Crystal structure of dibromo(N-ethyl-N'-pyridinylmethyleneethane-1,2- diamino)zinc(II), ZnBr2(C10H15N3)

Abstract

Source of materialAll the chemicals used were of AR grade. N-ethyl-1,2-diaminoethane (8.8 mg, 0.1 mmol) and pyridine-2-carbaldehyde (10.8 mg, 0.1 mmol) were refluxed in 10 ml methanol for 30 min. To the above solution was added ZnBr 2 (23.0 mg, 0.1 mmol) in 10 ml methanol. The mixture was refluxed for 1 h. The mixture was filtered after cooling to room temperature. After keeping the filtrate in air for 10 d, colorless crystals were formed. DiscussionZinc is the second most abundant transition or post-transition metal in biology. It functions as the active site of hydrolytic enzymes, such as carboxypeptidase and carbonic anhydrase, where it is in a hard-donor coordination environment of nitrogen and oxygen [1]. It also has long been recognized as an important cofactor in biological molecules, either as a structural template in protein folding or as a Lewis acid catalyst that can readily adopt four-, fiveor six-fold coordination [2-6]. Recent reports have suggested that zinc is able to play a catalytic role in the activation of thiols as nucleophiles at physiological pH [7,8]. We have reported the structure of a mononuclear Schiff base zinc(II) complex [9] and synthesized a further Schiff base zinc(II) complex and determined its crystal structure.In the title complex, the Zn(II) atom is coordinated by the pyridine N, imine N and amine N atoms of the Schiff base ligand and by two bromide anions, forming a distorted trigonal bipyramidal environment. The ZnN and ZnBr bond lengths are comparable to the values in other similar complexes [10][11][12]. The bond angles subtended at the Zn atom at the basal plane range from 112.35(9)°t o 131.66(9)°, and the bond angle of N1Zn1N3 at the axial positions deviates from the ideal value of 180°by 29.5(1)°, indicating a distorted trigonal bipyramid coordination. The deviation of ÐN1Zn1N3 is result from the steric effects of the five-membered chelate rings Zn1/N1/C2/C1/N2 and Zn1/N2/C7/C8/N3. Atom N8 deviates from the plane defined by Zn1/N2/C7/N3 by 0.644(6) Å.

Synthesis and Crystal Structures of Zinc(II) Complexes with Schiff Bases Derived from 2-Acetylpyridine

“…The coordinate bond lengths in the complexes are comparable to each other, and also comparable with those observed in other similar zinc(II) complexes with Schiff bases. [18][19][20] In the crystal structure of (1), molecules are linked through intermolecular N-H···N, C-H···N, and C-H···Br hydrogen bonds, forming a 3D network (Figure 4). In the crystal structure of (2), the adjacent molecules are linked through two intermolecular C-H···I hydrogen bonds, forming a dimer ( Figure 5).…”

3-Hydroxy-N′-(2-hydroxybenzylidene)benzohydrazide

“…For related literature, see: Ali et al (2005); Eltayeb et al (2008); Habibi et al (2007); Jing et al (2006); Ling et al (2008); Peng & You (2007); Peng & Zhou (2007); Peng, Ping & Song (2007); ; ; Yehye et al (2008a,b).…”