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ISSN: 2056-9890

Crystal structure of tri­hydrogen bis­­{[1,1,1-tris­­(2-oxido­ethyl­amino­meth­yl)ethane]­cobalt(III)} trinitrate

aDepartment of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
*Correspondence e-mail: weihe@kiku.dk

Edited by V. V. Chernyshev, Moscow State University, Russia (Received 7 December 2015; accepted 22 December 2015; online 31 December 2015)

The title compound, [Co2(L)2]3+·3NO3 [where L = CH3C(CH2NHCH2CH2OH1/2)3], has been synthesized from the ligand 1,1,1-tris­(2-hy­droxy­ethyl­amino­meth­yl)ethane. The cobalt(III) dimer has an inter­esting and uncommon O—H⋯O hydrogen-bonding motif with the three bridging hy­droxy H atoms each being equally disordered over two positions. In the dimeric trication, the octa­hedrally coordinated CoIII atoms and the capping C atoms lie on a threefold rotation axis. The N atoms of two crystallographically independent nitrate anions also lie on threefold rotation axes. N—H⋯O hydrogen bonding between the complex cations and nitrate anions leads to the formation of a three-dimensional network structure. The compound is a racemic conglomerate of crystals containing either D or L mol­ecules. The crystal used for this study is a D crystal.

1. Related literature

For the crystal structure of the related cis-aqua­hydroxido complex of chromium(III), see: Ardon et al. (1987[Ardon, M., Bino, A. & Michelsen, K. (1987). J. Am. Chem. Soc. 109, 1986-1990.]).

[Scheme 1]

2. Experimental

2.1. Crystal data

  • [Co2(C11H25.5N3O3)2](NO3)3

  • Mr = 799.57

  • Trigonal, R 32

  • a = 8.543 (4) Å

  • c = 39.11 (2) Å

  • V = 2472 (3) Å3

  • Z = 3

  • Mo Kα radiation

  • μ = 1.09 mm−1

  • T = 122 K

  • 0.31 × 0.25 × 0.15 mm

2.2. Data collection

  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2014[Bruker (2014). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.601, Tmax = 0.746

  • 32729 measured reflections

  • 1357 independent reflections

  • 1263 reflections with I > 2σ(I)

  • Rint = 0.074

2.3. Refinement

  • R[F2 > 2σ(F2)] = 0.021

  • wR(F2) = 0.048

  • S = 0.81

  • 1357 reflections

  • 81 parameters

  • 3 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.24 e Å−3

  • Δρmin = −0.43 e Å−3

  • Absolute structure: Flack x determined from 486 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons & Flack, 2004[Parsons, S. & Flack, H. (2004). Acta Cryst. A60, s61.])

  • Absolute structure parameter: 0.011 (8)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯O1i 0.86 (1) 1.59 (1) 2.445 (2) 172 (4)
N1—H1A⋯O2 0.98 2.09 3.042 (3) 163
Symmetry code: (i) y, x, -z+1.

Data collection: APEX2 (Bruker, 2012[Bruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2012[Bruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT (Bruker, 2012[Bruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: olex2.solve (Bourhis et al., 2015[Bourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59-75.]); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]); molecular graphics: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: OLEX2.

Supporting information


Comment top

We present here a new hexadentate ligand which, when coordinated to a metal center, facilitates dimer formation through H-bonding (Fig. 1, Table 1). This type of structural motif is rare, but some examples exist in the literature, for example cis-aqua-hydroxo complexes of chromium(III) (Ardon et al., 1987).

The ligand, 1,1,1-tris(2-hydroxyethylaminomethyl)ethane, is synthesised from 1,1,1-tris (bromomethyl)ethane and ethanolamine and purified by destillation and column chromatography producing the trihydrochloride. Reaction of a suitable metal salt such as Co(NO3)2˙6H2O and oxidation with hydrogen peroxide affords the title compound (the nitrate salt is much less soluble than the chloride salt).

