Diverse manganese(ii) coordination polymers derived from achiral/chiral imidazolium-carboxylate zwitterions and azide: Structure and magnetic properties

Five Mn(ii) coordination polymers containing azide and carboxylate as simultaneous bridges have been derived from different imidazolium-carboxylate zwitterionic ligands: 1-methyl-3-(carboxylatomethyl)imidazolium (L1), 1,3-bis(carboxylatomethyl)imidazolium (L2), (S,S)-, (R,R)-, and (R,S)-1,3-bis(1-carboxylatoethyl)imidazolium (S,S-L3, R,R-L 3 and R,S-L3). The compounds are formulated as [Mn(L 1)(N3)2] (1), [Mn(L2)(N 3)] (2), [Mn(R,R-L3)(N3)]·0.5CH 3OH (3-R), [Mn(S,S-L3)(N3)]·0.5CH 3OH (3-S), [Mn(R,S-L3)(N3)] (4). In compound 1, the neutral monocarboxylate zwitterion ligand (L1) leads to uniform chains with bis(azide)(carboxylate) bridges. For compounds 2-4, the anionic dicarboxylate zwitterions L2 and L3 lead to (azide)bis(carboxylate) bridges, but the overall coordination networks are different. In 2 and 3-S (or 3-R), chains with the (azide)bis(carboxylate) bridges are connected by L2 and S,S-L3 (or R,R-L 3), respectively, to give achiral and chiral 2D coordination networks with different connecting topologies. In compounds 4, which is derived from the mesomeric ligand R,S-L3, linear trinuclear units with the (azide)bis(carboxylate) bridges are linked by μ-1,3 azides to give 2D layers, and the layers are pillared into a 3D framework by the 1,3- dimethyleneimidazolium tethers. Magnetic analyses suggested that compounds 1-3 behave as 1D antiferromagnetic systems, while 4 shows canted antiferromagnetism with weak ferromagnetic ordering below TC = 12.4 K. © The Royal Society of Chemistry 2013.