Anion-directed self-assembly of Cu() coordination compounds with tetrazole-1-acetic acid: syntheses in ionic liquids and crystal structures

Reaction of tetrazole-1-acetic acid (1-Htza) with a Cu( ii ) salt in ionic liquids with different anions, [BMIM]X (BMIM = 1-butyl-3-methylimidazolium; X = Br − , BF 4 − , NTf 2 − (NTf 2 − = bis((trifluoromethyl)sulfonyl)amide)), afforded five Cu( ii ) coordination compounds, [Cu 2 (1-tza) 4 ]Br·H 3 O·1/3H 2 O ( 1 ), [Cu 2 (1-tza) 4 ]BF 4 ·H 3 O·H 2 O ( 2 ), [Cu(μ 2 -Cl)(1-tza)(1-Htza)(H 2 O)]·0.5H 2 O ( 3 ), [CuCl(μ 2 -Cl)(1-Htza) 2 (H 2 O)]·H 2 O ( 4 ), and [CuCl 2 (1-Htza) 2 ]·H 2 O ( 5 ). Single-crystal X-ray diffraction analyses reveal that 1-5 display various structures, and the 1-tza − ligand exhibits diverse coordination modes. Compounds 1 and 2 possess higher dimensional structures (a 2-D neutral Kagomé topology network for 1 and a 3-D lvt-type topology framework for 2 ) with fully deprotonated 1-tza − ligands. Compounds 3-5 display lower dimensional structures (1-D, 1-D and 0-D for 3 , 4 and 5 , respectively) with partly or fully protonated 1-Htza. The anions of ionic liquids have significant influences on the final molecular architectures, which arise from different water miscibility of ionic liquids. Anions of ionic liquids with different water miscibility have significant effects on the structures of Cu-1-Htza coordination compounds.