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Acta Cryst. (2007). E63, m2336    [ doi:10.1107/S1600536807039347 ]

Bis(2-aminopyrimidin-1-ium) dichromate(VI)

L. Sieron

Abstract top

The asymmetric unit of the title salt, (C4H6N3)2[Cr2O7], consists of two 2-aminopyrimidinium cations and one dichromate dianion linked together by N-H...O hydrogen bonds to form a ribbon structure lying parallel to the (013) plane and running along the a axis. Pairs of symmetry-related cations are connected into centrosymmetric dimers via N-H...N hydrogen bonds, forming eight-membered R22(8) rings.

Comment top

The title compound, (I), has been synthetized and investigated as a continuation of the structural study on hydrogen bonding in N-heterocyclic dichromate salts (Sieroń, 2007). In (I), the asymmetric unit is composed of two monoprotonated 2-aminopyrimidinium cations and one dichromate dianion (Fig. 1). The bond lengths and angles are within normal ranges (Allen et al., 1987). In the crystal structure, pairs of symmetry-related cations are connected into centrosymmetric dimers via N–H···N hydrogen bonds, forming eight-membered rings described by the R22(8) graph-set motif (Etter et al., 1990). Cations and anions are linked together by N–H···O hydrogen bonds, forming a ribbon structure lying parallel to the (013) plane and running along the a axis (Fig. 2). The hydrogen-bond arrangements around the two independent cations are not identical. One of the H atoms of one 2-aminopyrimidinium ion is engaged in a bifurcated unsymmetrical hydrogen bond [N22···O2v = 3.042 (2) and N22···O3ii = 3.144 (2) Å] to two dichromate O atoms. A bifurcation is confirmed by the sums of angles about atom H221, which is 356° (Jeffrey & Saenger, 1991). The corresponding H121 atom is involved only in one hydrogen-bond [N12···O5iii = 2.930 (2) Å]. A three-dimensional network is built up via N–H···O hydrogen bonds, together with weak C–H···O interactions.

Related literature top

For related literature, see: Allen et al. (1987); Etter et al. (1990); Jeffrey & Saenger (1991); Sieroń (2007).

Experimental top

The title compound was prepared by dissolving 2-aminopirimidine (1 mmol) and chromic anhydride (1 mmol) in hot water (25 ml). The resulting solid was recrystallized from water.

Refinement top

All H atoms were initially located in a difference Fourier map. N-bonded hydrogen atoms were refined isotropically. Remaining H atoms were positioned geometrically and refined using a riding model, with C–H = 0.93 Å and with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2003); 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 top
[Figure 1] Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 40% probability level.
[Figure 2] Fig. 2. A packing view of (I), showing a ribbon of hydrogen-bonded (dashed lines) cations and anions running along the a axis.
Bis(2-aminopyrimidin-1-ium) dichromate(VI) top
Crystal data top
(C4H6N3)2[Cr2O7]Z = 2
Mr = 408.24F000 = 412
Triclinic, P1Dx = 1.872 Mg m−3
Hall symbol: -P 1Mo Kα radiation
λ = 0.71073 Å
a = 5.4576 (2) ÅCell parameters from 7381 reflections
b = 7.6077 (2) Åθ = 2.9–27.9º
c = 18.684 (1) ŵ = 1.55 mm−1
α = 99.429 (1)ºT = 293 K
β = 91.277 (1)ºPrism, orange
γ = 108.319 (2)º0.35 × 0.20 × 0.10 mm
V = 724.23 (5) Å3
Data collection top
Bruker SMART APEX II CCD
diffractometer		3308 independent reflections
Radiation source: fine focus sealed Siemens Mo tube3215 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.015
T = 293 Kθmax = 27.5º
ω scansθmin = 1.1º
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		h = −7→7
Tmin = 0.699, Tmax = 0.861k = −9→9
18234 measured reflectionsl = −24→24
Refinement top
Refinement on F2Secondary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.023H atoms treated by a mixture of
independent and constrained refinement
wR(F2) = 0.070  w = 1/[σ2(Fo2) + (0.0389P)2 + 0.382P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
3308 reflectionsΔρmax = 0.34 e Å−3
232 parametersΔρmin = −0.34 e Å−3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
(C4H6N3)2[Cr2O7]γ = 108.319 (2)º
Mr = 408.24V = 724.23 (5) Å3
Triclinic, P1Z = 2
a = 5.4576 (2) ÅMo Kα
b = 7.6077 (2) ŵ = 1.55 mm−1
c = 18.684 (1) ÅT = 293 K
α = 99.429 (1)º0.35 × 0.20 × 0.10 mm
β = 91.277 (1)º
Data collection top
Bruker SMART APEX II CCD
diffractometer		3308 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)		3215 reflections with I > 2σ(I)
Tmin = 0.699, Tmax = 0.861Rint = 0.015
18234 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.023232 parameters
wR(F2) = 0.070H atoms treated by a mixture of
independent and constrained refinement
S = 1.06Δρmax = 0.34 e Å−3
3308 reflectionsΔρmin = −0.34 e Å−3
Special details top

