Pyridinium trans-di­aqua­bis­[oxalato(2−)-κ2O1,O2]chromate(III) urea monosolvate

Bebga, G.; Signé, M.; Nenwa, J.; Mbarki, M.; Fokwa, B.P.T.

doi:10.1107/S1600536813026135

metal-organic compounds

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Volume 69| Part 10| October 2013| Page m567

doi:10.1107/S1600536813026135

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Pyridinium trans-diaquabis[oxalato(2−)-κ²O¹,O²]chromate(III) urea monosolvate

Gouet Bebga,^a ^* Martin Signé,^b Justin Nenwa,^b Mohammed Mbarki ^c and Boniface P. T. Fokwa ^c

^aDepartment of Chemistry, Higher Teacher Training College, University of Yaounde I, POB 47, Cameroon, ^bDepartement of Inorganic Chemistry, University of Yaounde I, POB 812 Yaounde, Cameroon, and ^cInstitut für Anorganische Chemie, RWTH Aachen, D-52056 Aachen, Germany
^*Correspondence e-mail: gouetbeb@yahoo.fr

(Received 17 September 2013; accepted 21 September 2013; online 28 September 2013)

The asymmetric unit of the title solvated molecular salt, (C₅H₆N)[Cr(C₂O₄)₂(H₂O)₂]·CO(NH₂)₂, contains half a formula unit. Each component is completed by crystallographic twofold symmetry: in the cation, one C and the N atom lie on the rotation axis; in the anion, the Cr^III ion lies on the axis; in the solvent molecule, the C and the O atom lie on the axis. The aqua ligands are in a trans disposition in the resulting CrO₆ octahedron. In the crystal, the components are linked by O—H⋯O, N—H⋯O and N—H⋯(O,O) hydrogen bonds, generating a three-dimensional network.

CCDC reference: 962597

Related literature

For molecular salts containing the [Cr(C₂O₄)₂(H₂O)₂]⁻ anion, see: Bélombé et al. (2009 ); Nenwa et al. (2010 , 2012 ); Chérif et al. (2011 ); Chérif, Zid et al. (2012 ); Chérif, Abdelhak et al. (2012 ); Dridi et al. (2013 ).

Experimental

Crystal data

(C₅H₆N)[Cr(C₂O₄)₂(H₂O)₂]·CH₄N₂O
M_r = 404.24
Monoclinic, I 2/a
a = 7.6456 (7) Å
b = 21.4096 (18) Å
c = 9.7404 (12) Å
β = 100.278 (1)°
V = 1568.8 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.80 mm⁻¹
T = 293 K
0.20 × 0.16 × 0.13 mm

Data collection

Bruker APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ) T_min = 0.851, T_max = 0.935
11770 measured reflections
2343 independent reflections
1980 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.111
S = 1.10
2343 reflections
132 parameters
5 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.56 e Å⁻³

Table 1
Selected bond lengths (Å)

Cr4—O2	1.9436 (12)
Cr4—O3	1.9762 (12)
Cr4—O1	1.9955 (14)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O4ⁱ	0.86	2.26	2.979 (3)	142
N1—H1⋯O4ⁱⁱ	0.86	2.26	2.979 (3)	142
N2—H2A⋯O4ⁱⁱⁱ	0.82 (2)	2.36 (2)	3.134 (2)	158 (3)
N2—H2B⋯O5^iv	0.79 (2)	2.08 (2)	2.847 (2)	166 (3)
O1—H1B⋯O3ⁱⁱⁱ	0.81 (2)	1.91 (2)	2.7135 (18)	174 (3)
O1—H1A⋯O6	0.81 (2)	1.79 (2)	2.5910 (16)	176 (3)
Symmetry codes: (i) -x+1, -y+1, -z; (ii) $[x+{\script{1\over 2}}, -y+1, z]$ ; (iii) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z-{\script{1\over 2}}]$ ; (iv) -x+1, -y, -z.

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010 ); software used to prepare material for publication: WinGX (Farrugia, 2012 ).

Supporting information

CCDC reference: 962597

Crystal structure: contains datablock I. DOI: 10.1107/S1600536813026135/hb7141sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813026135/hb7141Isup2.hkl

checkCIF report

Comment top

Recently, the crystal structures of some salts involving organic cations and the complex anion [Cr(C₂O₄)₂(H₂O)₂]^-, have been reported (Bélombé et al.,2009; Nenwa et al., 2010; Chérif, Zid et al., 2012; Chérif, Abdelhak et al., 2012; Nenwa, Gouet et al. 2012). We now report the structure of the title compound, with the organic cation, pyridinium, the trans-diaquabis(oxalate)chromate(III) complex anion and the urea molecule which replaces the fraction of water molecule of crystallization in the previously described structures (Chérif et al., 2011; Chérif, Abdelhak et al.,2012; Dridi et al., 2013).

The constituents of the title compound are shown in Fig.1. It appears to be the first member of salts with general formula A_m[M(C₂O₄)₂(H₂O)₂].xOC(NH₂)₂; where A = organic cation, M = metal(II) or metal(III), m = 1 or 2 and x ≥ 0. The asymmetric unit is formed by a pyridinium cation, a [Cr(C₂O₄)₂(H₂O)₂]^– anionic complex in trans-aqua configuration and one urea molecule. The chromium (III) ion lies on a twofold axis and is six-coordinated in a distorted octahedral geometry defined by four O atoms from two chelating bidendate oxalate anions in the equatorial plane and by two O atoms from two apical aqua ligands. The equatorial Cr–O_(oxalate) distances, 1.9435 (13) Å and 1.9762 (13) Å, are slightly shorter than the axial Cr–O_(water) one [1.9955 (15) Å]. These bond distances are similar to those observed in homologous complex salts (Bélombé et al., 2009; Nenwa et al., 2010; Chérif et al., 2011; Chérif, Abdelhak et al., 2012; Chérif, Abdelhak et al., 2012; Nenwa et al., 2012; Dridi et al., 2013).

The crystal structure can be described by a characteristic layered arrangement of the pyridinium cation, (C₅H₆N)⁺, the complex anion, [Cr(C₂O₄)₂(H₂O)₂]^-, and the urea molecule (Fig. 2). O–H···O and N–H···O hydrogen bonding interactions link the components (Fig.3).

Related literature top

For molecular salts containing the [Cr(C₂O₄)₂(H₂O)₂]^- anion, see: Bélombé et al. (2009); Nenwa et al. (2010, 2012); Chérif et al. (2011); Chérif, Zid et al. (2012); Chérif, Abdelhak et al. (2012); Dridi et al. (2013).

Experimental top

1 mmol (267 mg) of CrCl₃·6H₂O was dissolved in 50 ml of water. The green filtered solution was stirred at 323 K, 2 mmol (253 mg) of oxalic acid, 1 mmol (79.1 mg) of pyridine and 2 mmol (121 mg) of urea were added in successive small portions and stirred for 2 h. The resulting violet solution was left at room temperature; violet prisms were obtained after one week of slow evaporation.

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top

	Fig. 1. Molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. Packing diagram of the title compound, viewed along the a axis, showing its layered structure.
	Fig. 3. Interconnection of the constituents of the title compound into a three-dimensional network. Hydrogen bonds are highlighted with dashed lines.

Pyridinium trans-diaquabis[oxalato(2-)-κ²O¹,O²]chromate(III) urea monosolvate top

Crystal data top

(C₅H₆N)[Cr(C₂O₄)₂(H₂O)₂]·CH₄N₂O	Z = 4
M_r = 404.24	F(000) = 828
Monoclinic, I2/a	D_x = 1.712 Mg m⁻³
Hall symbol: -I 2ya	Mo Kα radiation, λ = 0.71073 Å
a = 7.6456 (7) Å	µ = 0.80 mm⁻¹
b = 21.4096 (18) Å	T = 293 K
c = 9.7404 (12) Å	Prism, violet
β = 100.278 (1)°	0.20 × 0.16 × 0.13 mm
V = 1568.8 (3) Å³

Data collection top

Bruker APEX CCD diffractometer	2343 independent reflections
Radiation source: fine-focus sealed tube	1980 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
ω scans	θ_max = 30.9°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −10→10
T_min = 0.851, T_max = 0.935	k = −30→30
11770 measured reflections	l = −13→14

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ²(F_o²) + (0.0515P)² + 1.3542P] where P = (F_o² + 2F_c²)/3
2343 reflections	(Δ/σ)_max < 0.001
132 parameters	Δρ_max = 0.30 e Å⁻³
5 restraints	Δρ_min = −0.56 e Å⁻³

Crystal data top

(C₅H₆N)[Cr(C₂O₄)₂(H₂O)₂]·CH₄N₂O	V = 1568.8 (3) Å³
M_r = 404.24	Z = 4
Monoclinic, I2/a	Mo Kα radiation
a = 7.6456 (7) Å	µ = 0.80 mm⁻¹
b = 21.4096 (18) Å	T = 293 K
c = 9.7404 (12) Å	0.20 × 0.16 × 0.13 mm
β = 100.278 (1)°

Data collection top

Bruker APEX CCD diffractometer	2343 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2004)	1980 reflections with I > 2σ(I)
T_min = 0.851, T_max = 0.935	R_int = 0.032
11770 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	5 restraints
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	Δρ_max = 0.30 e Å⁻³
2343 reflections	Δρ_min = −0.56 e Å⁻³
132 parameters

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

	x	y	z	U_iso*/U_eq
Cr4	0.2500	0.223340 (17)	0.0000	0.02410 (13)
O1	0.45417 (19)	0.22672 (6)	−0.10198 (14)	0.0315 (3)
O2	0.35892 (18)	0.15558 (6)	0.11799 (13)	0.0324 (3)
O3	0.14209 (17)	0.29281 (6)	−0.11952 (12)	0.0288 (3)
O4	0.1309 (2)	0.39675 (7)	−0.12681 (15)	0.0436 (4)
O5	0.3604 (2)	0.05182 (7)	0.13176 (16)	0.0498 (4)
C1	0.1842 (2)	0.34777 (8)	−0.07105 (17)	0.0285 (3)
C2	0.3134 (3)	0.10049 (8)	0.07197 (18)	0.0319 (4)
N1	0.7500	0.48039 (15)	0.0000	0.0622 (8)
H1	0.7500	0.5206	0.0000	0.075*
C3	0.8444 (3)	0.38759 (15)	0.1108 (3)	0.0576 (7)
H3	0.9099	0.3668	0.1868	0.069*
C4	0.7500	0.35421 (17)	0.0000	0.0527 (8)
H4	0.7500	0.3108	0.0000	0.063*
C5	0.8402 (4)	0.45021 (15)	0.1071 (3)	0.0594 (7)
H5	0.9023	0.4727	0.1819	0.071*
O6	0.7500	0.17120 (9)	0.0000	0.0388 (4)
N2	0.6418 (3)	0.08022 (9)	−0.0971 (2)	0.0447 (4)
C6	0.7500	0.11234 (13)	0.0000	0.0326 (5)
H2A	0.584 (3)	0.0960 (12)	−0.168 (2)	0.055 (8)*
H2B	0.649 (4)	0.0435 (8)	−0.092 (3)	0.061 (9)*
H1B	0.434 (3)	0.2215 (11)	−0.1855 (17)	0.049 (8)*
H1A	0.544 (3)	0.2077 (11)	−0.071 (2)	0.053 (8)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cr4	0.0280 (2)	0.0240 (2)	0.01765 (18)	0.000	−0.00312 (13)	0.000
O1	0.0307 (7)	0.0389 (7)	0.0229 (6)	0.0050 (5)	−0.0004 (5)	−0.0009 (5)
O2	0.0385 (7)	0.0280 (6)	0.0259 (6)	0.0010 (5)	−0.0071 (5)	0.0020 (5)
O3	0.0334 (6)	0.0290 (6)	0.0213 (5)	0.0013 (5)	−0.0020 (5)	0.0010 (4)
O4	0.0565 (9)	0.0310 (7)	0.0391 (8)	0.0071 (6)	−0.0026 (7)	0.0067 (6)
O5	0.0713 (11)	0.0278 (7)	0.0433 (8)	0.0053 (7)	−0.0084 (8)	0.0046 (6)
C1	0.0313 (9)	0.0293 (8)	0.0245 (8)	0.0015 (6)	0.0043 (6)	0.0013 (6)
C2	0.0358 (9)	0.0303 (8)	0.0272 (8)	0.0024 (7)	−0.0014 (7)	0.0024 (6)
N1	0.069 (2)	0.0486 (17)	0.071 (2)	0.000	0.0156 (17)	0.000
C3	0.0445 (13)	0.0814 (19)	0.0409 (12)	0.0074 (12)	−0.0084 (10)	0.0166 (12)
C4	0.0477 (19)	0.0471 (18)	0.062 (2)	0.000	0.0057 (16)	0.000
C5	0.0567 (15)	0.0726 (18)	0.0456 (13)	−0.0166 (13)	0.0001 (11)	−0.0139 (12)
O6	0.0303 (9)	0.0295 (9)	0.0514 (12)	0.000	−0.0067 (8)	0.000
N2	0.0520 (11)	0.0336 (9)	0.0434 (10)	−0.0022 (8)	−0.0052 (8)	−0.0043 (8)
C6	0.0291 (12)	0.0338 (12)	0.0346 (12)	0.000	0.0052 (10)	0.000

Geometric parameters (Å, º) top

Cr4—O2ⁱ	1.9436 (12)	N1—C5ⁱⁱ	1.313 (3)
Cr4—O2	1.9436 (12)	N1—C5	1.313 (3)
Cr4—O3ⁱ	1.9762 (12)	N1—H1	0.8600
Cr4—O3	1.9762 (12)	C3—C5	1.341 (4)
Cr4—O1	1.9955 (14)	C3—C4	1.385 (3)
Cr4—O1ⁱ	1.9955 (14)	C3—H3	0.9300
O1—H1B	0.808 (16)	C4—C3ⁱⁱ	1.385 (3)
O1—H1A	0.808 (16)	C4—H4	0.9300
O2—C2	1.287 (2)	C5—H5	0.9300
O3—C1	1.287 (2)	O6—C6	1.260 (3)
O4—C1	1.217 (2)	N2—C6	1.331 (2)
O5—C2	1.216 (2)	N2—H2A	0.821 (17)
C1—C1ⁱ	1.559 (3)	N2—H2B	0.788 (17)
C2—C2ⁱ	1.556 (3)	C6—N2ⁱⁱ	1.331 (2)

O2ⁱ—Cr4—O2	83.43 (7)	O3—C1—C1ⁱ	113.91 (9)
O2ⁱ—Cr4—O3ⁱ	179.29 (5)	O5—C2—O2	125.43 (17)
O2—Cr4—O3ⁱ	97.10 (5)	O5—C2—C2ⁱ	120.99 (11)
O2ⁱ—Cr4—O3	97.10 (5)	O2—C2—C2ⁱ	113.59 (9)
O2—Cr4—O3	179.29 (5)	C5ⁱⁱ—N1—C5	121.0 (4)
O3ⁱ—Cr4—O3	82.36 (7)	C5ⁱⁱ—N1—H1	119.5
O2ⁱ—Cr4—O1	91.34 (6)	C5—N1—H1	119.5
O2—Cr4—O1	91.76 (6)	C5—C3—C4	119.2 (2)
O3ⁱ—Cr4—O1	89.11 (5)	C5—C3—H3	120.4
O3—Cr4—O1	87.76 (5)	C4—C3—H3	120.4
O2ⁱ—Cr4—O1ⁱ	91.76 (6)	C3—C4—C3ⁱⁱ	117.9 (4)
O2—Cr4—O1ⁱ	91.34 (6)	C3—C4—H4	121.1
O3ⁱ—Cr4—O1ⁱ	87.76 (5)	C3ⁱⁱ—C4—H4	121.1
O3—Cr4—O1ⁱ	89.11 (5)	N1—C5—C3	121.3 (3)
O1—Cr4—O1ⁱ	175.84 (8)	N1—C5—H5	119.3
Cr4—O1—H1B	117.8 (19)	C3—C5—H5	119.3
Cr4—O1—H1A	119.1 (19)	C6—N2—H2A	124 (2)
H1B—O1—H1A	108 (2)	C6—N2—H2B	116 (2)
C2—O2—Cr4	114.66 (11)	H2A—N2—H2B	119 (3)
C1—O3—Cr4	114.90 (10)	O6—C6—N2	121.10 (13)
O4—C1—O3	125.58 (16)	O6—C6—N2ⁱⁱ	121.10 (13)
O4—C1—C1ⁱ	120.51 (11)	N2—C6—N2ⁱⁱ	117.8 (3)

Symmetry codes: (i) −x+1/2, y, −z; (ii) −x+3/2, y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O4ⁱⁱⁱ	0.86	2.26	2.979 (3)	142
N1—H1···O4^iv	0.86	2.26	2.979 (3)	142
N2—H2A···O4^v	0.82 (2)	2.36 (2)	3.134 (2)	158 (3)
N2—H2B···O5^vi	0.79 (2)	2.08 (2)	2.847 (2)	166 (3)
O1—H1B···O3^v	0.81 (2)	1.91 (2)	2.7135 (18)	174 (3)
O1—H1A···O6	0.81 (2)	1.79 (2)	2.5910 (16)	176 (3)

Symmetry codes: (iii) −x+1, −y+1, −z; (iv) x+1/2, −y+1, z; (v) −x+1/2, −y+1/2, −z−1/2; (vi) −x+1, −y, −z.

Selected bond lengths (Å) top

Cr4—O2	1.9436 (12)	Cr4—O1	1.9955 (14)
Cr4—O3	1.9762 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O4ⁱ	0.86	2.26	2.979 (3)	142
N1—H1···O4ⁱⁱ	0.86	2.26	2.979 (3)	142
N2—H2A···O4ⁱⁱⁱ	0.821 (17)	2.357 (19)	3.134 (2)	158 (3)
N2—H2B···O5^iv	0.788 (17)	2.077 (19)	2.847 (2)	166 (3)
O1—H1B···O3ⁱⁱⁱ	0.808 (16)	1.909 (16)	2.7135 (18)	174 (3)
O1—H1A···O6	0.808 (16)	1.785 (16)	2.5910 (16)	176 (3)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) x+1/2, −y+1, z; (iii) −x+1/2, −y+1/2, −z−1/2; (iv) −x+1, −y, −z.

Acknowledgements

The authors thank Tobias Storp (RWTH Aachen) for his technical support during the X-ray experiments.

References

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