Abstract
The synthesis, together with molecular structure and characterization of mu(3)-hydroxidobis(nitrato)tris (mu-pyrazolato)tetrakis(pyrazole)tricopper(11) monohydrate ([Cu-3(OH)(pz)(3)(Hpz)(4)(NO3)(2)](H2O)) is presented and discussed, also in comparison with some related pyrazole nitrate compounds. The peculiar intramolecular hydrogen-bond stabilization for the cluster with as many as 6 intramolecular hydrogen bonds is considered in detail. The non-bonding water solvate bridges between a coordinating nitrate and hydroxide, and intermolecularly with the pyrazole NH from a neighboring unit. Ligand-field, EPR and infrared spectra are discussed in the context of the trinuclear Cu unit. Low-temperature magnetic susceptibility shows a strong antiferromagnetic exchange, resulting in a spin of S = 1/2 at low T, similar to earlier reported related compounds. (C) 2014 Elsevier Ltd. All rights reserved.