Bis(2-amino-2-thia­zolinium) dichromate(VI)

The crystal structure of the title compound, (C₃H₇N₂S)₂-[Cr₂O₇], consists of 2-amino-2-thia­zolinium cations and discrete dichromate anions linked together by N—H...O hydrogen bonds to form a one-dimensional ribbon structure lying parallel to the (102) plane and running along the b axis. The dichromate anion is located on a twofold axis that passes through its central O atom.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.023
• wR factor = 0.071
• Data-to-parameter ratio = 15.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT128_ALERT_4_C Non-standard setting of Space group P2/c    ....    P2/n
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Cr1

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cr1         (6)       5.99

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The title compound, (I), was investigated as part of a structural study on hydrogen-bonding patterns in 2-amino-2-thiazolinium salts (Sieroń, 2007).

In (I), the asymmetric unit is composed of one 2-amino-2-thiazolinium cation and half dichromate anion (Fig. 1). The cation occupies a general position whereas the anion is located on a twofold axis. The bond lengths and angles are within normal ranges (Allen et al., 1987).

The dichromate anion links the cation via intermolecular N—H···O hydrogen bonds forming eight-membered ring with graph-set descriptor R₂²(8) (Etter et al., 1990). The other N—H···O hydrogen bond associates adjacent cations via O1 atom into C₂²(6) chains. The combination of these motifs results in the formation of a one-dimensional ribbon structure lying parallel to the (102) plane and running along the b axis, as shown in Fig. 2. The same motifs are found in bis(2-amino-2-thiazolinium) tetra-µ-formato-κ⁸O:O'-bis[(formato-κO)copper(II)] structure (Sieroń, 2007).

Related literature

For related structure, see: Sieroń (2007). For related literature, see: Allen et al. (1987); Etter et al. (1990).

S2. Experimental

The title compound was prepared by dissolving 2-amino-2-thiazoline (1 mmol) and chromic anhydride (1 mmol) in hot water (25 ml). After a few days, prism-shaped orange crystals were obtained at room temperature.

S3. Refinement

All H atoms were initially located in a difference Fourier map. C-bonded H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C–H distances of 0.97 Å and U_iso(H) = 1.2U_eq(C). Amine H atoms were refined freely.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell refinement: CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXTL (Sheldrick, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2003).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. Unlabelled atoms are related to labelled atoms by symmetry code (-x + 3/2, y, -z + 3/2). Dotted lines indicate hydrogen bonds.
	Fig. 2. A packing view of (I), showing a ribbon of hydrogen-bonded (dashed lines) cations and anions running along the b axis.

Bis(2-amino-2-thiazolinium) dichromate(VI)

Crystal data

(C3H7N2S)2[Cr2O7]	F(000) = 428
Mr = 422.35	Dx = 1.903 Mg m^−3
Monoclinic, P2/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yac	Cell parameters from 8378 reflections
a = 8.0304 (1) Å	θ = 2.5–30.0°
b = 6.5332 (1) Å	µ = 1.79 mm^−1
c = 14.1019 (2) Å	T = 298 K
β = 95.065 (2)°	Prism, orange
V = 736.96 (2) Å^3	0.60 × 0.40 × 0.25 mm
Z = 2

Data collection

Kuma KM-4 CCD diffractometer	1708 independent reflections
Radiation source: CX-Mo12x0.4-S Seifert Mo tube	1604 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
Detector resolution: 8.2356 pixels mm^-1	θmax = 27.5°, θmin = 2.8°
ω scans	h = −10→10
Absorption correction: multi-scan (Oxford Diffraction, 2007)	k = −8→8
Tmin = 0.410, Tmax = 0.636	l = −18→18
9894 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.023	w = 1/[σ^2(Fo^2) + (0.0408P)^2 + 0.3039P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.071	(Δ/σ)max = 0.001
S = 1.12	Δρmax = 0.39 e Å^−3
1708 reflections	Δρmin = −0.31 e Å^−3
109 parameters	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0186 (18)
Primary atom site location: structure-invariant direct methods

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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 (Ų)

	x	y	z	Uiso*/Ueq
S1	0.21595 (6)	−0.12790 (7)	1.02709 (4)	0.0414 (2)
N1	0.31040 (19)	0.2021 (2)	0.95161 (10)	0.0331 (4)
N2	0.3482 (3)	−0.0856 (3)	0.86045 (13)	0.0426 (5)
C1	0.30017 (19)	0.0056 (3)	0.93613 (11)	0.0294 (4)
C2	0.2114 (3)	0.1018 (3)	1.09950 (13)	0.0393 (5)
C3	0.2295 (2)	0.2811 (3)	1.03239 (13)	0.0366 (5)
Cr1	0.53421 (3)	0.42057 (4)	0.74127 (2)	0.0263 (1)
O1	0.45721 (16)	0.4958 (2)	0.83802 (9)	0.0373 (4)
O2	0.4996 (2)	0.1793 (2)	0.72715 (11)	0.0523 (5)
O3	0.75000	0.4772 (4)	0.75000	0.0558 (7)
O4	0.4462 (2)	0.5453 (3)	0.65261 (11)	0.0542 (5)
H1	0.351 (3)	0.280 (4)	0.9131 (18)	0.052 (7)*
H2A	0.10670	0.11100	1.12860	0.0470*
H2B	0.30260	0.10060	1.14940	0.0470*
H3A	0.12060	0.33720	1.01140	0.0440*
H3B	0.29690	0.38820	1.06420	0.0440*
H21	0.386 (3)	−0.014 (4)	0.8192 (17)	0.043 (6)*
H22	0.352 (3)	−0.205 (5)	0.8556 (19)	0.053 (7)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0513 (3)	0.0294 (2)	0.0450 (3)	−0.0049 (2)	0.0127 (2)	0.0094 (2)
N1	0.0397 (7)	0.0273 (7)	0.0336 (7)	−0.0038 (6)	0.0102 (6)	0.0044 (6)
N2	0.0566 (10)	0.0313 (9)	0.0418 (9)	0.0075 (7)	0.0150 (8)	0.0013 (7)
C1	0.0263 (7)	0.0287 (8)	0.0330 (7)	0.0022 (6)	0.0019 (6)	0.0053 (6)
C2	0.0429 (10)	0.0434 (10)	0.0322 (8)	−0.0022 (7)	0.0065 (7)	0.0038 (7)
C3	0.0441 (9)	0.0314 (9)	0.0350 (8)	−0.0036 (7)	0.0072 (7)	−0.0029 (7)
Cr1	0.0251 (2)	0.0267 (2)	0.0280 (2)	−0.0017 (1)	0.0076 (1)	−0.0007 (1)
O1	0.0405 (6)	0.0331 (6)	0.0409 (7)	−0.0021 (5)	0.0190 (5)	−0.0040 (5)
O2	0.0727 (10)	0.0310 (7)	0.0556 (8)	−0.0064 (7)	0.0197 (7)	−0.0111 (6)
O3	0.0263 (9)	0.0703 (14)	0.0725 (14)	0.0000	0.0148 (9)	0.0000
O4	0.0521 (9)	0.0639 (10)	0.0454 (8)	−0.0076 (7)	−0.0029 (6)	0.0207 (7)

Geometric parameters (Å, º)

Cr1—O1	1.6231 (13)	N1—H1	0.83 (3)
Cr1—O2	1.6099 (13)	N2—H21	0.83 (2)
Cr1—O3	1.7656 (6)	N2—H22	0.78 (3)
Cr1—O4	1.6033 (17)	C2—C3	1.521 (3)
S1—C1	1.7369 (17)	C2—H2B	0.97
S1—C2	1.817 (2)	C2—H2A	0.97
N1—C1	1.304 (2)	C3—H3A	0.97
N1—C3	1.455 (2)	C3—H3B	0.97
N2—C1	1.310 (3)
O1—Cr1—O2	109.03 (7)	S1—C1—N2	122.36 (16)
O1—Cr1—O3	108.80 (6)	N1—C1—N2	124.45 (17)
O1—Cr1—O4	109.10 (8)	S1—C2—C3	106.18 (13)
O2—Cr1—O3	111.81 (10)	N1—C3—C2	106.73 (15)
O2—Cr1—O4	109.99 (9)	C3—C2—H2A	110
O3—Cr1—O4	108.07 (8)	S1—C2—H2A	111
C1—S1—C2	91.65 (9)	S1—C2—H2B	110
Cr1—O3—Cr1^i	155.81 (17)	C3—C2—H2B	110
C1—N1—C3	117.04 (14)	H2A—C2—H2B	109
C3—N1—H1	121.5 (18)	N1—C3—H3A	110
C1—N1—H1	121.1 (18)	N1—C3—H3B	110
C1—N2—H21	118.0 (18)	C2—C3—H3A	110
C1—N2—H22	122.7 (19)	C2—C3—H3B	110
H21—N2—H22	119 (3)	H3A—C3—H3B	109
S1—C1—N1	113.19 (12)

Symmetry code: (i) −x+3/2, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1	0.83 (3)	2.00 (3)	2.8233 (19)	171 (2)
N2—H21···O2	0.83 (2)	2.08 (2)	2.900 (3)	174 (2)
N2—H22···O1^ii	0.78 (3)	2.15 (3)	2.897 (2)	159 (2)

Symmetry code: (ii) x, y−1, z.