Antiferromagnetic ordering in a novel five-connected 3D polymer Cu2 (2, 5-Me2pyz) N (CN) 24n (2, 5-Me2pyz2, 5-dimethylpyrazine) Electronic supplementary information (ESI) available: plot of the temperature dependence of the ac susceptibility (Fig. S1). See http: //www. rsc. org/suppdata/nj/b1/b111012h/