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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
N110.0915 (3)0.0379 (2)0.14285 (7)0.0307 (4)
N120.3540 (3)−0.1153 (2)0.08361 (10)0.0403 (5)
N130.2962 (3)0.1365 (2)0.04052 (7)0.0288 (4)
C120.2490 (3)0.0192 (2)0.08896 (8)0.0269 (4)
C140.1811 (3)0.2672 (2)0.04731 (9)0.0326 (5)
C150.0130 (3)0.2883 (3)0.10054 (9)0.0362 (5)
C16−0.0280 (3)0.1690 (3)0.14863 (9)0.0351 (5)
N210.4818 (3)0.8505 (2)0.36313 (7)0.0309 (4)
N220.8983 (3)1.0428 (2)0.40391 (9)0.0415 (5)
N230.6664 (3)0.8431 (2)0.47701 (7)0.0318 (4)
C220.6843 (3)0.9118 (2)0.41445 (8)0.0283 (4)
C240.4469 (4)0.7125 (3)0.48464 (9)0.0366 (5)
C250.2358 (4)0.6438 (3)0.43309 (10)0.0395 (5)
C260.2601 (3)0.7179 (3)0.37136 (9)0.0347 (5)
Cr10.51287 (5)0.31598 (3)0.29255 (1)0.0250 (1)
Cr20.63801 (5)0.63913 (3)0.19279 (1)0.0249 (1)
O10.6767 (3)0.4541 (2)0.36377 (7)0.0514 (5)
O20.2111 (3)0.2848 (2)0.30192 (8)0.0485 (4)
O30.5676 (3)0.1161 (2)0.27901 (8)0.0521 (5)
O40.7031 (3)0.63515 (19)0.10909 (7)0.0432 (4)
O50.3696 (2)0.68446 (19)0.20400 (7)0.0380 (4)
O60.8691 (2)0.80393 (18)0.24414 (7)0.0376 (4)
O70.6073 (3)0.41487 (17)0.21384 (7)0.0381 (4)
H110.072 (5)−0.024 (3)0.1705 (13)0.045 (6)*
H140.214700.350000.014500.0390*
H15−0.067400.380000.102900.0430*
H16−0.138000.177600.185400.0420*
H1210.329 (5)−0.186 (4)0.1107 (15)0.054 (7)*
H1220.449 (5)−0.127 (3)0.0477 (13)0.051 (7)*
H210.496 (5)0.897 (4)0.3306 (14)0.057 (8)*
H240.432600.663400.527400.0440*
H250.085200.551300.440600.0470*
H260.124600.677200.335200.0420*
H2210.910 (4)1.076 (3)0.3673 (14)0.043 (6)*
H2221.018 (5)1.079 (3)0.4351 (14)0.047 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N110.0316 (7)0.0364 (7)0.0222 (6)0.0054 (5)0.0053 (5)0.0108 (5)
N120.0470 (9)0.0463 (9)0.0401 (8)0.0250 (7)0.0122 (7)0.0221 (7)
N130.0329 (7)0.0333 (7)0.0233 (6)0.0125 (5)0.0075 (5)0.0095 (5)
C120.0257 (7)0.0318 (7)0.0228 (7)0.0077 (6)0.0009 (5)0.0067 (6)
C140.0400 (9)0.0321 (8)0.0288 (8)0.0136 (7)0.0040 (6)0.0097 (6)
C150.0392 (9)0.0384 (9)0.0341 (8)0.0193 (7)0.0041 (7)0.0016 (7)
C160.0296 (8)0.0446 (9)0.0273 (8)0.0100 (7)0.0064 (6)−0.0008 (7)
N210.0378 (7)0.0367 (7)0.0216 (6)0.0139 (6)0.0030 (5)0.0106 (5)
N220.0424 (9)0.0463 (9)0.0289 (8)0.0006 (7)0.0006 (7)0.0154 (7)
N230.0391 (7)0.0337 (7)0.0225 (6)0.0101 (6)0.0005 (5)0.0082 (5)
C220.0352 (8)0.0293 (7)0.0217 (7)0.0116 (6)0.0035 (6)0.0054 (6)
