Magnetic couplings mediated through the non-covalent interactions

Abstract

Density functional theory (DFT), broken symmetry (BS) approach, was applied in order to determine the mechanism of couplings through the non-covalent interactions for the series of coordination compounds bridged by strong hydrogen bonds, namely [Mn(F)(4)HF2](2-), [Ni(HF2)(pyz)(2)](-), [Cu(HF2)(pyz)(2)](-), [Cu2F(HF)(HF2)(pyz)(4)](2-), [CuF2(H2O)(2)(pyz)] (where pyz = pyrazine), [Cu-2(php)(2)(H2O)(2)](2+) (php = 6-(pyridine-2-ylhydrazonomethyl)phenol), [Cu(L-1)(H2O)](+) (HL1 = 1-(2-hydroxyethylaminomethyl)-3-hydroxyethyl-1,3-diazacyclohexane), multi copper active centers from Escherichia coli multi-copper oxidase and peptidylglycine alpha-hydroxylating monooxygenase, and [CuBr4](2-). In most investigated structures, main function of hydrogen bonds is to achieve reasonable distances between the interacting units, which are necessary for the favorable superexchange interactions. Antiferromagnetic couplings in Cu(II) complexes decrease with increasing distance between two monomer units. This work can help in rational design of new materials with this kind of bridging ligands. (c) 2012 Elsevier Ltd. All rights reserved.