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Mol­ecules of 2,4-diamino-1,3,5-triazine (guanamine), C3H5N5, are associated in the crystal structure via four independent N—H...N hydrogen bonds to form a three-dimensional framework. The hydrogen-bonding scheme involves all hydrogen donor/acceptor sites. The mol­ecular geometry of the aromatic ring conforms to C2v symmetry within experimental error.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807027407/fj2037sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807027407/fj2037Isup2.hkl
Contains datablock I

CCDC reference: 654974

Key indicators

  • Single-crystal X-ray study
  • T = 298 K
  • Mean [sigma](N-C) = 0.001 Å
  • R factor = 0.042
  • wR factor = 0.128
  • Data-to-parameter ratio = 18.1

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.29
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 0 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 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

As a part of our continuing study of crystal adducts of DNA/RNA pyrimidine bases coupled with amino-derivatives of aromatic N-heterocycles via multiple hydrogen bonds to mimic the base-pairing of nucleic acids (Portalone et al., 1999; Brunetti et al., 2000, 2002; Portalone et al., 2002; Portalone & Colapietro, 2004a,b; Portalone & Colapietro, 2006; Portalone & Colapietro, 2007a,b,c,d) we became interested in guanamine (I), as a good candidate to be associated in the crystal with pyrimidinic nucleobases.

The asymmetric unit of (I) comprises a planar molecule and is shown in Fig. 1. With regard to the aromatic ring, the bond lengths and angles are normal and conform within experimental error to C2v symmetry (Table 1). The H-bonding scheme involves all H atoms of the NH2 groups (Fig. 2) and consists entirely of N—H··· N intermolecular interactions (Table 2). These interactions delineate patterns in which rings are the most prominent features. Besides the intermolecular N—H··· N hydrogen bonds, two small rings of descriptor R22(8) are formed by centrosymmetric molecules. Infinite C22(6) chains are then generated by the 21 screw axis running along the b direction,

Related literature top

For related literature describing crystal adducts of DNA/RNA pyrimidine bases coupled with amino derivatives of aromatic N-heterocycles via multiple hydrogen bonds to mimic the base-pairing of nucleic acids, see: Portalone et al. (1999, 2002); Brunetti et al. (2000, 2002); Portalone & Colapietro (2004a,b, 2006, 2007a,b,c,d).

Experimental top

Guanamine was purchased from Sigma Aldrich (99% purity). and used as obtained. Crystals of guanamine were grown from a hot water solution (0.25 mmol in ca 10 ml) by slow evaporation of the solvent.

Refinement top

All H atoms were found in a difference Fourier map. Positional and isotropic displacement parameters of all H atoms were independently refined (C—H = 0.972 (13) Å, N—H = 0.851 (16)–0.903 (18) Å).

Structure description top

As a part of our continuing study of crystal adducts of DNA/RNA pyrimidine bases coupled with amino-derivatives of aromatic N-heterocycles via multiple hydrogen bonds to mimic the base-pairing of nucleic acids (Portalone et al., 1999; Brunetti et al., 2000, 2002; Portalone et al., 2002; Portalone & Colapietro, 2004a,b; Portalone & Colapietro, 2006; Portalone & Colapietro, 2007a,b,c,d) we became interested in guanamine (I), as a good candidate to be associated in the crystal with pyrimidinic nucleobases.

The asymmetric unit of (I) comprises a planar molecule and is shown in Fig. 1. With regard to the aromatic ring, the bond lengths and angles are normal and conform within experimental error to C2v symmetry (Table 1). The H-bonding scheme involves all H atoms of the NH2 groups (Fig. 2) and consists entirely of N—H··· N intermolecular interactions (Table 2). These interactions delineate patterns in which rings are the most prominent features. Besides the intermolecular N—H··· N hydrogen bonds, two small rings of descriptor R22(8) are formed by centrosymmetric molecules. Infinite C22(6) chains are then generated by the 21 screw axis running along the b direction,

For related literature describing crystal adducts of DNA/RNA pyrimidine bases coupled with amino derivatives of aromatic N-heterocycles via multiple hydrogen bonds to mimic the base-pairing of nucleic acids, see: Portalone et al. (1999, 2002); Brunetti et al. (2000, 2002); Portalone & Colapietro (2004a,b, 2006, 2007a,b,c,d).

