Abstract
Hydrothermal reaction of FeCl3 and nicotinic acid gave a novel, trinuclear metal-nicotinato complex Fe3(O)(C6NO2H5)6(H2O)3·3H2O·7Cl. An X-ray crystal structure analysis reveals that it features an isolated structure. The crystal belongs to the rhombohedral, space group R--3c with a = b = 19.9410(6) Å, c = 30.505(1) Å, V = 10504.9(6) Å3, Z = 6, C36H42Cl7Fe3N6O19, Mr = 1278.46, Dc = 1.213 g cm−3, S = 0.980, μ(MoKα) = 0.936 mm−1, F(000) = 3894, R = 0.0694 and wR2 = 0.1579. The iron atom has a slightly distorted octahedral geometry, coordinated by six oxygen atoms. All three octahedrons interconnect to each other via corner-sharing an oxygen atom, yielding an oxo-centred, trinuclear iron cluster. The [Fe3(O)(C6NO2H5)6(H2O)3]7+ species, lattice water molecules and chloride ions are held together via hydrogen bonds to construct a three-dimensional (3-D) open framework, with a large void space (2803.9 Å3) corresponding to 26.7% of the unit-cell volume (10504.9 Å3).