trans-{1,8-Bis[(R)-α-methylbenzyl]-1,3,6,8,10,13-hexaazacyclotetradecane}dithiocyanatonickel(II)

The title compound, [Ni(NCS)2(C24H38N6)], is a thiocyanate-coordinated azamacrocyclic nickel(II) complex. There are two independent molecules in the asymmetric unit and their bond lengths and angles are similar. Both Ni atoms have a tetragonally distorted octahedral geometry, in which the NiII ion is coordinated by the four secondary N atoms of the azamacrocyclic ligand and by two N atoms of the thiocyanate ions. The average equatorial Ni—N bond lengths are shorter than the average axial Ni—N bond lengths [2.071 (1) and 2.115 (2) Å, respectively]. N—H⋯S hydrogen-bonding interactions between a secondary amine N atom and the adjacent thiocyanate ion leads to a polymeric chain along [100].

The title compound, [Ni(NCS) 2 (C 24 H 38 N 6 )], is a thiocyanatecoordinated azamacrocyclic nickel(II) complex. There are two independent molecules in the asymmetric unit and their bond lengths and angles are similar. Both Ni atoms have a tetragonally distorted octahedral geometry, in which the Ni II ion is coordinated by the four secondary N atoms of the azamacrocyclic ligand and by two N atoms of the thiocyanate ions. The average equatorial Ni-N bond lengths are shorter than the average axial Ni-N bond lengths [2.071 (1) and 2.115 (2) Å , respectively]. N-HÁ Á ÁS hydrogen-bonding interactions between a secondary amine N atom and the adjacent thiocyanate ion leads to a polymeric chain along [100].

trans-{1,8-Bis[(R)-α-methylbenzyl]-
In the title compound, the coordination geometry around the nickel(II) ion is a tetragonally distorted octahedron in which the nickel(II) ion is coordinated to the four secondary N atoms of the azamacrocyclic ligand in a square-planar fashion and two N atoms from the thiocyanate ions at the axial positions as shown in Figure 1. The average Ni-N eq and Ni-N ax bond distances are 2.071 (1) and 2.115 (2) Å, respectively. The former is slightly less than the latter, which can be attributed to the Jahn-Teller distortion of the nickel(II) ion and/or the ring contraction of the azamacrocyclic ligand. In the coordinated thiocyanate ions, the average N-C and C-S bond distances are 1.166 (3) and 1.621 (3) Å, respectively.
The former is very similar to a CN triple bond length, while the latter is slightly shorter than the normal CS single bond distance (Stølevik & Postmyr, 1997;Banerjee & Zubieta, 2004). The pendant arms of the azamacrocyclic ligand have chiral carbon atoms (R type). All thiocyanate ions binding nickel(II) ions axially are involved in N-H···S hydrogen bonding interactions (Table 1), which give rise to one-dimensional polymeric chains propagating along the a axis ( Figure   2). The shortest Ni···Ni intrachain separation within the hydrogen-bonded one-dimensional polymer is 8.531 (1) Å and is about 5% longer than the shortest interchain Ni···Ni distance of 8.166 (1) Å.

S2. Experimental
The title compound is prepared as follows: To an MeCN solution (10 ml) of [Ni(C 24 H 38 N 6 )](ClO 4 ) 2 (0.10 g, 0.15 mmol) (Han et al., 2008) was added dropwise an aqueous solution (10 ml) containing NaSCN (0.024 g, 0.30 mmol) at ambient temperature. The color of the solution changed from yellow to pale pink. The mixture was stirred for 30 min during which time a pink precipitate formed which was collected by filtration, washed with MeCN and water, and dried in air.
Single crystals of the title compound suitable for X-ray crystallography were grown by layering of the MeCN solution of [Ni(C 24 H 38 N 6 )](ClO 4 ) 2 on the aqueous solution of NaSCN within one week. and with U iso (H) values of 1.2 times the equivalent anisotropic displacement parameters of the parent C and N atoms.

Figure 1
ORTEP drawing of the molecular title compound with atomic numbering scheme and ellipsoids at 40% probability.

Figure 2
Perspective view of the title compound showing a one-dimensional chain formed by N-H···S hydrogen bonding interactions.

Crystal data
[Ni(NCS) 2 (C 24 H 38 N 6 )] M r = 585.47 Orthorhombic, P2 1 2 1 2 1 Hall symbol: P 2ac 2ab a = 8.5313 (5) where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.81 e Å −3 Δρ min = −0.93 e Å −3 Absolute structure: Flack (1983) Absolute structure parameter: −0.004 (17) 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.