C240.0451 (9)0.0389 (9)0.0274 (8)0.0116 (7)0.0058 (7)0.0138 (7)
C250.0359 (9)0.0431 (10)0.0358 (9)0.0046 (7)0.0063 (7)0.0124 (7)
C260.0322 (8)0.0413 (9)0.0305 (8)0.0123 (7)0.0007 (6)0.0056 (7)
Cr10.0286 (1)0.0253 (1)0.0221 (1)0.0073 (1)0.0059 (1)0.0092 (1)
Cr20.0336 (1)0.0248 (1)0.0210 (1)0.0124 (1)0.0071 (1)0.0105 (1)
O10.0426 (7)0.0661 (10)0.0323 (7)0.0037 (7)−0.0022 (5)0.0005 (6)
O20.0304 (6)0.0633 (9)0.0449 (8)0.0080 (6)0.0087 (5)0.0039 (7)
O30.0810 (11)0.0379 (7)0.0548 (8)0.0317 (7)0.0293 (8)0.0286 (6)
O40.0676 (9)0.0423 (7)0.0255 (6)0.0204 (6)0.0160 (6)0.0154 (5)
O50.0359 (6)0.0434 (7)0.0406 (7)0.0184 (5)0.0059 (5)0.0128 (5)
O60.0370 (6)0.0387 (7)0.0354 (6)0.0086 (5)0.0011 (5)0.0090 (5)
O70.0600 (8)0.0315 (6)0.0334 (6)0.0223 (6)0.0186 (5)0.0186 (5)
Geometric parameters (Å, °) top
Cr1—O11.6040 (14)N21—C261.341 (3)
Cr1—O21.6063 (17)N21—H210.75 (3)
Cr1—O31.6212 (15)N22—C221.319 (2)
Cr1—O71.7739 (13)N22—H2210.76 (3)
Cr2—O41.6090 (13)N22—H2220.81 (3)
Cr2—O51.6175 (12)N23—C221.350 (2)
Cr2—O61.6251 (13)N23—C241.322 (3)
Cr2—O71.7710 (13)C14—C151.392 (2)
N11—H110.74 (2)C15—C161.353 (3)
N11—C121.357 (2)C14—H140.93
N11—C161.345 (3)C15—H150.93
N12—C121.313 (2)C16—H160.93
N12—H1210.78 (3)C24—C251.391 (3)
N12—H1220.87 (3)C25—C261.356 (3)
N13—C121.346 (2)C24—H240.93
N13—C141.325 (2)C25—H250.93
N21—C221.357 (2)C26—H260.93
O1—Cr1—O2108.35 (8)C22—N22—H221118.8 (17)
O1—Cr1—O3111.84 (8)N11—C12—N13120.44 (15)
O1—Cr1—O7110.24 (7)N12—C12—N13119.79 (16)
O2—Cr1—O3110.62 (8)N11—C12—N12119.77 (15)
O2—Cr1—O7110.37 (8)N13—C14—C15124.03 (16)
O3—Cr1—O7105.43 (7)C14—C15—C16116.85 (17)
O4—Cr2—O5109.62 (8)N11—C16—C15119.48 (16)
O4—Cr2—O7107.95 (7)N13—C14—H14118
O5—Cr2—O6108.76 (7)C15—C14—H14118
O5—Cr2—O7109.96 (7)C14—C15—H15122
O6—Cr2—O7111.42 (7)C16—C15—H15122
O4—Cr2—O6109.11 (7)N11—C16—H16120
Cr1—O7—Cr2131.99 (8)C15—C16—H16120
C12—N11—C16121.72 (14)N21—C22—N23120.56 (15)
C12—N13—C14117.45 (15)N21—C22—N22119.75 (14)
C16—N11—H11119 (2)N22—C22—N23119.68 (15)
C12—N11—H11120 (2)N23—C24—C25124.39 (17)
C12—N12—H122118.0 (16)C24—C25—C26116.9 (2)
C12—N12—H121122 (2)N21—C26—C25119.19 (17)
H121—N12—H122120 (3)N23—C24—H24118
C22—N21—C26122.00 (14)C25—C24—H24118
C22—N23—C24116.98 (15)C26—C25—H25122
C26—N21—H21121 (2)C24—C25—H25122
C22—N21—H21117 (2)C25—C26—H26120
C22—N22—H222119.0 (17)N21—C26—H26120
H221—N22—H222122 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N11—H11···O6i0.74 (2)2.14 (2)2.841 (2)158 (3)
