Crystal structure of bis[1-(2-hydroxybenzylidene)thiosemicarbazido]- nickel(II) dinitrate, [Ni(C8H9N3OS)2](NO3)2

Abstract

C16H18N8NiO8S2, monoclinic, C12/c1 (no. 15), a = 17.964(2) A, b = 9.834(1) A, c = 14.122(2) A, ) = 110.582(1)°, V = 2335.7 A, Z = 4, Rgt(F) = 0.028, wRref(F ) = 0.070, T = 296 K. Source of material A methanol solution (20 mL) of 3-thiosemicarbazide (0.073 g, 8.0 mmol) was added gradually to the methanol solution (10 mL) of salicylaldelyde (0.197 g, 16 mmol) with stirring. The reaction mixture was heated at 60 °C for 2 h. Then an ethanol solution of Ni(NO3)2.·.6H2O (1.16 g, 4.0 mmol) was added dropwise to the above solution, the resultant mixture was stirred 2 h, then cooled, and filtrated. The resulting clear solution was diffused with diethyl ether vapor at room temperature for two weeks to obtaine blue block-shaped crystals of the title complex suitable for X-ray crystal determination (yield 0.822 g, 36%).Chemical analysis— found: C, 34. 02 %; H, 3.09 %; N, 19.51 %; calculated for C16H18NiN8O8S2: C, 33.53%;H, 3.17%;N, 19.55%. IR data are available in the CIF. Discussion During past decades, the design and syntheses of Schiff base complexes has been extensively investigated due to their inherent coordination functionalities, spectroscopic characteristics, optical properties as well as biological and catalytic activities [1-4]. These complexes can serve as potent antitumor, antiviral and antibacterial agents [5]. Among these Schiff-base complexes, nickel(II) representatives have attracted great attention since nickel has been recognized as a considerably important biological agent forming the active site of a variety of metalloproteins, such as hygrogenase(H2-ase), carbon monoxide dehydrogenase (CODH), S-methyl-coenzyme-M methylreductase (MCR) and urease [6-8]. In addition, their adducts with nitrogen have potential applications in area of organic conductors andmagneticmaterials [9]. The asymmetric unit in the title complex contains a discrete mononuclear cation [Ni(HBTC)2] and two nitrate groups (figure, top). Each salicylaldehyde thiosemicarbazide Schiff base provides O, N, S as donor atoms, acting as a tridentate ligand. Two HBTC ligands chelate the central Ni(II) ion. The coordination polyhedron around Ni(II) ion can be considered as a slightly distored octahedron (NiO2N2S2). The equatorial plane is comprised of two oxygen atoms and two sulfur atomswhile two nitrogen atoms occupy the axial positions with N1–Ni1–N1A bond angle of 176.72(9)°. The chelation of each HBTC ligand with nickle ion form a five-membered ring Ni1–C8–N1–N2–S1 and one six-membered ring Ni1–C1–C6–C7–N1–O1 with dihedral angle of 21.27°. The bond lengths Ni—N, Ni—O, and Ni—S are 2.030(2) A, 2.118(1) A, and 2.3779(6) A, respectively, being comparable to those observed in Ni(II) complexes containing a S–C–N–N unit [10]. Every nitrate ion is planar, and the plane is nearly perpendicular to the adjacent benzene ring of HBTC with dihedral angle of 89.779(3)°. All atoms of nitrate ions participate in the formation of hydrogen bonds. Five kinds of intermolecular hydrogen bonds are formed between phenol oxygen atoms and nitrate ions [O1–H1···N4, O1–H1···O4, O1–H1···O2; symmetry code i: –x,y,–z+1/2] or between HBTC N atoms and nitrate O atoms [N3–H3A···O2, N2–H2D···O3; symmetry code ii: –x+1/2,y+1/2,–z+1/2]. These hydrogen bonds interconnect [Ni(HBTC)2] units to a layered supramolecular network (figure, bottom).Along [001], such layers are parallel stacked and Z. Kristallogr. NCS 225 (2010) 79-80 / DOI 10.1524/ncrs.2010.0032 79 © by Oldenbourg Wissenschaftsverlag, Munchen