The first coordination compound of 6-fluoronicotinate: the crystal structure of a one-dimensional nickel(II) coordination polymer containing the mixed ligands 6-fluoronicotinate and 4,4′-bipyridine

Abstract

A one-dimensional nickel(II) coordination polymer with the mixed ligands 6-fluoronicotinate (6-Fnic) and 4,4′-bipyridine (4,4′-bpy), namely,catena-poly[[diaquabis(6-fluoropyridine-3-carboxylato-κO)nickel(II)]-μ-4,4′-bipyridine-κ2N:N′] trihydrate], {[Ni(6-Fnic)2(4,4′-bpy)(H2O)2]·3H2O}n, (1), was prepared by the reaction of nickel(II) sulfate heptahydrate, 6-fluoronicotinic acid (C6H4FNO2) and 4,4′-bipyridine (C10H8N2) in a mixture of water and ethanol. The nickel(II) ion in1is octahedrally coordinated by the O atoms of two water molecules, two O atoms fromO-monodentate 6-fluoronicotinate ligands and two N atoms from bridging 4,4′-bipyridine ligands, forming atransisomer. The bridging 4,4′-bipyridine ligands connect symmetry-related nickel(II) ions into infinite one-dimensional polymeric chains running in the [1\overline{1}0] direction. In the extended structure of1, the polymeric chains and lattice water molecules are connected into a three-dimensional hydrogen-bonded networkviastrong O—H...O and O—H...N hydrogen bonds, leading to the formation of distinct hydrogen-bond ring motifs: octamericR88(24) and hexamericR86(16) loops.