The title compound, large pink hexagonal single crystals, crystalises in the trigonal space group R32 with the Co-Co axis along the trigonal axis. The compound synthesised is racemic, but upon crystallisation it resolves spontaneously to produce a racemic conglamorate. The crystal mounted contains the Δ-form as indicated by a Flack parameter of 0.011 (8) (if the structure is inverted, R1 doubles).

The coordination geometry around the Co ions are close to octahedral with the Co1-N1 distance being 1.95111 (18) Å and the Co1-O1 distance being 1.9314 (14) Å. The O1-Co1-O1 angles are 91.01 (6) ° and the N1-Co1-N1 angles are 92.38 (7) °. The three bridging H-atoms could not be completely located in the Fourier map and were added with a riding model. However, because of the high symmetry and disorder, six equivalent H atom positions exist with the occupancies fixed to 0.5. ORTEP plot in Fig. 1 shows all six possible positions. Solving the structure in a space group of lower symmetry does not resolve three hydrogens in the trigonal prism formed by the six oxygen atoms, and we take this as a sign that the three H-atoms are disordered over the six positions. The Co-Co distance in the dimer, which is of interrest in regards to future analogues with paramagnetic metal ions, is 4.607 (2) Å. This could give interesting magnetic characteristics for the metal ions like Cr(III) and Mn(III).

Related literature top

For the crystal structure of the related cis-aquahydroxido complex of chromium(III), see: Ardon et al. (1987).

Experimental top

Synthesis of the ligand: 1,1,1-tris(bromomethyl)- ethane (60g, 0,20 mol) was dissolved in ethanolamine (200ml, 3,3 mol) in a flask fitted with a condenser and a nitrogen in and outlet. After the system was flushed with nitrogen 10-15 min. the mixture was refluxed (170 °C) for 4 hours under continued nitrogen flow. The result is a clear pale yellow oil. To remove surplus ethanolamine the reaction mixture was azeotropically distilled using Chlorobenzene (b.p. at approx. 128 °C). After approximately one week ethanolamonium bromide crystallizes and can be removed by filtration. The resulting oil was disolved in 1M HCl is put on a cation exchange column (AG 50W-X2 cation exchange resin (H±form), 5x50cm) and washed with copious amounts of water. The column is then eleuted with 1M HCl followed by 2M HCl to remove excess ethanolamine. Finally, the column was eluted with 3M HCl to isolate the product. The 3M HCl eluate was evaporated to dryness to get the product as the hydrochloride salt (an oil). The yield was around 40-50 %. 1H NMR (D2O): δ = 1.03 (3 H, -CH3), 2.94 (6 H, {-CH2}3), 3.05(6 H, {-CH2}3), 3.52 (6 H, {-CH2}3) ppm. C11H24N3O3˙3HCl˙10H2O (535.9): calcd. C 24.65, N 7.84; found C 24.88, N 7.91.

Synthesis of the title compound: 3 g (10 mmol) Co(NO3)2˙6H2O is dissolved in 10 ml water. 5 g (10 mmol) CH3C(CH2NHC2H4OH)3˙3HCl˙10H2O is dissolved in 10 ml water and added dropwise to the CoII solution. 0.6 g (6 mmol) trimethylamine is also added to the reaction mixture. Concentrated H2O2 is added dropwise to the reaction mixture until a red powder precipitates. The red powder can be recrystallized from water. Yield: 1.77 g (45 %). Co2H45C22N9O15 (793.518): calcd. C 33.30, N 15.89; found C 33.31, N 15.07.

Refinement top

H atoms were geometrically positioned and refined as riding. The hydroxy atom H1 was placed in the calculated position with occupncy fixed to 0.5, and refined with bond restraint of O—H = 0.87 (1) Å.

Structure description top

We present here a new hexadentate ligand which, when coordinated to a metal center, facilitates dimer formation through H-bonding (Fig. 1, Table 1). This type of structural motif is rare, but some examples exist in the literature, for example cis-aqua-hydroxo complexes of chromium(III) (Ardon et al., 1987).

