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Acta Cryst. (2007). E63, m1820    [ doi:10.1107/S1600536807026852 ]

Tetrakis(pyrazine-[kappa]N)bis(thiocyanato-[kappa]N)manganese(II)

T. Liu and Z.-P. Xie

Abstract top

In the molecule of the title complex, [Mn(NCS)2(C4H4N2)4], the MnII atom is coordinated in a distorted octahedral arrangement by two N atoms of two SCN- and four N atoms of four pyrazine ligands. A crystallographic twofold rotation axis passes through the Mn atom, and the N and para-N atoms of two trans pyrazine rings. In the crystal structure, the non-classical hydrogen bonds and the weak [pi]-[pi] stacking interactions, involving the pyrazine rings of adjacent pyrazine ligands with a centroid-centroid distance of 3.3205 (4) Å, contribute to the formation of a supramolecular network structure.

Comment top

There are three manganese enzymes containing a mononuclear manganese site, viz. superoxide dismutase, peroxidase and dioxygenase, which participate in redox changes in the respective areas of biology (Law et al., 1999). Carboxylatobridged complexes, such as pyridine, phenanthroline, quinoline and benzimidazole, are often employed to mimic the function and structure of these active sites, based on the knowledge that Mn centres in these enzymes are predominately coordinated by N,O donors from available amino acid side chains (Pecoraro & Butler, 1986; Wu et al., 2003; Pan & Xu, 2004; Liu et al., 2004; Li et al., 2005). We herein report the crystal structure of the title compound, (I).

In the molecule of (I), (Fig. 1) the ligand bond lengths and angles are within normal ranges (Allen et al., 1987). The two N atoms of two SCN- and four N atoms of four pyrazine ligands are coordinated to the Mn atom, in a distorted octahedral arrangement (Table 1). A crystallographic twofold rotation axis passes through the Mn atom, and the N and para-N atoms of two trans pyrazine rings. The planar pyrazine rings I (N3/N6/C4—C7), II (N2/N7/C2A/C3A/C2—C3) and III (N4/N5/C8A/C9A/C8—C9) are nearly perpendicular to each other, with dihedral angles of I/II = 87.7 (2), I/III = 109.2 (6) and II/III = 85.9 (7)°.

In the crystal structure, the non-classical hydrogen bonds and the weak π-π stacking interactions, involving the pyrazine rings of adjacent pyrazine ligands with centroid-centroid distance of 3.3205 (4) Å [symmetry code: 1 - x, 2 - y, 1 - z], cause to the formation of a supramolecular network structure (Fig. 2).

Related literature top

For related literature, see: Allen et al. (1987); Law et al. (1999); Li et al. (2005); Liu et al. (2004); Pan & Xu (2004); Pecoraro & Butler (1986); Wu et al. (2003).

Experimental top

Crystals of the title compound were synthesized using hydrothermal method in a Teflon-lined Parr bomb (23 ml), which was then sealed. Manganese(II) chloride tetrahydrate (39.6 mg, 0.2 mmol), potassium thiocyanate (38.9 mg, 0.4 mmol), pyrazine (1.5 ml), and distilled water (2 g) were placed into the bomb and sealed. The bomb was heated under autogenous pressure for 6 d at 413 K and allowed to cool at room temperature for 24 h. Upon opening the bomb, a clear colourless solution was decanted from small yellow crystals. These crystals were washed with distilled water followed by ethanol, and allowed to air-dry at room temperature.

Refinement top

H atoms were positioned geometrically, with C—H = 0.93 Å for aromatic H and constrained to ride on their parent atoms, with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry code (A): - x, y, 3/2 - z].
[Figure 2] Fig. 2. A packing diagram for (I).
Tetrakis(pyrazine-κN)bis(thiocyanato-κN)manganese(II) top
Crystal data top
[Mn(NCS)2(C4H4N2)4]F(000) = 1004
Mr = 491.47Dx = 1.308 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2231 reflections
a = 11.425 (5) Åθ = 2.3–23.8°
b = 14.543 (4) ŵ = 0.72 mm−1
c = 15.022 (3) ÅT = 273 K
β = 90.759 (5)°Block, yellow
V = 2495.7 (15) Å30.26 × 0.16 × 0.07 mm
Z = 4
Data collection top
Bruker APEXII area-detector
diffractometer		2434 independent reflections
Radiation source: fine-focus sealed tube1675 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
φ and ω scansθmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −14→13
Tmin = 0.836, Tmax = 0.952k = −17→17
7912 measured reflectionsl = −18→18
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.159 w = 1/[σ2(Fo2) + (0.1074P)2 + 0.9725P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
2434 reflectionsΔρmax = 0.52 e Å−3
144 parametersΔρmin = −0.39 e Å−3
0 restraintsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0113 (16)
Crystal data top
[Mn(NCS)2(C4H4N2)4]V = 2495.7 (15) Å3
Mr = 491.47Z = 4
Monoclinic, C2/cMo Kα radiation
a = 11.425 (5) ŵ = 0.72 mm−1
b = 14.543 (4) ÅT = 273 K
c = 15.022 (3) Å0.26 × 0.16 × 0.07 mm
β = 90.759 (5)°
Data collection top
Bruker APEXII area-detector
diffractometer		2434 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		1675 reflections with I > 2σ(I)
Tmin = 0.836, Tmax = 0.952Rint = 0.033
7912 measured reflectionsθmax = 26.0°
Refinement top
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.159Δρmax = 0.52 e Å−3
S = 1.09Δρmin = −0.39 e Å−3
2434 reflectionsAbsolute structure: ?
144 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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 (Å2) top
xyzUiso*/Ueq
Mn10.00000.35963 (4)0.75000.0486 (3)
S1−0.36253 (15)0.36697 (11)0.93412 (13)0.1233 (6)
N1−0.1575 (3)0.3629 (2)0.8242 (3)0.0787 (10)
N20.00000.2153 (3)0.75000.0686 (11)
N30.1076 (3)0.3603 (2)0.8756 (2)0.0694 (8)
N40.00000.5066 (3)0.75000.0700 (11)
N50.00000.6957 (5)0.75000.150 (3)
N60.2516 (6)0.3887 (4)1.0292 (5)0.142 (2)
N70.00000.0280 (5)0.75000.131 (2)
C1−0.2437 (3)0.3646 (2)0.8699 (3)0.0663 (10)
C2−0.0418 (4)0.1680 (3)0.8208 (3)0.0785 (11)
H2−0.07060.20070.86910.094*
C3−0.0430 (5)0.0761 (3)0.8235 (3)0.0957 (14)
H3−0.07160.04490.87270.115*
C40.2251 (4)0.3423 (3)0.8760 (3)0.0892 (13)
H40.25720.32050.82340.107*
C50.3009 (5)0.3539 (4)0.9491 (5)0.1116 (19)
H50.38010.33960.94560.134*
C60.1327 (7)0.4051 (5)1.0275 (4)0.140 (3)
H60.09740.42671.07880.168*
C70.0637 (5)0.3904 (4)0.9517 (3)0.1084 (17)
H7−0.01620.40220.95450.130*
C80.0981 (4)0.5541 (3)0.7764 (3)0.0853 (12)
H80.16520.52140.79230.102*
C90.1006 (5)0.6463 (3)0.7802 (5)0.112 (2)
H90.16630.67710.80200.134*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mn10.0436 (5)0.0510 (5)0.0515 (5)0.0000.0112 (3)0.000
S10.0995 (11)0.1354 (13)0.1366 (14)0.0019 (8)0.0649 (10)0.0009 (9)
N10.071 (2)0.086 (3)0.079 (2)0.0017 (16)0.0187 (17)−0.0001 (17)
N20.074 (3)0.065 (3)0.067 (3)0.0000.005 (2)0.000
N30.068 (2)0.0669 (19)0.074 (2)0.0020 (15)0.0040 (15)−0.0021 (15)
N40.064 (3)0.063 (3)0.084 (3)0.0000.004 (2)0.000
N50.142 (7)0.086 (5)0.220 (9)0.000−0.020 (6)0.000
N60.148 (5)0.141 (4)0.134 (5)0.002 (4)−0.031 (4)−0.020 (4)
N70.165 (7)0.088 (4)0.140 (6)0.000−0.015 (5)0.000
C10.064 (2)0.065 (2)0.070 (2)0.0039 (17)0.0125 (17)−0.0001 (17)
C20.087 (3)0.070 (2)0.078 (3)−0.006 (2)0.005 (2)0.009 (2)
C30.127 (4)0.071 (3)0.089 (3)−0.007 (3)0.001 (3)0.008 (2)
C40.071 (3)0.107 (4)0.090 (3)0.012 (2)0.001 (2)0.015 (2)
C50.076 (3)0.130 (5)0.127 (5)−0.001 (3)−0.019 (3)0.026 (4)
C60.129 (5)0.188 (7)0.101 (4)0.048 (5)−0.033 (4)−0.042 (4)
C70.094 (3)0.154 (5)0.078 (3)0.028 (3)−0.008 (2)−0.031 (3)
C80.074 (3)0.071 (3)0.111 (3)−0.009 (2)−0.003 (2)0.005 (2)
C90.094 (4)0.070 (3)0.171 (6)−0.010 (3)−0.025 (4)0.000 (3)
Geometric parameters (Å, º) top
Mn1—N12.130 (4)N6—C61.378 (8)
Mn1—N22.100 (4)N6—C51.428 (9)
Mn1—N32.239 (3)N7—C3i1.401 (6)
Mn1—N42.137 (4)N7—C31.401 (6)
Mn1—N1i2.130 (4)C2—C31.338 (6)
Mn1—N3i2.239 (3)C2—H20.9300
S1—C11.676 (4)C3—H30.9300
N1—C11.209 (6)C4—C51.400 (7)
N2—C2i1.359 (5)C4—H40.9300
N2—C21.359 (5)C5—H50.9300
N3—C71.328 (6)C6—C71.393 (7)
N3—C41.368 (5)C6—H60.9300
N4—C81.371 (5)C7—H70.9300
N4—C8i1.371 (5)C8—C91.342 (6)
N5—C91.424 (6)C8—H80.9300
N5—C9i1.424 (6)C9—H90.9300
N1—Mn1—N291.29 (9)C3i—N7—C3120.2 (6)
N1—Mn1—N390.98 (14)N1—C1—S1179.5 (4)
N1—Mn1—N488.71 (9)C3—C2—N2122.2 (4)
N2—Mn1—N390.26 (8)C3—C2—H2118.9
N2—Mn1—N4180.000 (1)N2—C2—H2118.9
N3—Mn1—N489.74 (8)C2—C3—N7118.1 (5)
N2—Mn1—N1i91.29 (9)C2—C3—H3121.0
N1i—Mn1—N1177.42 (19)N7—C3—H3121.0
N1i—Mn1—N488.71 (9)N3—C4—C5125.2 (5)
N1i—Mn1—N389.01 (14)N3—C4—H4117.4
N2—Mn1—N3i90.26 (8)C5—C4—H4117.4
N1i—Mn1—N3i90.98 (14)C4—C5—N6117.2 (5)
N1—Mn1—N3i89.01 (14)C4—C5—H5121.4
N4—Mn1—N3i89.74 (8)N6—C5—H5121.4
N3—Mn1—N3i179.48 (15)N6—C6—C7122.4 (6)
C1—N1—Mn1176.9 (4)N6—C6—H6118.8
C2i—N2—C2119.2 (5)C7—C6—H6118.8
C2i—N2—Mn1120.4 (3)N3—C7—C6122.5 (5)
C2—N2—Mn1120.4 (3)N3—C7—H7118.8
C7—N3—C4116.3 (4)C6—C7—H7118.8
C7—N3—Mn1121.1 (3)C9—C8—N4122.2 (5)
C4—N3—Mn1122.0 (3)C9—C8—H8118.9
C8—N4—C8i119.4 (5)N4—C8—H8118.9
C8—N4—Mn1120.3 (2)C8—C9—N5118.3 (5)
C8i—N4—Mn1120.3 (2)C8—C9—H9120.9
C9—N5—C9i119.4 (6)N5—C9—H9120.9
C6—N6—C5116.5 (5)
Symmetry code: (i) −x, y, −z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···N1i0.932.553.109 (6)119
C7—H7···N10.932.583.176 (6)122
Symmetry code: (i) −x, y, −z+3/2.
Selected geometric parameters (Å, º) top
Mn1—N12.130 (4)Mn1—N32.239 (3)
Mn1—N22.100 (4)Mn1—N42.137 (4)
N1—Mn1—N291.29 (9)N2—Mn1—N390.26 (8)
N1—Mn1—N390.98 (14)N2—Mn1—N4180.000 (1)
N1—Mn1—N488.71 (9)N3—Mn1—N489.74 (8)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···N1i0.932.553.109 (6)119
C7—H7···N10.932.583.176 (6)122
Symmetry code: (i) −x, y, −z+3/2.
Acknowledgements top

Any acknowledgements?

references
References top

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