Hydrogen-bonded supramolecular manganese(II) complexes with network and sheet structures bridged by terephthalate unit

Two 1D complexes [Mn(4- methylpyrazole)3(H2O)(tp)]n (2) and [Mn(4-methylpyrazole)4(tp)]n (3) (tp = terephthalate) were synthesized and characterized by means of X-ray analysis and magnetic studies. The molecular structure of 2 reveals that Mn(II) centers with asymmetric coordination surroundings are bridged by crystallographically different tp ligands, forming a 1D chain. The 1D coordination chains are interconnected by hydrogen bonds between free carboxylate oxygen atoms in a chain and hydrogens of pyrazole nitrogen atoms in neighboring chains, leading to a 3D framework. Compound 3 also exhibits a 1D coordination chain which is hydrogen-bonded to adjacent chains, providing a 2D sheet structure. Interestingly, the structures include intra- and interchain hydrogen bonds contributed from N–H groups of the capping 4-methylpyrazole ligands. Magnetic measurements show weak antiferromagnetic interactions with exchange coupling parameters of J = −0.018 cm−1 for 2 and J = −0.062 cm−1 for 3 through the extended tp ligand on the basis of an infinite chain model (H = −J∑Si · Si + 1).