The ligand, 1,1,1-tris(2-hydroxyethylaminomethyl)ethane, is synthesised from 1,1,1-tris (bromomethyl)ethane and ethanolamine and purified by destillation and column chromatography producing the trihydrochloride. Reaction of a suitable metal salt such as Co(NO3)2˙6H2O and oxidation with hydrogen peroxide affords the title compound (the nitrate salt is much less soluble than the chloride salt).

The title compound, large pink hexagonal single crystals, crystalises in the trigonal space group R32 with the Co-Co axis along the trigonal axis. The compound synthesised is racemic, but upon crystallisation it resolves spontaneously to produce a racemic conglamorate. The crystal mounted contains the Δ-form as indicated by a Flack parameter of 0.011 (8) (if the structure is inverted, R1 doubles).

The coordination geometry around the Co ions are close to octahedral with the Co1-N1 distance being 1.95111 (18) Å and the Co1-O1 distance being 1.9314 (14) Å. The O1-Co1-O1 angles are 91.01 (6) ° and the N1-Co1-N1 angles are 92.38 (7) °. The three bridging H-atoms could not be completely located in the Fourier map and were added with a riding model. However, because of the high symmetry and disorder, six equivalent H atom positions exist with the occupancies fixed to 0.5. ORTEP plot in Fig. 1 shows all six possible positions. Solving the structure in a space group of lower symmetry does not resolve three hydrogens in the trigonal prism formed by the six oxygen atoms, and we take this as a sign that the three H-atoms are disordered over the six positions. The Co-Co distance in the dimer, which is of interrest in regards to future analogues with paramagnetic metal ions, is 4.607 (2) Å. This could give interesting magnetic characteristics for the metal ions like Cr(III) and Mn(III).

For the crystal structure of the related cis-aquahydroxido complex of chromium(III), see: Ardon et al. (1987).

Computing details top

Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: olex2.solve (Bourhis et al., 2015); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the dimer cation showing the atomic labels for non-carbon atoms and 50% probability displacement ellipsoids [symmetry codes: (i) -y, x - y, z; (ii) -x + y, -x, z]. H atoms have been removed for clarity, except for the bridging hydroxy H atoms, each of which is disordered over two positions. Dashed lines denote hydrogen bonds.
Trihydrogen bis{[1,1,1-tris(2-oxidoethylaminomethyl)ethane]cobalt(III)} trinitrate top
Crystal data top
[Co2(C11H25.5N3O3)2](NO3)3Dx = 1.611 Mg m3
Mr = 799.57Mo Kα radiation, λ = 0.71073 Å
Trigonal, R32Cell parameters from 6958 reflections
a = 8.543 (4) Åθ = 2.8–28.1°
c = 39.11 (2) ŵ = 1.09 mm1
V = 2472 (3) Å3T = 122 K
Z = 3Prism, pink
F(000) = 12600.31 × 0.25 × 0.15 mm
Data collection top
Bruker APEXII CCD
diffractometer
1263 reflections with I > 2σ(I)
φ and ω scansRint = 0.074
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
θmax = 28.1°, θmin = 2.8°
Tmin = 0.601, Tmax = 0.746h = 1111
32729 measured reflectionsk = 1111
1357 independent reflectionsl = 5051
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.021 w = 1/[σ2(Fo2)]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.048(Δ/σ)max = 0.003
S = 0.81Δρmax = 0.24 e Å3
1357 reflectionsΔρmin = 0.43 e Å3
81 parametersAbsolute structure: Flack x determined from 486 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons & Flack, 2004)
3 restraintsAbsolute structure parameter: 0.011 (8)
Primary atom site location: iterative
Crystal data top
[Co2(C11H25.5N3O3)2](NO3)3Z = 3
Mr = 799.57Mo Kα radiation
Trigonal, R32µ = 1.09 mm1
a = 8.543 (4) ÅT = 122 K
c = 39.11 (2) Å0.31 × 0.25 × 0.15 mm
V = 2472 (3) Å3
Data collection top
Bruker APEXII CCD
diffractometer
1357 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2014)
1263 reflections with I > 2σ(I)
Tmin = 0.601, Tmax = 0.746Rint = 0.074
32729 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.021H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.048Δρmax = 0.24 e Å3
S = 0.81Δρmin = 0.43 e Å3
1357 reflectionsAbsolute structure: Flack x determined from 486 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons & Flack, 2004)
81 parametersAbsolute structure parameter: 0.011 (8)
3 restraints
Special details top

