Design and construction of coordination polymers based on 2,2′-dinitro-4,4′-biphenyldicarboxylate and semi-rigid N-donor ligands: diverse structures and magnetic properties

Abstract

Eight 2D and 3D coordination polymers, [Mn(NBPDC)(1,4-bimb)]_n (1), [Zn(NBPDC)(1,4-bimb)]_n (2), [Cd(NBPDC)(1,4-bimb)]_n (3), [Mn₂(NBPDC)₂(1,3-bimb)(H₂O)]_n (4), {Zn(NBPDC)(1,3-bimb)}_n (5), [Cd₂(NBPDC)₂(1,3-bimb)₂(H₂O)]_n (6), [Mn(NBPDC)(4,4′-bimbp)]_n (7), and [Cd₂(NBPDC)₂(4,4′-bimbp)₂]_n (8), (NBPDC = 2,2′-dinitro-4,4′-biphenyldicarboxyl acid, 1,4-bimb = 1,4-bis(imidazol-1-ylmethyl) benzene, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl) benzene, and 4,4′-bimbp = 4,4′-(bis(imidazol-l-ylmethylene)) biphenyl), have been prepared and structurally characterized. In these coordination polymers, NBPDC and three N-donor ligands link different metal ions and SBUs to construct diverse architectures. Compounds 1 and 3 are isomorphic, showing a two-fold interpenetrating pcu topology. Compound 2 presents a 2D (4, 4) net. Compound 4 is a hex framework built by the linkage of ligands with infinite rod-shaped SBUs. Compound 5 presents a unprecedented eight-fold interpenetrating sra topology. Compound 6 exhibits a unique 2D {6³}{6⁵.8} topology with four-fold interpenetrating structure. Compound 7 presents a 3D hex topology, and compound 8 shows a (4, 4) net. The magnetic properties of compounds 1, 4, and 7 have been characterized. Compound 1 displays interesting spin-canting antiferromagnetism and metamagnetism simultaneously. Compound 7 exhibits spin-canting antiferromagnetism.