Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand

Two novel inorganic-organic hybrid 3D extended networks of Ni(II) and Mn(II) having molecular formulas [(maleate)(2)Ni-3(bPG)(4)(H2O)(4)](NO3)(2).H2O (1) and [(adipate)Mn(bpe)] (2) (bpe = 1,2-bis(4-pyridyl)ethane), respectively, have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature (300-2 K) magnetic measurements. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), with chemical formula C56H62N10Ni3O19, a = 30,955(4) Angstrom, b = 12.705(3) Angstrom, c = 17.058 Angstrom, beta = 117,26(2)degrees, and Z = 4, Compound 2 crystallizes in the triclinic system, space group P (1) over bar (No. 2), with chemical formula C18H2O-MnN2O4, a = 8.492(2) Angstrom, b = 9.444(2) Angstrom, c = 11.533(3) Angstrom, alpha = 97.19(1)degrees, beta = 94.64(1)degrees, gamma = 105.02(1)degrees, and Z = 2. The structure determination reveals for both a 3D network. Compound 1 contains two crystallographically independent Ni(II) ions in different octahedral environments. Ni(l) lies on an inversion center, and its coordination environment comprises two chelating maleate anions and two lope nitrogen donors, while the Ni(2) ion is surrounded by meridionally disposed three lope N atoms, two water molecules, and one oxygen donor from the dicarboxylate anion. Of the three crystallographic independent bpe ligand, one presents an anti and the others a gauche conformation. The corresponding N-to-N distances are 9.344, 6.543, and 6.187 Angstrom. Variable-temperature magnetic susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the molecule. Compound 2 is composed of Mn-2 dimer units linked by adipate anions to form corrugated 2D sheets which, on interconnection through bpe (anti conformation, N-to-N distance of 9.391 Angstrom), produces an interpenetrated 3D alpha-polonium-related type net. Complex 2 reveals to be antiferromagnetic fitting data using a dimeric Mn(II) model that considers negligible magnetic transmission through the carbon skeleton of adipate and the lope pathway.