Magnetostructural investigations into an S = 1/2 sheet and a tetranuclear butterfly cluster

We present a detailed analysis of the magnetic properties of two Cu(II) coordination compounds with the tetrazole-1-acetate ligand (t1a), previously reported in literature by Yu et al. [Q. Yu, X. Zhang, H. Bian, H. Liang, B. Zhao, S. Yan, D. Liao, Cryst. Growth Des. 8 (2008) 1140] and simultaneously synthesised independently by ourselves. We focus on methods of describing the susceptibility and magnetisation of a ferromagnetically-coupled S = 1/2 square network (2) and a tetranuclear S = 1/2 ‘butterfly’ cluster (4) as well as discussion of the energy levels of such a cluster.