Spacer-Armed Copper(II) Complex Based on Bis(2-pyidyl-1,2,4-triazol-3-yl)butane and 1-Aminoethane-1,1-Diphosphonic Acid

The new complex [Cu4L2(H2AEDP)2(H2O)4] · 34H2O was prepared by the reaction of CuSO4 with bis(2-pyridyl-1,2,4-triazol-3-yl)butane (H2L) and 1-aminoethane-1,1-diphosphonic acid (H4AEDP) and studied by X-ray diffraction (CIF file CCDC no. 1913117). The complex is a spacer-armed dimer in which two dimer subunits formed with participation of diphosphonate dianions are linked to each other via two doubly deprotonated bis(pyridyl)triazoles. The bridging diphosphonate anion exists in the zwitter ion form, bis(triazolyl)butane is coordinated via the nitrogen atoms of the pyridyl moiety and the deprotonated triazole ring. Analysis of the ESR spectrum of the polycrystalline sample attests to weak exchange interactions in the dimeric moieties.