Experimental. Absorption correction: SADABS-2014/3 (Bruker, 2014) was used for absorption correction. wR2(int) was 0.1434 before and 0.0855 after correction. The Ratio of minimum to maximum transmission is 0.8053. The λ/2 correction factor is Not present.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Co10.00000.00000.55889 (2)0.00936 (12)
O10.17219 (17)0.19761 (18)0.53088 (3)0.0118 (3)
H10.176 (5)0.194 (3)0.5089 (3)0.018*0.5
C50.00000.00000.67637 (7)0.0177 (7)
N20.66670.33330.57385 (6)0.0116 (5)
O20.54318 (19)0.3734 (2)0.57427 (4)0.0237 (4)
C30.1892 (3)0.0424 (3)0.62458 (4)0.0143 (4)
H3A0.27630.16660.63040.017*
H3B0.22310.03520.63670.017*
N10.1977 (2)0.0158 (2)0.58647 (4)0.0115 (3)
H1A0.30880.12080.57810.014*
C20.2123 (3)0.1482 (3)0.57812 (4)0.0133 (4)
H2A0.11930.25350.59000.016*
H2B0.32950.12980.58490.016*
C40.00000.00000.63662 (7)0.0130 (6)
C10.1742 (4)0.3620 (2)0.53957 (4)0.0144 (4)
H1B0.07760.36820.52780.017*
H1C0.28850.46590.53300.017*
N30.33330.66670.66670.0389 (11)
O30.33330.5219 (4)0.66670.0790 (12)
H50.123 (2)0.032 (3)0.6841 (4)0.008 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.00673 (14)0.00673 (14)0.01463 (19)0.00336 (7)0.0000.000
O10.0113 (7)0.0081 (7)0.0151 (6)0.0042 (6)0.0011 (5)0.0002 (5)
C50.0201 (11)0.0201 (11)0.0129 (14)0.0100 (6)0.0000.000
N20.0084 (8)0.0084 (8)0.0180 (11)0.0042 (4)0.0000.000
O20.0130 (8)0.0180 (9)0.0423 (8)0.0095 (8)0.0007 (6)0.0011 (6)
C30.0134 (10)0.0152 (10)0.0144 (8)0.0072 (8)0.0034 (7)0.0018 (7)
N10.0107 (9)0.0098 (8)0.0146 (7)0.0055 (7)0.0000 (6)0.0003 (6)
C20.0104 (11)0.0115 (11)0.0213 (9)0.0081 (10)0.0001 (7)0.0014 (7)
C40.0129 (9)0.0129 (9)0.0133 (13)0.0064 (5)0.0000.000
C10.0145 (12)0.0071 (8)0.0211 (8)0.0050 (10)0.0012 (9)0.0014 (6)
N30.0359 (18)0.0359 (18)0.045 (3)0.0179 (9)0.0000.000
O30.087 (3)0.0450 (14)0.119 (3)0.0435 (14)0.060 (2)0.0300 (10)
Geometric parameters (Å, º) top
Co1—O1i1.9313 (14)C3—N11.515 (2)
Co1—O1ii1.9313 (14)C3—C41.543 (2)
Co1—O11.9314 (15)N1—H1A0.9800
Co1—N11.9511 (17)N1—C21.503 (3)
Co1—N1ii1.9511 (18)C2—H2A0.9700
Co1—N1i1.9511 (17)C2—H2B0.9700
O1—H10.861 (12)C2—C1ii1.523 (2)
O1—C11.436 (2)C4—C3ii1.543 (2)
C5—C41.555 (4)C4—C3i1.543 (2)
C5—H50.987 (18)C1—C2i1.523 (2)
N2—O21.2612 (16)C1—H1B0.9700
N2—O2iii1.2612 (16)C1—H1C0.9700
N2—O2iv1.2612 (16)N3—O3v1.237 (3)
C3—H3A0.9700N3—O31.237 (3)
