Crystal structure of aqua-((E)-N-(2-(2-hydroxybenzylideneamino)ethyl)- 4-methylbenzenesulfonamide)-copper(II), Cu(H2O)(C16H17N2O3S)

Abstract

Source of materialThe sulfonamide Schiff base ligand (E)-N-(2-(2-hydroxybenzylideneamino)ethyl)-4-methylbenzenesulfonamide (L) was synthesized by reacting tosyl-ethylenediamine with one equivalent of salicylaldehyde in ethanol. It is formed as yellow crystals (m.p. 126-127°C). To 20 mL hot ethanol solution containing 0.214 g (1 mmol) L, 0.199 g Cu(CH3COO)2 · H2O (1 mmol) in 10 mL ethanol was added under stirring for 1 h. A dark green solution was formed and filtrated. The filtrate was left for slow evaporation. Dark green block-shaped crystals of the title compound were obtained after 2 weeks. Experimental detailsThe H atoms were located in difference maps. While the water H atom positions were refined, the other H atoms were fixed in idealized positions and refined as riding with Uiso(H) = 1.2U eq or 1.5Ueq. DiscussionIn the title crystal structure copper(II) atom is chelated by one unsymmetrical Schiff base ligand providing their amide, amine N atoms and phenolate O atom and one water molecule (figure, top). A distorted square planar CuN2O2 environment arises with the N1···N2 and O1···O4 distances (2.605 Å and 2.662 Å, respectively) shorter than the N1···O1 and N2···O4 distances (2.801 Å and 2.902 Å, respectively). The Cu1N1 distance (1.923 Å) is shorter than Cu1N2 (1.969 Å) suggesting that the imine nitrogen atom is a slightly better donor than amide nitrogen atom because the electron density is delocalized into the sulfonyl group. The Cu1O4(water) distance is longer than Cu1O1(phenolate). The four coordinated atoms (N2O2) are arranged in a cisconformation. In the molecule, the chelated five-membered ring (Cu1-N1-C8-C9-N2) and six-membered ring (Cu1-O1-C2-C1-C7-N1) also contribute to the stability of the complex. The bondvalence sum for the Cu center is calculated to be 2.2, which is close to the expected value of 2 [1]. A strong intramolecular OH···O hydrogen bond helps to stabilize the molecular conformation (O4H4B···O2 with 0.66(7) Å, 2.02(7) Å, 2.603(3) Å, 149(8)°). The resulting six-membered chelate ring (Cu1-N2-S1-O2···H4B-O4) is planar with a mean deviation of 0.0830 Å. The crystal packing may be further stabilized by CH···O, CH···p and p···p interactions (figure, middle). The resulting C12H12···O3 hydrogen bonds among different symmetric motifs link the structure in layers running parallel to the a axis and shows a centrosymmetric arrangement mode. In the structure, there are the two p···p interactions formed between two rings of one molecule and its symmetry equivalent by inversion (x,y,z). The Cg···Cg i distance is 3.515 Å, where Cg and Cg i are the centroids of ring 1 (Cu1-O1-C2-C1-C7-N1) and ring 2 (C10 Z. Kristallogr.