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Acta Cryst. (2013). E69, m185-m186    [ doi:10.1107/S1600536813005618 ]

Poly[[([mu]4-1,3,5-triamino-1,3,5-tride­oxy-cis-inositol)sodium] bromide]

G. J. Reiss and K. Hegetschweiler

Abstract top

In the structure of the title compound, {[Na(C6H15N3O3)]Br}n, the sodium cation and the bromide anion are both located on threefold rotation axes. The sodium cation is bonded to the three hy­droxy groups of one 1,3,5-triamino-1,3,5-tride­oxy-cis-inositol (taci) ligand, with the taci ligand residing around the same threefold rotation axis as the sodium ion. The coordination sphere of the sodium ion is completed by three amino groups of three neighbouring taci mol­ecules. Hence, this type of coordination constitutes a three-dimensional open framework with channels along the c axis which are filled with the bromide counter-anions. Each bromide ion forms three symmetry-related hydrogen bonds to both the hy­droxy and the amino groups of neighbouring taci ligands.

Comment top

The coordination ability of 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (= taci) attracted attention owing to the two distinct chair conformations of this ligand, allowing metal binding either via three axial nitrogen or three axial oxygen donors (Hegetschweiler, 1999). For the free taci ligand and its protonation products, a chair conformation with axial hydroxy groups has been asserted (Reiss et al., 1999). However, binding of divalent transition metal cations such as Cu2+ usually occurs via three axial amino groups (Reiss et al., 1998). The binding of Na+ to a protonated bis-taci unit (where two taci-moieties are connected via a O—CH2—CH2—O bridge) occurred via the axial hydroxy groups (Bartholomä et al., 2010).

In the title compound, [Na(C6H15N3O3)]+Br-, the cation, anion and the taci ligand have site symmetry 3. The taci ligand also adopts a chair conformation with axial hydroxy groups, which bind to the Na+ cation (Na—O distance: 2.409 (4)Å). The puckering parameters (Cremer & Pople, 1975) of the cyclohexane ring are Q = 0.531Å, ϕ = 0.0°, θ = 180.0°. Interlinking of the Na+ cation to three equatorial amino groups of three neighbouring taci ligands (Na—N distance: 2.556 (4)Å) generates a distorted octahedral coordination geometry around the sodium ion. Due to symmetry, the three oxygen and the three nitrogen donors form each two parallel, equilateral triangles with a twist angle τ of 56.4°. This value indicates that the fac-NaO3N3 coordination geometry adopts C3v symmetry quite closely. The bromide anion is hydrogen-bonded to three hydroxy groups of three adjacent taci ligands. Additionally, three N—H···Br contacts are formed (see Table 1). These N—H···Br contacts may be interpreted as weak hydrogen bonds. The three (N—)H and the three (O—)H hydrogen atoms form again two parallel, equilateral triangles with a twist angle τ = 32.4°. The six hydrogen atoms, which encapsulate the bromide ion, constitute thus a polyhedron which is just an intermediate form between a trigonal prism (τ = 0°) and a trigonal antiprism (τ = 60°). Notably, the bromide ion is not located in the centre of this polyhedron. It is significantly displaced towards the three (O—)H hydrogen atoms. Inspection of the structure further reveals an intermolecular N···O separation of 2.831 (6)Å, a value which falls in a range expected for N—H···O hydrogen bonding. However, the corresponding N—H···O angle of 110 (6)° is very acute and would not be in agreement with such an interpretation.

Related literature top

The crystal structure of an Na–bis-taci complex has been reported by Bartholomä et al. (2010). Puckering parameters were calculated according to Cremer & Pople (1975). For a preliminary preparation and characterization of the title compound, see: Egli (1994). For a general overview of the coordination chemistry of taci, see: Hegetschweiler (1999). The crystal structure of a CuII–taci complex has been reported by Reiss et al. (1998). For the crystal structure of a monoprotonated taci salt, see: Reiss et al. (1999).

Experimental top

The title compound was first isolated unintentionally by Egli (1994) in the reaction of K2ReBr6, NaOCH3 and taci. In our study, it was prepared by adding equimolar amounts of NaBr and taci in small portions to boiling MeOH until a saturated solution was obtained. The solution was filtered hot and was allowed to cool slowly to room temperature, yielding colourless single crystals suitable for crystal structure analysis.