C3—H3B0.9700N3—O3vi1.237 (3)
O1i—Co1—O1ii91.01 (6)Co1—N1—H1A106.7
O1i—Co1—O191.01 (6)C3—N1—Co1116.71 (12)
O1ii—Co1—O191.01 (6)C3—N1—H1A106.7
O1i—Co1—N1i89.92 (7)C2—N1—Co1106.72 (11)
O1—Co1—N1ii177.58 (6)C2—N1—C3112.72 (14)
O1—Co1—N1i86.74 (7)C2—N1—H1A106.7
O1ii—Co1—N1i177.58 (7)N1—C2—H2A110.5
O1i—Co1—N1177.58 (7)N1—C2—H2B110.5
O1ii—Co1—N1ii89.92 (7)N1—C2—C1ii106.35 (14)
O1ii—Co1—N186.74 (7)H2A—C2—H2B108.7
O1—Co1—N189.92 (7)C1ii—C2—H2A110.5
O1i—Co1—N1ii86.74 (7)C1ii—C2—H2B110.5
N1—Co1—N1ii92.37 (7)C3—C4—C5107.78 (11)
N1—Co1—N1i92.37 (7)C3i—C4—C5107.78 (11)
N1i—Co1—N1ii92.37 (7)C3ii—C4—C5107.78 (11)
Co1—O1—H1124.2 (19)C3—C4—C3i111.11 (11)
C1—O1—Co1110.61 (11)C3ii—C4—C3i111.11 (11)
C1—O1—H1107 (2)C3ii—C4—C3111.11 (11)
C4—C5—H5107.8 (10)O1—C1—C2i107.19 (14)
O2iii—N2—O2119.982 (8)O1—C1—H1B110.3
O2iv—N2—O2119.984 (8)O1—C1—H1C110.3
O2iii—N2—O2iv119.983 (8)C2i—C1—H1B110.3
H3A—C3—H3B107.8C2i—C1—H1C110.3
N1—C3—H3A109.0H1B—C1—H1C108.5
N1—C3—H3B109.0O3v—N3—O3vi120.000 (3)
N1—C3—C4112.85 (16)O3vi—N3—O3119.999 (4)
C4—C3—H3A109.0O3v—N3—O3120.001 (9)
C4—C3—H3B109.0
Co1—O1—C1—C2i36.7 (2)N1—C3—C4—C3i71.71 (18)
Co1—N1—C2—C1ii41.38 (17)N1—C3—C4—C3ii52.55 (19)
C3—N1—C2—C1ii170.77 (17)C4—C3—N1—Co116.05 (19)
N1—C3—C4—C5170.42 (11)C4—C3—N1—C2108.00 (16)
Symmetry codes: (i) y, xy, z; (ii) x+y, x, z; (iii) y+1, xy, z; (iv) x+y+1, x+1, z; (v) x+y, x+1, z; (vi) y+1, xy+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O1vii0.86 (1)1.59 (1)2.445 (2)172 (4)
N1—H1A···O20.982.093.042 (3)163
Symmetry code: (vii) y, x, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O1i0.861 (12)1.589 (14)2.445 (2)172 (4)
N1—H1A···O20.982.093.042 (3)163
Symmetry code: (i) y, x, z+1.
 

Acknowledgements

The authors thank Professor Jesper Bendix for help with the graphics for the Scheme.

References

First citationArdon, M., Bino, A. & Michelsen, K. (1987). J. Am. Chem. Soc. 109, 1986–1990.  CrossRef CAS Google Scholar
First citationBourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59–75.  Web of Science CrossRef IUCr Journals Google Scholar
First citationBruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2014). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationParsons, S. & Flack, H. (2004). Acta Cryst. A60, s61.  CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

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