polymers in
this case may be described in terms of either helical ladders or stacked double layers.