Refinement top

All hydrogen atoms were identified in difference syntheses. In the latest stages of refinement, the coordinates of the N– and C– bonded hydrogen atoms were refined, whereas the coordinates of the (O—)H hydrogen atom had to be constrained using the AFIX 83 option of the SHELXL program. The N—H bond lengths were restrained to 0.90Å. All Uiso values, besides those of the CH groups, were refined freely.

Computing details top

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS (Siemens, 1994); data reduction: XSCANS (Siemens, 1994) and XPREP (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Ellipsoid plot and numbering scheme of a Br anion and an Na(taci) moiety together with the coordinating amino groups of three additional, neighbouring taci units. Displacement parameters are given at the 50% probability level.
[Figure 2] Fig. 2. Section of the extended network of the title compound viewed along the c axis.
Poly[[(µ4-1,3,5-triamino-1,3,5-trideoxy-cis-inositol)sodium] bromide] top
Crystal data top
[Na(C6H15N3O3)]BrDx = 1.864 Mg m3
Mr = 280.10Mo Kα radiation, λ = 0.71073 Å
Trigonal, P31cCell parameters from 99 reflections
Hall symbol: P 3 -2cθ = 6.6–14.9°
a = 8.0491 (10) ŵ = 4.15 mm1
c = 8.8953 (18) ÅT = 153 K
V = 499.10 (13) Å3Block, colorless
Z = 20.57 × 0.45 × 0.28 mm
F(000) = 284
Data collection top
Siemens P4
682 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.077
Graphite monochromatorθmax = 26.5°, θmin = 2.9°
ω scanh = 99
Absorption correction: integration
(XPREP; Bruker, 2008) using indexed faces
k = 1010
Tmin = 0.101, Tmax = 0.331l = 1111
3954 measured reflections3 standard reflections every 100 reflections
690 independent reflections intensity decay: none
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.015P)2 + 2.P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.078(Δ/σ)max < 0.001
S = 1.05Δρmax = 0.42 e Å3
690 reflectionsΔρmin = 0.55 e Å3
59 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
3 restraintsExtinction coefficient: 0.024 (4)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), 340 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.03 (3)
Crystal data top
[Na(C6H15N3O3)]BrZ = 2
Mr = 280.10Mo Kα radiation
Trigonal, P31cµ = 4.15 mm1
a = 8.0491 (10) ÅT = 153 K
c = 8.8953 (18) Å0.57 × 0.45 × 0.28 mm
V = 499.10 (13) Å3
Data collection top
Siemens P4
682 reflections with I > 2σ(I)
Absorption correction: integration
(XPREP; Bruker, 2008) using indexed faces
Rint = 0.077
Tmin = 0.101, Tmax = 0.3313 standard reflections every 100 reflections
3954 measured reflections intensity decay: none
690 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.078Δρmax = 0.42 e Å3
S = 1.05Δρmin = 0.55 e Å3
690 reflectionsAbsolute structure: Flack (1983), 340 Friedel pairs
59 parametersAbsolute structure parameter: 0.03 (3)
3 restraints
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
Na0.33330.66670.1288 (3)0.0163 (6)
Br1.00001.00000.22830 (19)0.0196 (3)
N10.6544 (6)0.6032 (6)0.4871 (4)0.0180 (8)
H1N0.638 (9)0.569 (8)0.390 (2)0.027 (15)*
H2N0.768 (4)0.707 (5)0.508 (7)0.024 (14)*
C10.4981 (6)0.6393 (6)0.5290 (5)0.0141 (9)
H10.494 (8)0.637 (8)0.627 (5)0.017*
