Diaquadifluorobis(nicotinamide)copper(II) tetrahydrate: hydrogen bonding between ligand fluoride and lattice water

Abstract

Copper(II) fluoride, insoluble in water, dissolves easily in an aqueous solution of nicotinamide from which grow blue crystals of the compound [Cu(na)₂F₂(H₂O)₂]·4H₂O (na = nicotinamide). The X-ray crystal structure of this complex shows not only rare copper–fluoride bonds but equally rare ligand fluoride–lattice water hydrogen bonds. There are three such kinds of bond with R(F ⋯ O)= 2.683, 2.727, and 2.853 Å. Other properties of this compound are also reported.