Computing details top

Data collection: XCS (Colapietro et al., 1992); cell refinement: XCS; data reduction: XCS; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The crystallographic asymmetric unit in guanamine, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of guanamine viewed down the crystallographic b axis. For the sake of clarity, only H atoms involved in hydrogen bonding are shown as small spheres of arbitrary radii. Displacements ellipsoids are drawn at the 50% probability level. Hydrogen bonding is indicated by dashed lines.
2,4-diamino-1,3,5-triazine top
Crystal data top
C3H5N5F(000) = 232
Mr = 111.12Dx = 1.575 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybcCell parameters from 87 reflections
a = 9.8631 (9) Åθ = 21–27°
b = 3.7180 (3) ŵ = 0.12 mm1
c = 12.9609 (9) ÅT = 298 K
β = 99.643 (9)°Tablet, colourless
V = 468.57 (7) Å30.15 × 0.12 × 0.10 mm
Z = 4
Data collection top
Huber CS four-circle
diffractometer
Rint = 0.026
Radiation source: X-Ray tubeθmax = 32.5°, θmin = 2.1°
Graphite monochromatorh = 014
ω scansk = 05
2088 measured reflectionsl = 1919
1684 independent reflections3 standard reflections every 97 reflections
1450 reflections with I > 2σ(I) intensity decay: 1%
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128All H-atom parameters refined
S = 1.07 w = 1/[σ2(Fo2) + (0.0865P)2 + 0.0407P]
where P = (Fo2 + 2Fc2)/3
1684 reflections(Δ/σ)max = 0.001
93 parametersΔρmax = 0.35 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C3H5N5V = 468.57 (7) Å3
Mr = 111.12Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.8631 (9) ŵ = 0.12 mm1
b = 3.7180 (3) ÅT = 298 K
c = 12.9609 (9) Å0.15 × 0.12 × 0.10 mm
β = 99.643 (9)°
Data collection top
Huber CS four-circle
diffractometer
Rint = 0.026
2088 measured reflections3 standard reflections every 97 reflections
1684 independent reflections intensity decay: 1%
1450 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.128All H-atom parameters refined
S = 1.07Δρmax = 0.35 e Å3
1684 reflectionsΔρmin = 0.22 e Å3
93 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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
N10.61517 (7)0.0133 (2)0.89333 (5)0.02784 (18)
N30.79107 (7)0.0531 (2)0.78800 (5)0.02702 (18)
N50.83121 (7)0.2817 (2)0.96284 (5)0.02508 (18)
N70.99658 (8)0.3212 (2)0.85938 (6)0.03028 (19)
N80.66293 (9)0.2167 (3)1.06320 (6)0.0387 (2)
C20.66676 (8)0.0349 (3)0.80627 (6)0.02765 (19)
C40.87077 (8)0.2155 (2)0.87067 (6)0.02206 (17)
C60.70459 (8)0.1707 (2)0.97155 (6)0.02440 (18)
H20.6089 (13)0.151 (3)0.7476 (10)0.032 (3)*
H711.0272 (14)0.261 (4)0.8030 (12)0.048 (4)*
H721.0486 (19)0.421 (4)0.9162 (13)0.049 (4)*
H810.5800 (17)0.144 (4)1.0735 (12)0.043 (3)*
H820.7201 (16)0.298 (4)1.1143 (12)0.051 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0212 (3)0.0393 (4)0.0235 (3)0.0077 (3)0.0052 (2)0.0031 (2)
N30.0238 (3)0.0369 (4)0.0211 (3)0.0032 (3)0.0061 (2)0.0024 (2)
N50.0201 (3)0.0352 (4)0.0210 (3)0.0061 (2)0.0063 (2)0.0026 (2)
N70.0219 (3)0.0442 (4)0.0269 (4)0.0066 (3)0.0102 (3)0.0025 (3)
N80.0279 (4)0.0668 (6)0.0238 (4)0.0178 (4)0.0114 (3)0.0114 (3)
C20.0238 (4)0.0368 (4)0.0223 (3)0.0054 (3)0.0036 (3)0.0037 (3)
C40.0200 (3)0.0259 (3)0.0209 (3)0.0007 (2)0.0054 (2)0.0020 (2)
C60.0209 (3)0.0320 (4)0.0212 (3)0.0046 (3)0.0060 (3)0.0009 (2)
Geometric parameters (Å, º) top
N1—C21.3254 (10)N7—H710.866 (16)
N1—C61.3597 (10)N7—H720.903 (18)
N3—C21.3280 (11)N8—C61.3313 (10)
N3—C41.3596 (10)N8—H810.893 (17)
N5—C61.3378 (10)N8—H820.851 (16)
N5—C41.3401 (9)C2—H20.972 (13)
N7—C41.3329 (10)
C2—N1—C6113.55 (7)N1—C2—N3128.02 (7)
C2—N3—C4113.46 (7)N1—C2—H2117.9 (8)
C6—N5—C4115.72 (7)N3—C2—H2114.1 (8)
C4—N7—H71118.6 (10)N7—C4—N5117.34 (7)
C4—N7—H72116.3 (11)N7—C4—N3118.06 (7)
H71—N7—H72124.3 (14)N5—C4—N3124.59 (7)
C6—N8—H81121.4 (10)N8—C6—N5117.89 (7)
C6—N8—H82118.5 (11)N8—C6—N1117.51 (7)
H81—N8—H82119.7 (15)N5—C6—N1124.60 (7)
C6—N1—C2—N30.52 (15)C2—N3—C4—N50.49 (13)
C4—N3—C2—N10.82 (15)C4—N5—C6—N8177.18 (8)
C6—N5—C4—N7179.75 (7)C4—N5—C6—N12.70 (14)
C6—N5—C4—N31.13 (13)C2—N1—C6—N8177.48 (9)
C2—N3—C4—N7178.62 (8)C2—N1—C6—N52.40 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H71···N3i0.866 (16)2.549 (16)3.1811 (10)130.7 (13)
N7—H72···N5ii0.903 (18)2.113 (18)3.0106 (12)172.3 (14)
N8—H81···N1iii0.893 (17)2.123 (17)3.0150 (11)176.6 (14)
N8—H82···N3iv0.851 (16)2.310 (15)3.0962 (11)153.9 (14)
Symmetry codes: (i) x+2, y+1/2, z+3/2; (ii) x+2, y+1, z+2; (iii) x+1, y, z+2; (iv) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC3H5N5
Mr111.12
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)9.8631 (9), 3.7180 (3), 12.9609 (9)
β (°) 99.643 (9)
V3)468.57 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.15 × 0.12 × 0.10
Data collection
DiffractometerHuber CS four-circle
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2088, 1684, 1450
Rint0.026
(sin θ/λ)max1)0.756
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.128, 1.07
No. of reflections1684
No. of parameters93
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.35, 0.22

Computer programs: XCS (Colapietro et al., 1992), XCS, SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), SHELXL97.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H71···N3i0.866 (16)2.549 (16)3.1811 (10)130.7 (13)
N7—H72···N5ii0.903 (18)2.113 (18)3.0106 (12)172.3 (14)
N8—H81···N1iii0.893 (17)2.123 (17)3.0150 (11)176.6 (14)
N8—H82···N3iv0.851 (16)2.310 (15)3.0962 (11)153.9 (14)
Symmetry codes: (i) x+2, y+1/2, z+3/2; (ii) x+2, y+1, z+2; (iii) x+1, y, z+2; (iv) x, y+1/2, z+1/2.
 

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