From One- to Three-Dimensional Architectures: Supramolecular Isomerism of Copper(I) 3,5-Di(4-pyridyl)-1,2,4-triazolate Involving in Situ Ligand Synthesis

Solvothermal treatment of copper(II) salts, ammonia, and 4-cyanopyridine was chosen for the study of supramolecular
isomerism of the target binary copper(I) 3,5-di(4-pyridyl)-1,2,4-triazolate (4-pytz). A 2D coordination network of α-[Cu(4-pytz)]
(1, P21/n, a = 7.9633(5) Å, b = 10.3757(6) Å, c = 13.1054(8) Å, β = 105.673(1)°) was obtained at 120−160 °C using Cu(OH)2
or Cu2(OH)2CO3 as the copper(II) source, while a 3D network of β-[Cu(4-pytz)] (2, Cc, a = 9.4278(5) Å, b = 24.7779(14) Å, c =
10.6761(6) Å, β = 113.025(1)°) was obtained at 100 °C using Cu(OH)2 as copper(II) source. A solvated copper(I) 3,5-di(4-pyridyl)-1,2,4-triazolate [Cu(4-pytz)(NH3)]·4H2O (3, P21/c, a = 9.2065(8) Å, b = 25.574(2) Å, c = 6.8104(6) Å, β = 90.256(2)°) with 1D
coordination structure has also been synthesized at 100 °C using the Cu(NO3)2·3H2O as copper(II) source. Novel hydrogen-bonded
water−ammonia ribbons comprised of fused (H2O)5 and (H2O)4(NH3) pentagons were stabilized in the 1D channels of 3. Networks
1 and 2 show structure-related photoluminescence properties, while 3 is nonemissive under UV irritation.