Bis(7-amino-1,2,4-triazolo[1,5-a]pyrimidin-4-ium) bis(oxalato-κ2O1,O2)cuprate(II) dihydrate

Abstract

The structure of the title ionic compound, (C5H6N5)2[Cu(C2O4)2]·2H2O, consists of a centrosymmetric copper(II) oxalate dianion, two monoprotonated molecules of the adenine analog 7-amino-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and two water molecules of crystallization. The CuII ion, located on an inversion center, exhibits a sligthly distorted square-planar coordination geometry, in which two oxalate anions bind in a bidentate fashion. The triazolopyrimidine ligand is protonated at the N atom in position 4, instead of its most basic N atom in position 3. This fact may be explained by the network stability, which is provided through the formation of a two-dimensional wave-like network parallel to (50overline1) by N—H...O, O—H...N and O—H...O hydrogen bonds. These nets are further connected via C—H...O interactions.