Crystal structure of bis(N-(2-aminoethyl)salicylaldiminato)iron(III) isothiocyanide, [Fe(C9H11N2O)2] [NCS]

Abstract

Ci9H22FeN 5 0 2 S, triclinic, PI (no. 2), a = 9.613(1) Ä, b = 9.913(1) Ä, c = 10.869(2) A, a = 84.958(2)°, β = 89.047(2)°,γ = 86.098(1)°, V= 1029.3 Ä 3 ,Ζ = 2, R#(F) = 0.038, wR K ((F 2 ) = 0.099, T= 291 K. Source of materialThe mixture of FeCh · 4H 2 0 (0.122 g, 0.5 mmol) and NH4SCN (0.192 g, 1 mmol) were refluxed in anhydrous methanol (15 mL) at a temperature of 60 °C for 50 min, then were added 20 mL methanol solution of freshly distilled salicylaldehyde and ethylenediamine simultaneously. The mixture was stirred for 5 h, then filtered. The resulting clear solution was diffused with ethyl ether vapor at room temperature under ambient for three weeks. Blocklike dark-red crystals were formed and collected by filtration and dried in air (yield 0.202 g, 46 %). DiscussionIron complexes play an important role in biological field, catalysis application and earth chemistry research [1-4]. Schiff base complexes containing different central metal atoms such as Zn, Cu, Ni and Ru have been studied in great detail for their various crystallographic features, enzymatic reactions and magnetic properties [5][6][7]. To the best of our knowledge, the iron(ni) salicylaldehyde Schiff base complexes have been seldom reported [8,9]. At the same time, the study of octahedron complexes involving an aromatic Schiff base as the primary ligand, isothiocyanato ion as secondary ligand can serve as a useful model for gaining a better understanding of enzyme-metal ion-substrate complexes, which plays an important role in metalloenzyme-catalyzed biochemical reactions. Based on the studies of the iron complexes and the salicylaldehyde Schiff base, in the present ferrum enzyme mutational investigation, an octahedral complex of iron(m) ion with sal-en Schiff base as ligand has been template synthesized and characterized. The asymmetric unit of the crystal structure consists of a discrete [Fe(sal-en)2] + cation and a counter isothiocyanato anion (figure, top). The central ϊτοη(ΙΠ) ion is six-coordinated (FeN4C>2) and the coordination polyhedron can be described as an distorted octahedron formed by the four nitrogen atoms of the ethylenediamine molecule part, and two hydroxyl oxygen atoms from salicylaldehyde molecule part. In the complex, the salicylaldehyde-ethylenediamine Schiff base molecule acts as tridentate chelate ligand, obviously, only one of the amidocyanogen group of the ethylenediamine was involved in the reaction to salicylaldehyde to obtain the sal-en Schiff base during the template synthesis. Nl, N3,02, N2 are occupied at equatorial positions, Ol, N4, are occupied at apical positions, Fel, Nl, N2, C8, N9 form a cyclopental ring, and Fei, Ol, Nl, N2, CI, C2 form a cyclohexal ring. All the atoms of two six-membered rings are almost at the Brought to you by | HEC Bibliotheque Maryriam ET J. Authenticated Download Date | 8/3/15 2:52 PM