trans-Diaquabis(N,N,N′-trimethylethylenediamine)nickel(II) dichloride

The nickel(II) atom in the cation of the title salt has a slightly distorted octahedral coordination environment defined by two O and four N atoms.


data reports
In the title salt, the asymmetric unit is comprised of half of the cationic complex and a chloride ion with the Ni II atom of the cation situated about a twofold rotation axis (Fig. 1). The chelate ring (Fig. 2) is in a slight envelope conformation on C1 with puckering parameters Q2 = 0.476 (2) and '2 = 79.8 (2) . The six-coordinate Ni II atom of the cation is connected to four N atoms from two methyl-substituted ethelenediamine ligands and two water molecules in a slightly distorted octahedral environment, with the two substituted ethylenediamine ligands and two water molecules each coordinating trans to each other. The Ni-N bond lengths of 2.1906 (18) and 2.1245 (18) Å compare well to those of 2.120 (13) Å in the literature (Swink & Atoji, 1960); the Ni-O bond of 2.1189 (15) Å is the shortest of the metal-ligand bonds.
The crystal packing features O-HÁ Á ÁCl and N-HÁ Á ÁCl intermolecular interactions with the Cl À ions forming weak bifurcated hydrogen bonds with nearby water molecules and N-H interactions from the en moieties (Fig. 3

Synthesis and crystallization
N,N,N 0 -Trimethylethylenediamine (0.47 g, 0.0046 mol) was added to 10 ml of 95% vol ethanol in a round-bottom flask. To this solution, 0.32 g (0.0013 mol) of NiCl 2 Á6H 2 O were added. The reaction mixture became green in color. The reaction contents were then refluxed for 18 h. After the reaction time, the solvent was removed under reduced pressure. The product was then re-dissolved in acetonitrile and then the acetonitrile was removed under reduced pressure in order to determine the yield of the product. (0.41 g, 82%). Single crystals of the product were obtained by dissolving the product in acetonitrile and then allowing a diethyl ether vapor to slowly diffuse into the acetonitrile solution which contained the product. Analysis calculated for [C 10 H 32 N 4 NiO 2 ]Cl 2 : C: 32.46; H: 8.72; N: 15.14. Found: C: 32.29; H: 8.59; N: 14.96. UV-Visible data: (nm), (" (M À1 cm À1 ) (2.4 mM in MeCN) 390.00 (24); 228.00 (1600); 222.00 (1700).

Figure 2
The molecular structure of the asymmetric unit of [Ni(C 5 H 16 N 4 O 2 ] 2+ 2Cl À , showing the atom-labeling scheme with displacement ellipsoids drawn at the 50% probability level.

Figure 1
A view of [Ni(C 5 H 16 N 4 O 2 ] 2+ 2Cl À , showing its structure generated from two asymmetric units containing half of the cation complex and a chloride ion situated about a twofold rotation axis on the Ni II ion. The green dotted lines represent hydrogen bonds.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

Funding information
JRM acknowledges support from The Science Institute of the College of Arts and Sciences at Fairfield University for this work. Jerry P. Jasinski expresses thanks to the National Science Foundation Major Research Instrumentation Program (grant No. CHE-1039027) for funds to purchase an X-ray diffractometer. ANS and NRB acknowledge financial support from the Klimas Fund to support their summer research at Fairfield University.

trans-Diaquabis(N,N,N′-trimethylethylenediamine)nickel(II) dichloride
Crystal data where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.45 e Å −3 Δρ min = −0.28 e Å −3 Absolute structure: Classical Flack method (Flack, 1983) preferred over Parsons because s.u. lower Absolute structure parameter: 0.011 (14) data-2 IUCrData (2020). 5, x201182 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. All of the H atoms were placed in their calculated positions and then refined with lengths of 0.99 Å (CH); 0.98 Å (CH 3 ) using a riding model with U iso (H) = 1.2U eq (CH, NH) or 1.5U eq (CH 3 ) of the parent atom. The idealized methyl group was refined as a rotating group. O-bound H atoms were located from a difference Fourier map and were refined freely.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )