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Guanidinium chloro­chromate

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bDepartment of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103, India
*Correspondence e-mail: hkfun@usm.my

(Received 21 January 2010; accepted 21 January 2010; online 27 January 2010)

In the title compound, guanidinium chloridotrioxidochrom­ate(VI), (CH6N3)[CrClO3], both the cation and anion are generated by crystallographic mirror symmetry, with one O and one N atom and the Cr, Cl and C atoms lying on the mirror plane. The bond lengths in the guanidinium cation are inter­mediate between normal C—N and C=N bond lengths, indicating significant delocalization in this species. In the crystal structure, inter­molecular N—H⋯Cl inter­actions generate R21(6) ring motifs. These ring motifs are further inter­connected by inter­molecular N—H⋯O hydrogen bonds into infinite chains along [010].

Related literature

For background to chlorido­chromates in organic synthesis, see: Ghammaamy & Maza­reey (2005[Ghammaamy, S. & Mazareey, M. (2005). J. Serb. Chem. Soc. 70, 687-693.]). For bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). For graph-set descriptions of hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For related structures, see: Al-Dajani et al. (2009[Al-Dajani, M. T. M., Abdallah, H. H., Mohamed, N., Goh, J. H. & Fun, H.-K. (2009). Acta Cryst. E65, o2508-o2509.]); Lorenzo Luis et al. (1996[Lorenzo Luis, P. A., Martin-Zarza, P., Gili, P., Ruiz-Pérez, C., Hernández-Molina, M. & Solans, X. (1996). Acta Cryst. C52, 1441-1448.]). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]).

[Scheme 1]

Experimental

Crystal data
  • (CH6N3)[CrClO3]

  • Mr = 195.54

  • Orthorhombic, P n m a

  • a = 5.9708 (2) Å

  • b = 7.5302 (2) Å

  • c = 14.7085 (4) Å

  • V = 661.31 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 2.07 mm−1

  • T = 100 K

  • 0.85 × 0.20 × 0.07 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.273, Tmax = 0.875

  • 11570 measured reflections

  • 1843 independent reflections

  • 1727 reflections with I > 2σ(I)

  • Rint = 0.027

Refinement
  • R[F2 > 2σ(F2)] = 0.020

  • wR(F2) = 0.054

  • S = 1.10

  • 1843 reflections

  • 61 parameters

  • All H-atom parameters refined

  • Δρmax = 0.55 e Å−3

  • Δρmin = −0.41 e Å−3

Table 1
Selected bond lengths (Å)

Cr1—O2 1.6101 (6)
Cr1—O2 1.6183 (8)
Cr1—Cl1 2.2099 (3)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1N1⋯O2ii 0.806 (14) 2.211 (13) 2.9984 (9) 165.7 (12)
N2—H1N2⋯O1iii 0.817 (14) 2.192 (14) 2.9702 (8) 159.4 (13)
N2—H2N2⋯Cl1 0.812 (13) 2.753 (13) 3.5075 (8) 155.5 (13)
Symmetry codes: (ii) -x, -y, -z+1; (iii) [-x, y-{\script{1\over 2}}, -z+1].

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Many methods and oxidizing agents for organic synthesis are known but development and modification of known reagents have only been studied in recent years, e.g. tributylammonium chlorochromate (Ghammaamy & Mazareey, 2005).

The asymmetric unit of the title compound comprises of a guanidinium cation and a chlorochromate anion (Fig. 1). Both of the cation and anion lie on a crystallographic mirror plane and contain one-half molecule [symmetry code of atoms labelled with suffix A: x, -y+1/2, z]. The coordination geometry formed by three O atoms and a Cl atom around the Cr atom is distorted tetrahedral, as indicated by the O1—Cr1—Cl1 and O2—Cr1—O2A angles of 106.21 (3) and 112.06 (4)° respectively. The C1–N1 and C1–N2 bond lengths in the propeller-shaped guanidinium cation are almost equal [1.3310 (14) and 1.3289 (8) Å respectively], indicating that the usual model of electron dislocalization in this moiety (Allen et al., 1987). The bond lengths and angles are comparable to closely related guanidinium (Al-Dajani et al., 2009) and chlorochromate (Lorenzo Luis et al., 1996) structures.

In the crystal structure (Fig. 2), all guanidinium-H atoms participate in intermolecular hydrogen bonds. Intermolecular N2—H2N2···Cl1 interactions (Table 1) form bifurcated acceptor hydrogen bonds which generate R12(6) ring motifs (Bernstein et al., 1995). These ring motifs are further interconnected into one-dimensional infinite chain along the [010] direction by intermolecular N1—H1N1···O2 and N2—H1N2···O1 hydrogen bonds (Table 1).

Related literature top

For background to chlorochromates in organic synthesis, see: Ghammaamy & Mazareey (2005). For bond-length data, see: Allen et al. (1987). For graph-set descriptions of hydrogen-bond motifs, see : Bernstein et al. (1995). For related structures, see: Al-Dajani et al. (2009); Lorenzo Luis et al. (1996). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental top

The new oxidizing reagent, guanidinium chlorochromate (GCC) was prepared by treatment of equivalent amounts of guanidinium hydrochloride and chromium trioxide in water at 273 K by stirring with a glass rod with instantaneous formation of yellow blocks of (I).

Refinement top

All the H atoms were located from difference Fourier map and allowed to refine freely [Range of N—H = 0.805 (14) – 0.818 (14) Å].

Structure description top

Many methods and oxidizing agents for organic synthesis are known but development and modification of known reagents have only been studied in recent years, e.g. tributylammonium chlorochromate (Ghammaamy & Mazareey, 2005).

The asymmetric unit of the title compound comprises of a guanidinium cation and a chlorochromate anion (Fig. 1). Both of the cation and anion lie on a crystallographic mirror plane and contain one-half molecule [symmetry code of atoms labelled with suffix A: x, -y+1/2, z]. The coordination geometry formed by three O atoms and a Cl atom around the Cr atom is distorted tetrahedral, as indicated by the O1—Cr1—Cl1 and O2—Cr1—O2A angles of 106.21 (3) and 112.06 (4)° respectively. The C1–N1 and C1–N2 bond lengths in the propeller-shaped guanidinium cation are almost equal [1.3310 (14) and 1.3289 (8) Å respectively], indicating that the usual model of electron dislocalization in this moiety (Allen et al., 1987). The bond lengths and angles are comparable to closely related guanidinium (Al-Dajani et al., 2009) and chlorochromate (Lorenzo Luis et al., 1996) structures.

In the crystal structure (Fig. 2), all guanidinium-H atoms participate in intermolecular hydrogen bonds. Intermolecular N2—H2N2···Cl1 interactions (Table 1) form bifurcated acceptor hydrogen bonds which generate R12(6) ring motifs (Bernstein et al., 1995). These ring motifs are further interconnected into one-dimensional infinite chain along the [010] direction by intermolecular N1—H1N1···O2 and N2—H1N2···O1 hydrogen bonds (Table 1).

For background to chlorochromates in organic synthesis, see: Ghammaamy & Mazareey (2005). For bond-length data, see: Allen et al. (1987). For graph-set descriptions of hydrogen-bond motifs, see : Bernstein et al. (1995). For related structures, see: Al-Dajani et al. (2009); Lorenzo Luis et al. (1996). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids for non-H atoms. The suffix A corresponds to the symmetry code [x, -y+1/2, z]. Intermolecular N—H···Cl hydrogen bonds are shown as dashed lines.
[Figure 2] Fig. 2. The crystal structure of (I), viewed along the a axis, showing R12(6) ring motifs being interconnected into one-dimensional chain along the b axis. Intermolecular hydrogen bonds are shown as dashed lines.
guanidinium chloridotrioxidochromate(VI) top
Crystal data top
(CH6N3)[CrClO3]F(000) = 392
Mr = 195.54Dx = 1.964 Mg m3
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 7278 reflections
a = 5.9708 (2) Åθ = 2.8–40.1°
b = 7.5302 (2) ŵ = 2.07 mm1
c = 14.7085 (4) ÅT = 100 K
V = 661.31 (3) Å3Plate, yellow
Z = 40.85 × 0.20 × 0.07 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
1843 independent reflections
Radiation source: fine-focus sealed tube1727 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
φ and ω scansθmax = 37.5°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 810
Tmin = 0.273, Tmax = 0.875k = 1212
11570 measured reflectionsl = 2125
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.020Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.054All H-atom parameters refined
S = 1.10 w = 1/[σ2(Fo2) + (0.0252P)2 + 0.1555P]
where P = (Fo2 + 2Fc2)/3
1843 reflections(Δ/σ)max < 0.001
61 parametersΔρmax = 0.55 e Å3
0 restraintsΔρmin = 0.41 e Å3
Crystal data top
(CH6N3)[CrClO3]V = 661.31 (3) Å3
Mr = 195.54Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 5.9708 (2) ŵ = 2.07 mm1
b = 7.5302 (2) ÅT = 100 K
c = 14.7085 (4) Å0.85 × 0.20 × 0.07 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
1843 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
1727 reflections with I > 2σ(I)
Tmin = 0.273, Tmax = 0.875Rint = 0.027
11570 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0200 restraints
wR(F2) = 0.054All H-atom parameters refined
S = 1.10Δρmax = 0.55 e Å3
1843 reflectionsΔρmin = 0.41 e Å3
61 parameters
Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.

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.

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 > 2sigma(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
Cr10.38355 (3)0.25000.646530 (11)0.00989 (5)
Cl10.57743 (4)0.25000.518544 (17)0.01422 (6)
O10.12221 (13)0.25000.61735 (6)0.01476 (14)
O20.44850 (10)0.07267 (8)0.70172 (4)0.01594 (11)
N10.15734 (17)0.25000.31553 (7)0.01472 (16)
N20.11145 (12)0.09721 (9)0.39621 (5)0.01507 (12)
C10.02125 (18)0.25000.36969 (7)0.01107 (15)
H1N10.218 (2)0.1568 (19)0.3047 (8)0.024 (3)*
H1N20.060 (2)0.0026 (19)0.3789 (9)0.024 (3)*
H2N20.221 (2)0.0981 (19)0.4289 (9)0.027 (3)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cr10.01033 (8)0.00893 (7)0.01042 (7)0.0000.00080 (5)0.000
Cl10.01339 (11)0.01634 (11)0.01294 (10)0.0000.00166 (8)0.000
O10.0114 (3)0.0166 (3)0.0163 (3)0.0000.0014 (3)0.000
O20.0184 (3)0.0132 (2)0.0162 (2)0.00135 (19)0.0015 (2)0.00329 (18)
N10.0154 (4)0.0121 (3)0.0166 (4)0.0000.0047 (3)0.000
N20.0169 (3)0.0099 (2)0.0184 (3)0.0013 (2)0.0047 (2)0.0001 (2)
C10.0120 (4)0.0106 (3)0.0106 (4)0.0000.0014 (3)0.000
Geometric parameters (Å, º) top
Cr1—O21.6101 (6)N1—H1N10.805 (14)
Cr1—O2i1.6102 (6)N2—C11.3289 (8)
Cr1—O11.6183 (8)N2—H1N20.818 (14)
Cr1—Cl12.2099 (3)N2—H2N20.811 (14)
N1—C11.3310 (14)C1—N2i1.3289 (8)
O2—Cr1—O2i112.06 (4)C1—N2—H1N2120.7 (9)
O2—Cr1—O1111.47 (3)C1—N2—H2N2119.5 (10)
O2i—Cr1—O1111.47 (3)H1N2—N2—H2N2119.8 (14)
O2—Cr1—Cl1107.66 (2)N2i—C1—N2119.94 (10)
O2i—Cr1—Cl1107.66 (2)N2i—C1—N1120.02 (5)
O1—Cr1—Cl1106.21 (3)N2—C1—N1120.02 (5)
C1—N1—H1N1118.5 (9)
Symmetry code: (i) x, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O2ii0.806 (14)2.211 (13)2.9984 (9)165.7 (12)
N2—H1N2···O1iii0.817 (14)2.192 (14)2.9702 (8)159.4 (13)
N2—H2N2···Cl10.812 (13)2.753 (13)3.5075 (8)155.5 (13)
Symmetry codes: (ii) x, y, z+1; (iii) x, y1/2, z+1.

Experimental details

Crystal data
Chemical formula(CH6N3)[CrClO3]
Mr195.54
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)100
a, b, c (Å)5.9708 (2), 7.5302 (2), 14.7085 (4)
V3)661.31 (3)
Z4
Radiation typeMo Kα
µ (mm1)2.07
Crystal size (mm)0.85 × 0.20 × 0.07
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.273, 0.875
No. of measured, independent and
observed [I > 2σ(I)] reflections
11570, 1843, 1727
Rint0.027
(sin θ/λ)max1)0.856
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.020, 0.054, 1.10
No. of reflections1843
No. of parameters61
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.55, 0.41

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Selected bond lengths (Å) top
Cr1—O21.6101 (6)Cr1—Cl12.2099 (3)
Cr1—O2i1.6102 (6)
Symmetry code: (i) x, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O2ii0.806 (14)2.211 (13)2.9984 (9)165.7 (12)
N2—H1N2···O1iii0.817 (14)2.192 (14)2.9702 (8)159.4 (13)
N2—H2N2···Cl10.812 (13)2.753 (13)3.5075 (8)155.5 (13)
Symmetry codes: (ii) x, y, z+1; (iii) x, y1/2, z+1.
 

Footnotes

Thomson Reuters ResearcherID: A-3561-2009.

§Thomson Reuters ResearcherID: C-7576-2009.

Acknowledgements

HKF and JHG thank Universiti Sains Malaysia (USM) for the Research University Golden Goose grant (No. 1001/PFIZIK/811012). JHG also thanks USM for the award of a USM fellowship. SG thanks the CSIR, Government of India, for a research grant and AK is grateful to the CSIR for a fellowship.

References

First citationAl-Dajani, M. T. M., Abdallah, H. H., Mohamed, N., Goh, J. H. & Fun, H.-K. (2009). Acta Cryst. E65, o2508–o2509.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CSD CrossRef Web of Science Google Scholar
First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationGhammaamy, S. & Mazareey, M. (2005). J. Serb. Chem. Soc. 70, 687–693.  Google Scholar
First citationLorenzo Luis, P. A., Martin-Zarza, P., Gili, P., Ruiz-Pérez, C., Hernández-Molina, M. & Solans, X. (1996). Acta Cryst. C52, 1441–1448.  CSD CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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