C20.5288 (6)0.8341 (6)0.4803 (5)0.0144 (9)
H20.638 (8)0.926 (8)0.526 (6)0.017*
O10.5558 (4)0.8645 (5)0.3206 (3)0.0155 (6)
H1O0.66890.90490.29980.023 (15)*
Atomic displacement parameters (Å2) top
Na0.0170 (9)0.0170 (9)0.0148 (13)0.0085 (5)0.0000.000
Br0.0178 (3)0.0178 (3)0.0232 (4)0.00892 (14)0.0000.000
N10.0150 (18)0.023 (2)0.0201 (19)0.0123 (16)0.0004 (16)0.0018 (17)
C10.016 (2)0.021 (2)0.0103 (19)0.0130 (19)0.0007 (17)0.0021 (18)
C20.016 (2)0.015 (2)0.0085 (18)0.0055 (18)0.0035 (17)0.0003 (17)
O10.0137 (16)0.0197 (16)0.0122 (13)0.0076 (14)0.0021 (13)0.0031 (12)
Geometric parameters (Å, º) top
Na—O1i2.409 (4)N1—H2N0.900 (10)
Na—O12.409 (4)C1—C21.523 (6)
Na—O1ii2.409 (4)C1—C2ii1.526 (6)
Na—N1iii2.556 (4)C1—H10.87 (5)
Na—N1iv2.556 (4)C2—O11.440 (5)
Na—N1v2.556 (4)C2—C1i1.526 (6)
N1—C11.473 (5)C2—H20.91 (6)
N1—Navi2.556 (4)O1—H1O0.8200
N1—H1N0.895 (10)
O1i—Na—O175.37 (13)C1—N1—H2N110 (4)
O1i—Na—O1ii75.37 (13)Navi—N1—H2N103 (4)
O1—Na—O1ii75.37 (13)H1N—N1—H2N114 (5)
O1i—Na—N1iii94.37 (12)N1—C1—C2114.6 (4)
O1—Na—N1iii164.19 (15)N1—C1—C2ii110.1 (4)
O1ii—Na—N1iii90.53 (12)C2—C1—C2ii113.7 (4)
O1i—Na—N1iv90.53 (12)N1—C1—H1106 (4)
O1—Na—N1iv94.37 (12)C2—C1—H1107 (4)
O1ii—Na—N1iv164.19 (15)C2ii—C1—H1105 (4)
N1iii—Na—N1iv97.78 (14)O1—C2—C1112.9 (3)
O1i—Na—N1v164.19 (15)O1—C2—C1i109.1 (4)
O1—Na—N1v90.53 (12)C1—C2—C1i110.8 (4)
O1ii—Na—N1v94.37 (12)O1—C2—H2107 (3)
N1iii—Na—N1v97.78 (14)C1—C2—H2108 (4)
N1iv—Na—N1v97.78 (14)C1i—C2—H2109 (3)
C1—N1—Navi116.3 (3)C2—O1—Na126.0 (3)
C1—N1—H1N107 (4)C2—O1—H1O109.5
Navi—N1—H1N106 (4)Na—O1—H1O114.4
Navi—N1—C1—C2162.1 (3)C1i—C2—O1—Na65.3 (4)
Navi—N1—C1—C2ii68.3 (4)O1i—Na—O1—C241.5 (3)
N1—C1—C2—O157.6 (5)O1ii—Na—O1—C236.9 (3)
C2ii—C1—C2—O170.2 (5)N1iii—Na—O1—C29.3 (6)
N1—C1—C2—C1i179.8 (3)N1iv—Na—O1—C2130.9 (3)
C2ii—C1—C2—C1i52.5 (6)N1v—Na—O1—C2131.3 (3)
C1—C2—O1—Na58.3 (5)
Symmetry codes: (i) y+1, xy+1, z; (ii) x+y, x+1, z; (iii) xy, y+1, z1/2; (iv) x+1, x+y+1, z1/2; (v) y, x, z1/2; (vi) y, x, z+1/2.
Hydrogen-bond geometry (Å, º) top
O1—H1O···Br0.822.463.278 (3)175
N1—H2N···Brvi0.90 (1)2.91 (3)3.696 (4)147 (5)
Symmetry code: (vi) y, x, z+1/2.

Experimental details

Crystal data
Chemical formula[Na(C6H15N3O3)]Br
Crystal system, space groupTrigonal, P31c
Temperature (K)153
a, c (Å)8.0491 (10), 8.8953 (18)
V3)499.10 (13)
Radiation typeMo Kα
µ (mm1)4.15
Crystal size (mm)0.57 × 0.45 × 0.28
Data collection
DiffractometerSiemens P4
Absorption correctionIntegration
(XPREP; Bruker, 2008) using indexed faces
Tmin, Tmax0.101, 0.331
No. of measured, independent and
observed [I > 2σ(I)] reflections
3954, 690, 682
(sin θ/λ)max1)0.627
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.078, 1.05
No. of reflections690
No. of parameters59
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.42, 0.55
Absolute structureFlack (1983), 340 Friedel pairs
Absolute structure parameter0.03 (3)

Computer programs: , XSCANS (Siemens, 1994) and XPREP (Bruker, 2008), SHELXS97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2012), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
O1—H1O···Br0.822.463.278 (3)175.3
N1—H2N···Bri0.900 (10)2.91 (3)3.696 (4)147 (5)
Symmetry code: (i) y, x, z+1/2.
Acknowledgements top

no acknowledgement