A novel layered and pillared topology in a 3D open framework: synthesis, crystal structure and magnetic propertiesElectronic supplementary information (ESI) available: Fig. S1: showing the brick-walled shaped view of the [{Cu3(malonate)2(H2O)2}]n layer; Fig. S2: space-filled diagram showing channels viewed down x-axis. See http://www.rsc.org/suppdata/nj/b2/b208650f/