An anti-ferromagnetic terephthalate-bridged trigonal prismatic dinuclear manganese(II) complex: Synthon of rare anion⋯ π interaction promoting dimensionality

Abstract

A dinuclear compound [Mn2(L)2(μ-tp)](PF6)2⋅3.57H2O (1) [L = N,N′-(bis(pyridin-2-yl)benzy-lidene)-1,3-propanediamine and tp = terephthalate dianion] has been isolated and characterized on the basis of microanalytical, spectroscopic and other physicochemical properties. X-ray structural study showed interesting bis(bidentate) bridging motif of tp in the dicationic dinuclear unit [Mn2(μ-tp)]2+. Each manganese(II) centre adopts a rare distorted trigonal prismatic geometry with an MnN4 O 2 chromophore. Chelation of the tetradentate Schiff base (L) along with bis(bidentate) bridging of two O atoms of tp complete hexacoordination around each manganese(II) centre. The dinuclear units of 1 are associated through cooperative C-H⋯F hydrogen bonds and π ⋯ π, C-H⋯ π and rare anion⋯ π interactions to promote the dimensionality in a graded manner. Variable temperature magnetic susceptibility measurement of 1 in the 2–300 K temperature range revealed weak anti-ferromagnetic interaction presumably due to long bridging arm of tp. Synthesis, crystal structure and magnetic behavior of a dinuclear manganese(II) terephthalate complex with tetradentate N-donor Schiff base has been described. Interesting trigonal prismatic geometry around metal ion was observed in the complex. The dinuclear units of 1 are the source of rare anion⋯ π interactions to promote the dimensionality of compound.