Two manganese(II) complexes based on anthracene-9-carboxylate: Syntheses, crystal structures, and magnetic properties

To explore the influence of the anthracene ring skeleton, with a large conjugated pi-system, on the structures and properties of its complexes, two Mn-II complexes with anthracene-9-carboxylate ligand were synthesized and structurally characterized: {[Mn(L)(2)(H2O)(2)](H2O)}(infinity) (1) and [Mn-2(L)(4)(phen)(2)(mu-H2O)](CH3OH) (2) (L = anthracene-9-carboxylate and phen = 1,10-phenanthroline). Complex (1) has a one-dimensional (1D) chain structure that is further assembled to form a two-dimensional (2D) sheet, and then an overall three-dimensional (3D) network by pi center dot center dot center dot pi stacking and/or C-H center dot center dot center dot pi interactions. Complex (2) makes a dinuclear structure by incorporating the chelating phen ligand, which is further interlinked via inter-molecular pi center dot center dot center dot pi stacking and C-H center dot center dot center dot pi interactions to generate a higher-dimensional supramolecular network along the different crystallographic directions. The results reveal that the bulky anthracene ring skeleton in L, by virtue of intra-and/or inter-molecular pi center dot center dot center dot pi stacking and C-H center dot center dot center dot pi interactions, plays an important role in the formation of complexes (1) and (2). The magnetic properties of (1) and (2) were further investigated. As expected, the very long inter-metallic separations result in weak magnetic coupling, with the corresponding coupling constant values of J = -10 cm(-1) for (1) and J = -2.46 cm(-1) for (2).