C19H22FeN5O2S, triclinic, P1 (no. 2), a = 9.613(1) Å, b = 9.913(1) Å, c = 10.869(2) Å, a = 84.958(2)°, b = 89.047(2)°, g = 86.098(1)°, V = 1029.3 Å 3 , Z = 2, Rgt(F) = 0.038, wRref(F 2 ) = 0.099, T = 291 K. Source of materialThe mixture of FeCl 2 · 4H 2 O (0.122 g, 0.5 mmol) and NH 4 SCN (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][2][3][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(III) 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 imitational investigation, an octahedral complex of iron(III) 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 iron(III) ion is six-coordinated (FeN4O2 ) 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. N1, N3, O2, N2 are occupied at equatorial positions, O1, N4, are occupied at apical positions, Fe1, N1, N2, C8, N9 form a cyclopental ring, and Fe1, O1, N1, N2, C1, C2 form a cyclohexal ring. All the atoms of two six-membered rings are almost at the

Source of materialThe mixture of Pb(CH 3 COO) 2 · 3H 2 O (2 mmol) and 1,10-phenanthroline (2 mmol) was stirred into 10 mL aqueous solution at room temperature. Then the pH was adjusted to approximately 6 with 3 M NaOH. The reaction mixture was heated on a water bath, holding for 3 h at 65°C, and then filtered. The colorless crystal was separated from the mother liquor by slow evaporation at room temperature after 18 days (yield 0.36 g, 46 %). DiscussionAs a toxic heavy metal element in biological systems and natural environment, the construction of Pb(II) organic coordination frameworks by metal coordination directed self-assembly processes has attracted extensive attention in recent years [1][2][3][4]. Pb(II) ions cannot only form coordination polymers and polynuclear complexes, but also frequently were discussed in regard to the possible stereochemical activity of the valence shell lone electron pairs [5][6][7]. This metal ion adapts to different coordinations as a consequence of the large ionic radius and adopts different coordination numbers. On the other hand, aromatic rings and carboxyl groups are important structural and functional elements in synthetic supramolecular architectures. They significantly devote to the intramolecular stabilization of structures and to the formation of intermolecular complexes. Moreover, hydrogen bonds also play vital roles in creating high-dimensional structure and stabilizing metal-organic coordination frameworks. Taking the aspects mentioned above into account, we investigate herein a new coordination polymer of lead(II) with 1,10-phenanthroline and acetate ligands. Although the coordination structures of Pb(II) ion with 1,10-phenanthroline and acetate ligands have been reported [8,9], such coordination mode of four acetatebridged polymeric lead(II) complex [Pb(phen)(CH 3COO)2]n has not been described yet.In the crystal structure of the complex, each Pb(II) ion is sixcoordinated by four oxygen atoms (the bond lengths of PbO1 and PbO2 are 2.9614(4) Å and 2.652(4) Å, respectively) from four acetate ligands and two nitrogen atoms (the bond length of PbN1 is 2.554(4) Å) from one bidentate phen ligand to generate a N 2O4 distorted octahedral environment (figure, top etate ligands act as bridge three Pb(II) ions and form two eightmembered rings which display a twisted non-coplanar coordination mode. Each acetate adopts the bis-monodentate coordination mode to link two adjacent Pb(II) ions forming one-dimensional chain (figure, middle). The phen ligands are alternately attached to both sides of the chain. The bond angles of N1Pb1O2 and O2CPb1O2 are 143.4(2)°and 135.7(2)°, respectively. The arrangement of the phen and acetate ligands suggests a gap coordination around the Pb(II) ion, which might be occupied by a stereoactive lone pair of electrons on Pb(II) ion and also probably due to steric hindrance of the phen and acetate ligands. It is noteworthy that there exist weak hydrogen bond interactions between the neighboring one-dimensional chains. This is the other remarkably differ...