Trans-bis(3-tert-butylpyridine-κN)bis(4-tert-butylpyridine-κN)bis(thiocyanato-κN)manganese(II)

The asymmetric unit of the title compound [Mn(NCS)2(C9H13N)4] consists of one MnII cation located on a center of inversion, one thiocyanato anion, one 3-tert-butylpyridine ligand and one 4-tert-butylpyridine ligand in general positions. The tert-butyl group of the 4-tert-butylpyridine ligand is disordered over two sets of sites in a 0.60:0.40 ratio. The MnII cation is coordinated by six N atoms of four tert-butylpyridine ligands and two N-bonded thiocyanato anions within a slightly distorted octahedral coordination environment.


Thorben Reinert, Inke Jess and Christian Näther Comment
The structure determination of the title compound was performed as part of a project on the synthesis of new coordination polymers based on transition metal thiocyanates and the investigations of their magnetic behaviour (Boeckmann et al., 2010;Boeckmann et al., 2011). Within this project we have reacted manganese(II)thiocyanate monohydrate with 4-tert-butylpyridine in water, which resulted in the formation of crystals of the title compound by accident. Apparently, the 4-tert-butylpyridine was contaminated with 3-tert-butylpyridine to a degree that allowed the formation of a few single crystals of the title compound. It was on the other hand not possible to obtain phase pure crystalline powder samples. In the crystal structure Mn atoms are surrounded by six N atoms of four tert-butylpyridine ligands and two N-bonded thiocyanato anions in mutual trans orientation in a slightly distorted octahedral geometry ( Fig.   1). Mn···N distances range from 2.180 (3) Å to 2.337 (2) Å. It is also worth mentioning that so far no other compound containing 3-tert-butylpyridine has been reported in the CSD.

Experimental
The title compound was obtained accidently during the reaction of 28.4 mg Mn(NCS) 2 × H 2 O (0.15 mmol) with 44.4 µL 4-tert-butylpyridine (0.30 mmol), obtained from Sigma Aldrich, in 1.50 ml water at RT in a closed 3 mL snap cap vial.
After three weeks colourless needles of the title compound were obtained.

Refinement
H atoms were positioned with idealized geometry and were refined isotropically with U iso (H) = 1.2 U eq (C) (1.5 for methyl H atoms) of the parent atom using a riding model with C-H = 0.95 Å for aromatic and 0.98 Å for methyl hydrogen atoms. The tert-butyl group of the 4-tert-butylpyridine ligand is disordered and was refined using a split model with fixed site occupation factors of 0.60 and 0.40. Distances between the methyl groups in the two disordered moieties were restrained to be equal.  Molecular structure of the title compund with displacement ellipsoids drawn at the 50% probability level (symmetry code: i = -x + 1, -y + 1, -z + 2). Disorder is shown as full and open bonds.

Trans-bis(3-tert-butylpyridine-κN)bis(4-tert-butylpyridine-κN)bis(thiocyanato-κN)manganese(II)
Crystal data [Mn(NCS) 2 (C 9 H 13 N) 4 ] M r = 711.92 Triclinic, P1 Hall symbol: -P 1 a = 9.5921 (7) Å b = 10.7253 (9) Å c = 11.6286 (10) 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 Occ. (