Co(II), Mn(II) and Cu(II)-directed coordination polymers with mixed tetrazolate-dicarboxylate heterobridges exhibiting spin-canted, spin-frustrated antiferromagnetism and a slight spin-flop transition

Three new paramagnetic ion-directed coordination frameworks, {[Co(4)(H(2)O)(2)(μ(3)-OH)(2)(atz)(2)(nip)(2)]·3H(2)O}(n) (1), {[Mn(4)(H(2)O)(2)(μ(3)-OH)(2)(atz)(2)(nip)(2)]·H(2)O·MeOH}(n) (2) and {[Cu(2)(H(2)O)(μ(3)-OH)(atz)(nip)]·2H(2)O}(n) (3), were, respectively, obtained by solvo-/hydrothermal reactions of 5-amino-1H-tetrazole (Hatz), 5-nitroisophathalic acid (H(2)nip) with an inorganic Co(II), Mn(II) or Cu(II) salt. The former two complexes are two-dimensional (2D) covalent layers built from butterfly-shaped tetranuclear M(4)(μ(3)-OH)(2) clusters and double atz(-) and nip(2-) linkers. Whereas complex 3 is a 3D framework with scarcely observed corner-sharing Cu(3)(μ(3)-OH) Δ-chains extended by nip(2-) linkages, in which the anionic atz(-) ligand acts as a reinforcement to consolidate the Δ-chain. Magnetically, due to the interplay of the anisotropy of spin carrier and magnetic exchange interactions from the adjacent spin carriers, the complexes exhibit spin-canted antiferromagnetism with a Néel temperature lower than 2.0 K for 1 and an antiferromagnetic ordering with a slight field-induced spin-flop transition for 2. In contrast, complex 3 with a local Kagomé sublattice displays spin-frustrated antiferromagnetic behavior with magnetic ordering at 16.0 K.