A novel Cu5II cluster-based 3D magnetic framework with an overall S = 1/2 spin ground state

A 3D (3,8)-connected tfz-d framework with unusual Cu5II clusters periodically extended by 5-nitroisophthalate (nip2−) ligands, {[Cu5(μ3-OH)2(μ2-H2O)2(H2O)4(nip)4]·5H2O}n (1), was hydrothermally synthesized and structurally characterized. Magnetically, the spin frustration in a vertex-sharing triangular aligned Cu5II cluster leads essentially to an overall S = 1/2 spin ground state of 1.