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)2Ni3(bpe)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) Å, b = 12.705(3) Å, c = 17.058(5) Å, β = 117.26(2)°, and Z
= 4. Compound 2 crystallizes in the triclinic system, space group P1̄ (No. 2), with chemical formula C18H20MnN2O4, a = 8.492(2) Å, b = 9.444(2) Å, c = 11.533(3) Å, α = 97.19(1)°, β = 94.64(1)°, γ = 105.02(1)°, 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(1) lies on an inversion center, and its coordination
environment comprises two chelating maleate anions and two bpe nitrogen donors, while the Ni(2) ion is surrounded
by meridionally disposed three bpe 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 Å. Variable-temperature magnetic
susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the
molecule. Compound 2 is composed of Mn2 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 Å), produces an interpenetrated
3D α-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 bpe pathway.