N21—H21···O3ii0.75 (3)2.00 (3)2.693 (2)155 (3)
N12—H121···O5iii0.78 (3)2.18 (3)2.930 (2)162 (3)
N12—H122···N13iv0.87 (3)2.19 (3)3.053 (2)176 (2)
N22—H221···O2v0.76 (3)2.41 (2)3.042 (2)141 (2)
N22—H221···O3ii0.76 (3)2.59 (2)3.144 (2)131 (2)
N22—H222···N23vi0.81 (3)2.22 (3)3.030 (2)176 (2)
C14—H14···O4vii0.932.383.161 (2)142
C16—H16···O3viii0.932.403.312 (2)165
C24—H24···O1ix0.932.373.287 (2)170
C25—H25···O1viii0.932.463.085 (3)125
Symmetry codes: (i) x−1, y−1, z; (ii) x, y+1, z; (iii) x, y−1, z; (iv) −x+1, −y, −z; (v) x+1, y+1, z; (vi) −x+2, −y+2, −z+1; (vii) −x+1, −y+1, −z; (viii) x−1, y, z; (ix) −x+1, −y+1, −z+1.
Selected geometric parameters (Å, °) top
Cr1—O11.6040 (14)N11—C161.345 (3)
Cr1—O21.6063 (17)N12—C121.313 (2)
Cr1—O31.6212 (15)N13—C121.346 (2)
Cr1—O71.7739 (13)N13—C141.325 (2)
Cr2—O41.6090 (13)N21—C221.357 (2)
Cr2—O51.6175 (12)N21—C261.341 (3)
Cr2—O61.6251 (13)N22—C221.319 (2)
Cr2—O71.7710 (13)N23—C221.350 (2)
N11—C121.357 (2)N23—C241.322 (3)
O1—Cr1—O2108.35 (8)C12—N13—C14117.45 (15)
O1—Cr1—O3111.84 (8)C22—N21—C26122.00 (14)
O1—Cr1—O7110.24 (7)C22—N23—C24116.98 (15)
O2—Cr1—O3110.62 (8)N11—C12—N13120.44 (15)
O2—Cr1—O7110.37 (8)N12—C12—N13119.79 (16)
O3—Cr1—O7105.43 (7)N11—C12—N12119.77 (15)
O4—Cr2—O5109.62 (8)N13—C14—C15124.03 (16)
O4—Cr2—O7107.95 (7)N11—C16—C15119.48 (16)
O5—Cr2—O6108.76 (7)N21—C22—N23120.56 (15)
O5—Cr2—O7109.96 (7)N21—C22—N22119.75 (14)
O6—Cr2—O7111.42 (7)N22—C22—N23119.68 (15)
O4—Cr2—O6109.11 (7)N23—C24—C25124.39 (17)
Cr1—O7—Cr2131.99 (8)N21—C26—C25119.19 (17)
C12—N11—C16121.72 (14)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N11—H11···O6i0.74 (2)2.14 (2)2.841 (2)158 (3)
N21—H21···O3ii0.75 (3)2.00 (3)2.693 (2)155 (3)
N12—H121···O5iii0.78 (3)2.18 (3)2.930 (2)162 (3)
N12—H122···N13iv0.87 (3)2.19 (3)3.053 (2)176 (2)
N22—H221···O2v0.76 (3)2.41 (2)3.042 (2)141 (2)
N22—H221···O3ii0.76 (3)2.59 (2)3.144 (2)131 (2)
N22—H222···N23vi0.81 (3)2.22 (3)3.030 (2)176 (2)
C14—H14···O4vii0.932.383.161 (2)142
C16—H16···O3viii0.932.403.312 (2)165
C24—H24···O1ix0.932.373.287 (2)170
C25—H25···O1viii0.932.463.085 (3)125
Symmetry codes: (i) x−1, y−1, z; (ii) x, y+1, z; (iii) x, y−1, z; (iv) −x+1, −y, −z; (v) x+1, y+1, z; (vi) −x+2, −y+2, −z+1; (vii) −x+1, −y+1, −z; (viii) x−1, y, z; (ix) −x+1, −y+1, −z+1.
Acknowledgements top

(no acknowledgements)

references
References top

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