Bis{2-methoxy-6-[3-(methylamino)propyliminomethyl]phenolato}nickel(II) bis(perchlorate)

The asymmetric unit of the title compound, [Ni(C12H18N2O2)2](ClO4)2, consists of one-half of a centrosymmetric mononuclear Schiff base nickel(II) complex cation and one perchlorate anion. The NiII ion, lying on the inversion center, is coordinated by two N atoms and two O atoms from two Schiff base ligands, forming a square-planar geometry. The crystal packing is stabilized by N—H⋯O hydrogen bonds.

The asymmetric unit of the title compound, [Ni(C 12 H 18 -N 2 O 2 ) 2 ](ClO 4 ) 2 , consists of one-half of a centrosymmetric mononuclear Schiff base nickel(II) complex cation and one perchlorate anion. The Ni II ion, lying on the inversion center, is coordinated by two N atoms and two O atoms from two Schiff base ligands, forming a square-planar geometry. The crystal packing is stabilized by N-HÁ Á ÁO hydrogen bonds.
However, the complexes derived from the Schiff base ligand 2-methoxy-6-[(3-methylaminopropylimino)methyl]phenol have never been reported. The author reports herein the title mononuclear nickel(II) complex.
The title compound consists of a centrosymmetric nickel(II) complex cation and two perchlorate anions (Fig. 1). The Ni II ion, lying on the inversion center, is coordinated by two nitrogen atoms and two oxygen atoms from two Schiff base ligands, giving a square planar geometry. All the bond lengths and angles (Table 1) involving the Ni II atom are within normal ranges, and comparable to values observed in other Schiff base nickel(II) complexes (Zhu et al., 2004;Zhao, 2007;Bian et al., 2004;Skovsgaard et al., 2005). The N1-C8-C9-C10 and C9-C10-N2-C11 torsion angles are 55.0 (3) and 2.7 (3)°, respectively. The crystal packing is stabilized by N-H···O hydrogen bonds (Table 2).

S2. Experimental
N-Methylpropane-1,3-diamine (0.5 mmol, 44.0 mg) and 3-methoxysalicylaldehyde (0.5 mmol, 76.0 mg) were dissolved in methanol (30 ml). The mixture was stirred for 1 h to obtain a clear yellow solution. To the solution was added with stirring a methanol solution (20 ml) of nickel(II) perchlorate (0.5 mmol, 192.0 mg). After keeping the resulting solution in air for a few days, red block-shaped crystals were formed.

S3. Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H = 0.93-0.97 Å, N-H = 0.90 Å, and with U iso (H) = 1.2U eq (C,N) and 1.5U eq (methyl C).  The molecular structure of the title compound, showing 30% probability displacement ellipsoids. Unlabelled atoms are related to labelled atoms by the symmetry operation (1 -x, 1 -y, 1 -z).

Bis{2-methoxy-6-[3-(methylamino)propyliminomethyl]phenolato}nickel(II) bis(perchlorate)
Crystal data [Ni(C 12  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.97 e Å −3 Δρ min = −0.55 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0023 (6) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq