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Acta Cryst. (2012). E68, m1453-m1454    [ doi:10.1107/S1600536812044765 ]


H. Rinta, A. Peuronen and M. Lahtinen

Abstract top

The asymmetric unit of the title three-dimensional coordination polymer, [Mn2Br6(C11H28N2O2)]n, consists of one MnII cation, half of a dicationic N,N'-bis­(2-hy­droxy­eth­yl)-N,N,N',N'-tetra­methyl­propane-1,3-diaminium ligand (L) (the other half being generated by a twofold rotation axis), and three bromide ions. The MnII cation is coordinated by a single L ligand via the hy­droxy O atom and by five bromide ions, resulting in a distorted octa­hedral MnBr5O coordination geometry. Four of the bromide ions are bridging to two adjacent MnII atoms, thereby forming polymeric chains along the a and b axes. The L units act as links between neighbouring Mn-([mu]-Br)2-Mn chains, also forming a polymeric continuum along the c axis, which completes the formation of a three-dimensional network. Classical O-H...Br hydrogen bonds are present. The distance between adjacent MnII atoms is 4.022 (1) Å.

Comment top

Solid state chemistry of metal halides has been widely studied in order to improve various magnetic and non-linear optical applications. In the crystal structure of the type MX4L2, the bridging qualities of the halide anions and the coordination properties of the organic ligands result in various polymeric structures. For example, one-dimensional M-(µ-X)2M bridged chains with low-dimensional arrangement have more suitable magnetic properties than classic structures of layered metal halide salts (Han et al. 2012; Wang et al. 2011 and Hitchcock et al. 2003).

The title compound, [MnII(µ-Br)2µ-(C11H28N2O2)Br]n, crystallizes in a tetragonal P43212 crystal system showing one MnII cation, half of a dicationic [C11H28N2O2]2+ ligand (L) and three bromide anions in an asymmetric unit (Fig. 1). In this three-dimensional polymer each MnII cation is coordinated by four bridging bromo anions in the equatorial plane. A single terminal bromo anion and a ligand are located in the axial positions of the distorted octahedron showing axial Br3—Mn1—O1 angle of 174.03 (8)°. The three-dimensional network structure comprises two alternating crossed Mn-(µ-Br)2—Mn chains (a- and b-axes) and an undulated L—Mn-(µ-Br)2—Mn—L chain (c-axis). Distances between parallel Mn-(µ-Br)2—Mn chains (planes through Mn -centres) are about 17.656 Å and between anti-parallel chains 8.7825 Å. This allows a formation of a structure model having alternating organic cation and a metal halide layers along c-axis (Figures 2 & 3).

In MnII cation coordination environment, the terminal Br- anion fulfills the coordination of the MnII cation to octahedral MnBr5O. The metal–metal distance along the resulting chain of octahedra is 4.022 (1) Å. All the equatorial Mn—Br bridge bond distances are almost identical but still somewhat longer than the axial Mn1—Br3 bond. The bridging bromides and the adjacent Mn -centers form folded square-planar geometry, showing nearly orthogonal contact angle of 94.05 (2)° via Mn4—Br2- Mn4 atoms, and torsion angle of 12.82 (2)° through Mn4—Br2—Mn4—Br1 atoms.

In the structure, the ligands are in S-shaped conformation between the anti-parallel Mn-(µ-Br)2—Mn chains (Fig. 4). It seems that S-conformation is an ideal conformation for this type of relatively flexible ditopic ligand (Kärnä et al. 2010). The torsion angle C2—N4—N4—C2 is 156.70°. Similar cation conformations are found in ion pair structures [ZnIIBr4(C11H28N2O2)] and (C11H28N2O2) Br2 H2O.

Classical Br3···H–O1 hydrogen bonds are present in the MnII cation coordination environment between the terminal Br- anions of MnII cation and the hydroxyl group of the neighboring metal center (Fig. 5). Hence, it seems likely that in the parent complex the hydrogen bonding steers the oxygen's coordination to the MnII cation. Weak interactions between O1 and halide bridge on the other side of Br1 and Br2 leads to distortions of chains torsion angle. The angle between the Mn1—Br1—Br2 and Mn1—Br1—Br2 planes is 162.6°. For this reason, Mn-(µ-Br)2—Mn chains zigzag-conformation (Fig. 6).

Related literature top

For related structures of MII transition metal halide one-dimensional coordination polymers, see: Han et al. (2012); Englert & Schiffers (2006). For two-dimensional networks, see: Hu & Englert (2006); Turgunov et al. (2011). For properties of metal halides, see: Hitchcock et al. (2003); Wang et al. (2011). For ligand conformations, see: Kärnä et al. (2010).

Experimental top

The single crystals of the title compound were obtained in the following two steps: First, dicationic bromide salt, as the precursor, was synthesized in 30 ml of acetone by reacting 2.20 ml (13.15 mmol) of TMPDA, C7H18N2, and 2.16 ml (28.93 mmol) of 2-bromo-1-ethanol, C2H5BrO, for 48 h at 60 °C in a sealed flask. After removing the solvent, the white precipitation was washed by acetone and dried in vacuo (yield 71.6%; 3.58 g).

1H-NMR (DMSO, 250 MHz, p.p.m.): 2.08–2.32 (2H, m, CH2—CH2-CH2), 3.16 (12H, s, N—CH3), 3.31 (2H, s, H2O), 3.37–3.43 (4H, t, HO—CH2—CH2-N), 3.48–3.52 (4H, t, N—CH2-CH2—CH2-N), 3.84 (4H, s, CH2-OH), 5.29–5.33 (2H, t, OH)

Second, the precursor salt and the dried MnBr2 4H2O (molar ratio ~1:1.5) were dissolved separately in minimum volume of warm methanol before combining the solutions. The title compound was synthesized in an open flask by metathesis reaction of the two aforementioned salts. The combined solution was stirred for about 1 h at 40 °C after which it was slowly cooled to RT and methanol was allowed to evaporate slowly. After several days, purple crystals suitable for X-ray analysis were formed.

Refinement top

Hydrogen atoms (except of a hydroxyl hydrogen atom that was taken from the electron density map) were calculated to their positions as riding atoms (C host) using isotropic displacement parameters that were fixed to be 1.2 or 1.5 times larger than those of the attached non-hydrogen atom.

Computing details top

Data collection: COLLECT (Bruker, 2008); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: Mercury (Macrae et al. 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008b).

Figures top
[Figure 1] Fig. 1. Asymmetric unit and labeling scheme of the title compound. Ellipsoids are presented at the 50% probability level.
[Figure 2] Fig. 2. The one-dimensional linear chain with (µ-Br)2 bridges, Mn···Mn contact with a distance of 4.022 (1) Å and hydrogen bonding scheme.
[Figure 3] Fig. 3. Undulated network formed by the L ligands connecting the alternating crossed Mn-(µ-Br)2—Mn chains, viewed along b-axis.
[Figure 4] Fig. 4. S-shaped conformation of the ligands (only ligand backbone showed) between the anti-parallel Mn-(µ-Br)2—Mn slightly distorted octahedron chains.
[Figure 5] Fig. 5. The structure is stabilized by weak intermolecular interactions between Br3 and nearby ligands.
[Figure 6] Fig. 6. Zigzag tilting of the adjacent MnBr5O octahedra.
Poly[[µ-N,N'-bis(2-hydroxyethyl)- N,N,N',N'-tetramethylpropane-1,3-diaminium- κ2O:O']tetra-µ-bromido-dibromidodimanganese(II)] top
Crystal data top
[Mn2Br6(C11H28N2O2)]Dx = 2.370 Mg m3
Mr = 809.69Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212Cell parameters from 1871 reflections
Hall symbol: P 4nw 2abwθ = 0.4–27.9°
a = 8.0163 (4) ŵ = 11.69 mm1
c = 35.3103 (18) ÅT = 123 K
V = 2269.1 (2) Å3Block, violet
Z = 40.25 × 0.25 × 0.20 mm
F(000) = 1536
Data collection top
Bruker–NoniusKappa APEXII
1966 independent reflections
Radiation source: fine-focus sealed tube1856 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
Detector resolution: 9 pixels mm-1θmax = 25.0°, θmin = 2.8°
ϕ and ω scansh = 99
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
k = 49
Tmin = 0.440, Tmax = 0.746l = 2241
5076 measured reflections
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)] = 0.021H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.047 w = 1/[σ2(Fo2) + (0.P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max = 0.001
1966 reflectionsΔρmax = 0.36 e Å3
111 parametersΔρmin = 0.41 e Å3
1 restraintAbsolute structure: Flack (1983), 690 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.048 (14)
Crystal data top
[Mn2Br6(C11H28N2O2)]Z = 4
Mr = 809.69Mo Kα radiation
Tetragonal, P43212µ = 11.69 mm1
a = 8.0163 (4) ÅT = 123 K
c = 35.3103 (18) Å0.25 × 0.25 × 0.20 mm
V = 2269.1 (2) Å3
Data collection top
Bruker–NoniusKappa APEXII
1966 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
1856 reflections with I > 2σ(I)
Tmin = 0.440, Tmax = 0.746Rint = 0.032
5076 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.021H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.047Δρmax = 0.36 e Å3
S = 1.02Δρmin = 0.41 e Å3
1966 reflectionsAbsolute structure: Flack (1983), 690 Friedel pairs
111 parametersAbsolute structure parameter: 0.048 (14)
1 restraint
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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*/UeqOcc. (<1)
C20.8227 (5)0.8960 (5)0.15487 (11)0.0158 (9)
C30.8705 (5)0.7633 (5)0.18350 (10)0.0143 (9)
C50.6146 (5)0.7687 (6)0.22206 (11)0.0197 (10)
C60.8652 (5)0.6412 (5)0.24628 (11)0.0172 (10)
C70.8412 (5)0.9495 (5)0.24099 (11)0.0116 (9)
C81.0268 (5)0.9732 (5)0.25000.0140 (13)
N40.8013 (4)0.7825 (4)0.22294 (9)0.0130 (8)
O10.9205 (3)1.0470 (4)0.15874 (8)0.0140 (6)
Br10.61915 (5)1.32320 (5)0.175357 (11)0.01348 (10)
Br21.13256 (5)1.39037 (5)0.167113 (10)0.01205 (10)
Br30.81111 (5)1.55274 (5)0.090982 (11)0.01279 (11)
Mn10.87136 (8)1.27065 (7)0.124710 (17)0.01152 (14)
H11.010 (3)1.021 (5)0.1575 (13)0.017*
Atomic displacement parameters (Å2) top
C20.024 (2)0.0120 (19)0.011 (2)0.004 (2)0.003 (2)0.0030 (18)
C30.021 (2)0.014 (2)0.009 (2)0.001 (2)0.0015 (19)0.0001 (17)
C50.013 (2)0.025 (2)0.021 (2)0.001 (2)0.001 (2)0.006 (2)
C60.023 (2)0.013 (2)0.015 (2)0.0018 (19)0.0049 (19)0.0016 (18)
C70.015 (2)0.0074 (18)0.012 (2)0.0020 (19)0.0027 (18)0.0025 (17)
C80.0114 (19)0.0114 (19)0.019 (3)0.002 (3)0.0015 (19)0.0015 (19)
N40.0139 (16)0.0157 (17)0.0094 (17)0.0011 (16)0.0017 (14)0.0004 (15)
O10.0105 (14)0.0137 (14)0.0178 (15)0.0010 (13)0.0016 (14)0.0026 (14)
Br10.01241 (19)0.0168 (2)0.01122 (19)0.00105 (19)0.00124 (18)0.00200 (18)
Br20.01210 (19)0.01371 (19)0.01035 (19)0.00068 (18)0.00073 (16)0.00004 (17)
Br30.01400 (19)0.01200 (19)0.0124 (2)0.00096 (19)0.00056 (18)0.00178 (17)
Mn10.0117 (3)0.0115 (3)0.0113 (3)0.0001 (3)0.0003 (3)0.0014 (3)
Geometric parameters (Å, º) top
C2—O11.449 (5)C7—C81.533 (5)
C2—C31.517 (5)C7—H7A0.9900
C2—H2B0.9900C8—C7i1.533 (5)
C3—N41.507 (4)C8—H8A0.9900
C3—H3B0.9900O1—Mn12.194 (3)
C5—N41.501 (5)O1—H10.748 (19)
C5—H5A0.9800Br1—Mn12.7319 (7)
C5—H5B0.9800Br1—Mn1ii2.7635 (7)
C5—H5C0.9800Br2—Mn1iii2.7407 (7)
C6—N41.491 (5)Br2—Mn12.7472 (8)
C6—H6A0.9800Br3—Mn12.6010 (7)
C6—H6B0.9800Mn1—Br2ii2.7407 (7)
C6—H6C0.9800Mn1—Br1iii2.7635 (7)
C7—N41.517 (5)
O1—C2—C3112.7 (3)C7i—C8—H8A110.4
H2A—C2—H2B107.8C6—N4—C5107.3 (3)
N4—C3—C2116.8 (3)C6—N4—C3107.9 (3)
N4—C3—H3A108.1C5—N4—C3109.9 (3)
C2—C3—H3A108.1C6—N4—C7111.4 (3)
N4—C3—H3B108.1C5—N4—C7106.5 (3)
C2—C3—H3B108.1C3—N4—C7113.6 (3)
H3A—C3—H3B107.3C2—O1—Mn1122.3 (2)
N4—C5—H5A109.5C2—O1—H1106 (4)
N4—C5—H5B109.5Mn1—O1—H1112 (4)
H5A—C5—H5B109.5Mn1—Br1—Mn1ii94.082 (12)
N4—C5—H5C109.5Mn1iii—Br2—Mn194.254 (12)
H5A—C5—H5C109.5O1—Mn1—Br3174.03 (8)
H5B—C5—H5C109.5O1—Mn1—Br184.28 (8)
N4—C6—H6A109.5Br3—Mn1—Br191.62 (2)
N4—C6—H6B109.5O1—Mn1—Br2ii92.05 (8)
H6A—C6—H6B109.5Br3—Mn1—Br2ii91.89 (2)
N4—C6—H6C109.5Br1—Mn1—Br2ii84.75 (2)
H6A—C6—H6C109.5O1—Mn1—Br281.38 (8)
H6B—C6—H6C109.5Br3—Mn1—Br295.01 (2)
N4—C7—C8113.7 (3)Br1—Mn1—Br298.83 (2)
N4—C7—H7A108.8Br2ii—Mn1—Br2172.12 (3)
C8—C7—H7A108.8O1—Mn1—Br1iii89.94 (8)
N4—C7—H7B108.8Br3—Mn1—Br1iii94.43 (2)
C8—C7—H7B108.8Br1—Mn1—Br1iii173.07 (2)
H7A—C7—H7B107.7Br2ii—Mn1—Br1iii91.67 (2)
C7i—C8—C7106.5 (4)Br2—Mn1—Br1iii84.03 (2)
O1—C2—C3—N479.7 (4)C2—O1—Mn1—Br2179.1 (3)
N4—C7—C8—C7i167.0 (4)C2—O1—Mn1—Br1iii96.9 (3)
C2—C3—N4—C6179.3 (3)Mn1ii—Br1—Mn1—O1105.44 (8)
C2—C3—N4—C564.0 (5)Mn1ii—Br1—Mn1—Br378.92 (2)
C2—C3—N4—C755.2 (5)Mn1ii—Br1—Mn1—Br2ii12.838 (12)
C8—C7—N4—C654.1 (4)Mn1ii—Br1—Mn1—Br2174.24 (3)
C8—C7—N4—C5170.8 (3)Mn1iii—Br2—Mn1—O178.06 (8)
C8—C7—N4—C368.1 (4)Mn1iii—Br2—Mn1—Br3106.73 (2)
C3—C2—O1—Mn1175.3 (2)Mn1iii—Br2—Mn1—Br1160.85 (3)
C2—O1—Mn1—Br179.3 (3)Mn1iii—Br2—Mn1—Br1iii12.785 (11)
C2—O1—Mn1—Br2ii5.2 (3)
Symmetry codes: (i) y+2, x+2, z+1/2; (ii) x1/2, y+5/2, z+1/4; (iii) x+1/2, y+5/2, z+1/4.
Hydrogen-bond geometry (Å, º) top
O1—H1···Br3iii0.75 (2)2.49 (2)3.232 (3)175 (5)
Symmetry code: (iii) x+1/2, y+5/2, z+1/4.

Experimental details

Crystal data
Chemical formula[Mn2Br6(C11H28N2O2)]
Crystal system, space groupTetragonal, P43212
Temperature (K)123
a, c (Å)8.0163 (4), 35.3103 (18)
V3)2269.1 (2)
Radiation typeMo Kα
µ (mm1)11.69
Crystal size (mm)0.25 × 0.25 × 0.20
Data collection
DiffractometerBruker–NoniusKappa APEXII
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2008a)
Tmin, Tmax0.440, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections
5076, 1966, 1856
(sin θ/λ)max1)0.595
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.047, 1.02
No. of reflections1966
No. of parameters111
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.36, 0.41
Absolute structureFlack (1983), 690 Friedel pairs
Absolute structure parameter0.048 (14)

Computer programs: COLLECT (Bruker, 2008), DENZO-SMN (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), Mercury (Macrae et al. 2008).

Hydrogen-bond geometry (Å, º) top
O1—H1···Br3i0.748 (19)2.49 (2)3.232 (3)175 (5)
Symmetry code: (i) x+1/2, y+5/2, z+1/4.
Acknowledgements top

The financial support of University of Jyväskylä is gratefully acknowledged.