Synthesis, Crystallographic Structure, DFT Calculations and Hirshfeld Surface Analysis of a Fumarate Bridged Co(II) Coordination Polymer

Abstract

A 1-D coordination polymer catena [μ-fumaratobis (nicotinamide-κN)diaquacobalt (II)], (C<inf>16</inf>H<inf>18</inf>CoN<inf>4</inf>O<inf>8</inf>)<inf>n</inf>, [Co(fum) (nia)<inf>2</inf>(H<inf>2</inf>O)<inf>2</inf>] or [Co(μ-C<inf>4</inf>H<inf>2</inf>O<inf>4</inf>) (C<inf>6</inf>H<inf>6</inf>N<inf>2</inf>O)<inf>2</inf>(H<inf>2</inf>O)<inf>2</inf>]<inf>n</inf> was synthesized and structurally characterized. The crystal structure is triclinic, space group P1¯ with parameters a = 7.2362 (8) Å, b = 7.5466 (8) Å, c = 9.0027 (10) Å, α = 109.582 (8)°, β = 103.132 (9)°, γ = 97.681 (9)°, V = 439.13 (9) Å3, Z = 1. The asymmetric unit occurs from a CoII cation coordinated by the carboxylate O atom of the fumaric acid unit, N atom of the nicotinamide unit and together with one water molecule. In the title complex, CoII ion is octahedrally coordinated by two O atoms of the bridging fumarate dianion, two N atoms of nicotinamide molecules and two O atoms of water molecules. Theoretical calculations were obtained by using Density Functional Theory (DFT) methods. The vibrational frequencies and structural parameters were calculated by using DFT/B3LYP/6-311G** basis set in ground state. Molecular Electrostatic Potential (MEP) map and the frontier molecular orbitals (HOMO-LUMO) of the compound were created by using the optimized structures. The results of theoretical study using the DFT method at the B3LYP/6–311G** level are in good agreement with the experimental data. In the crystal, molecules are linked into a three-dimensional network by O–H⋯O and N–H⋯O hydrogen bonds. Hirshfeld surface analysis (d<inf>norm</inf> surfaces and two-dimensional fingerprint plots) for the title compound were performed and discussed. © 2018 Elsevier B.V.