Crystal structure of trans-diacetatobis(2,6-pyridinediylbis(3-pyridinyl)- methanone)-κ2N,N')-copper(II) acetonitrile (1/2), C 42H28CuF6N8O8

Abstract

(Equation presentation) (Table presentation) Source of material All reagents and solvents from commercial sources were used without further purification. 2,6-pyridinediylbis(3-pyridinyl)- methanone was obtained via themethodology according to the literature [1]. 3 mL of a solution of 2,6-pyridinediylbis(3- pyridinyl)methanone (58 mg, 0.2 mmol) in methanol was added dropwise to 3 mL acetonitrile containing Cu(CH3CO2)2.H2O (20 mg, 0.1 mmol) with stirring at room temperature. After three hours, the solution was filtrated and the clear filtrate was left in air for about two weeks. trans-[Cu(C17H11N3O2)2(CF3CO2)2] .2(CH3CN) was obtained as block-shaped crystals (yield: 42.7 mg, 45% based on the ligand). Discussion Pyridyl-based building blocks are widely used in construction various supramolecules of transition metal complexes with distinct topological structures [2]. Among them, dipyridinylmethanone derivates are of interest due to their versatile linkage behavior in coordination supramolecular assemblies [3]. Especially, the coordination chemistry of di-2-pyridinylmethanone (common name di-2-pyridyl ketone, also abbreviated as DPK) [4] and its the positional isomer [5, 6] have attracted wide attention because these ligands can exist in their neat, alcoholated hemiketal and hydrated gem-diol forms in either uncharged or deprotonated state in coordination tometal centers. As a continuation work of the study on the coordination chemistry of 2,6- pyridinediylbis(3-pyridinyl) methanone [1, 7], herein we report one new Cu(II) complex. In the mononuclear complex, the ligand takes a κ2N,N'-chelating mode with the pair of 3-pyridyl rings of each ligand exhibit a dihedral angle of 84.69(3)° (Figure). The Cu(II) located on an inversion center is surround by four N atoms from two of 2,6-pyridinediylbis(3-pyridinyl)methanone ligands and two acetato ligands coordination with one of itsOatoms only. The four N atoms are in the equatorial sites, while the two O atoms are located in axial positions, as shown in Figure (symmetry code a: -x+1, -y+1, -z). Two additional acetonitrile molecules are connected to the complex by C-H...π interactions (C...centroid 3.913(3) / 3.695(2) Å, C-H...centroid 159.4 / 153.7°) [8]. (Table presentation).