Refinement of the crystal structure of bis(N-n-butylsalicylaldiminato- k2N,O)nickel(II), Ni(C11H14NO)2

Abstract

Source of materialSalicylaldehyde( 244 mg,2m mol) and n-butylamine (146 mg, 2mmol) were dissolved in an aqueous ethanol solution (10 mL). The mixture was stirred at room temperature for 1htogive aclear yellow solution, which was added to amethanol solution (10 mL) of NiCl 2 × 7H 2 O(512 mg, 2mmol). The mixture was stirred for another 30 min at room temperature to give abrown solution and then filtered. The filtrate was kept in air for 7days, forming dark blue block-shaped crystals. The crystals were isolated and dried in avacuumdesiccatorcontaininganhydrous CaCl 2 (yield 62 %).All reagents and solvents were used as obtained without further purification. Elemental analysis -found: C, 64.00 %; H, 6.92 %; N, 6.61 %; calculated forC 22 H 28 N 2 NiO 2 :C,64.26 %; H, 6.86 %; N, 6.81 %. IR data are available in the CIF file. DiscussionAll Hatoms were placed in geometrically idealized positions and constrained to ride on their parent atomswith d(C-H) =0.93-0.97 Åand U iso (H) =1.2 U eq (carrier) or 1.5 U eq (methyl groups). DiscussionNickel is an important urease-required element. Due to their biologically relevant important behaviors, many nickel complexes with Schiff base have been extensively investigated in the past decades [1][2][3]. Forexample, the Schiff base nickel(II)complex with N,O-donor ligands possesses potent inhibitory activity against urease [4]. Due to their structural and electronic characteristics, bis(salicylaldiminato)nickel(II) complexes, possessing the substituents R and X on the imino and aromatic moieties, have been widely investigated since early 1960s [5,6].I nterestingly, these complexes mayd isplay different structural arrangements, whosestability strongly depends on thesterichindrance of the R groupb ound to thei mino moiety. For example, when R is the linear n-butyl group avery small distortion from planarity is observed [7]. In the title crystal structure with the n-butyl group bound to the imino moiety, the Schiffbase Ni(II) complex has inversion symmetry; Ni(II) lieso nt he center of symmetry (symmetry code: 1-x,2-y,-z)and is four-coordinated by two Natoms and two O atomsf rom two bidentate Schiff base ligands, which affords a square planar trans-