New High-Nuclear Coordination Complexes Constructed by 2-Hydroxymethylpyridine: From Antiferromagnetic to Spin Glass and Ferromagnetic Behavior

Abstract

Five new nuclear coordination complexes based on a 2-hydroxymethylpyridine (Hhmp) ligand, [Cu4­(hmp)4­(CHOO)2­(H2­O)2]­(ClO4)2·2H2O (1), [Cu8­(hmp)8­(CHOO)4­(CH3­CN)2­(H2­O)4]­(ClO4)4·2CH3­CN (2), {[Cu2­(hmp)2­(CHOO)­(H2O)]­ClO4·H2­O}n (3), [Co9­(hmp)6­(CHOO)6­(CO3)2­(H2­O)6]­(ClO4)2·11H2O (4), and [Co9­(hmp)6­(CHOO)7­(CO3)2­(H2­O)5]­ClO4·CH3­CN·12H2O (5), have been synthesized through evaporation at room temperature. As expected, by changing the ratio of the mixed solvent complexes, 1–3 successfully grow from a [Cu4O4] monocubane (1) to octanuclear double-cubane (2), which then further extends into polycubane (3, one-dimensional chain) via bridging ligands of formate. By changing the metal source, complexes 4 and 5 with a similar {Co9} cluster are successfully obtained. One water molecule coordinated with CoII in one [Co4O4] core of complex 4 has been replaced by a formate anion in complex 5, resulting in the {Co9} cluster with +2 and +1 charges, respectively. The change of charges on the clusters results in different cluster alignments, changing the intermolecular interactions in 4 and 5. Magnetic measurements show that antiferromagnetism interaction changes into weak ferromagnetic interaction in complexes 1–3, while the antiferromagnetic behavior turns to glass spin in complexes 4 and 5.