organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Melaminium iodide monohydrate

aOrdered Matter Science Research Center, College of Chemistry and Chemical, Engineering, Southeast University, Nanjing 211189, People's Republic of China
*Correspondence e-mail: zmmzyahfdzg@126.com

(Received 25 April 2010; accepted 14 May 2010; online 22 May 2010)

In the title melaminium salt, 2,4,6-triamino-1,3,5-triazin-1-ium iodide monohydrate, C3H7N6+·I·H2O, the components are linked via N—H⋯O, N—H⋯N, O—H⋯I and N—H⋯I hydrogen bonds. All of the H atoms of the melaminium cation are involved in hydrogen bonds. The melaminium cations are inter­connected by four N—H⋯N hydrogen bonds, forming ribbons along [111]. The water mol­ecules connected by N—H⋯O hydrogen bonds also form part of these ribbons. The ribbons are inter­connected by other hydrogen bonds (O—H⋯I and N—H⋯I), as well as by ππ inter­actions [centroid–centroid distance = 3.6597 (17) Å].

Related literature

For similar singly protonated melaminium salts, see: Janczak et al. (2001[Janczak, J. & Perpétuo, G. J. (2001). Acta Cryst. C57, 1120-1122.]); Athikomrattanakul et al. (2007[Athikomrattanakul, U., Promptmas, C., Katterle, M. & Schilde, U. (2007). Acta Cryst. E63, o2154-o2156.]). For ferroelectric materials, see: Fu et al. (2009[Fu, D. W., Ge, J. Z., Dai, J., Ye, H. Y. & Qu, Z. R. (2009). Inorg. Chem. Commun. 12, 994-997.]); Hang et al. (2009[Hang, T., Fu, D. W., Ye, Q. & Xiong, R. G. (2009). Cryst. Growth Des. 5, 2026-2029.]). For impedance studies, see: Uthrakumar et al. (2008[Uthrakumar, R., Vesta, C., Raj, C. J., Dinakaran, S., Dhas, R. C. & Das, S. J. (2008). Cryst. Res. Technol. 43, 428-432.]).

[Scheme 1]

Experimental

Crystal data
  • C3H7N6+·I·H2O

  • Mr = 272.06

  • Triclinic, [P \overline 1]

  • a = 6.0655 (12) Å

  • b = 7.0370 (14) Å

  • c = 11.413 (2) Å

  • α = 104.02 (3)°

  • β = 93.95 (3)°

  • γ = 109.08 (3)°

  • V = 440.80 (19) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 3.59 mm−1

  • T = 293 K

  • 0.40 × 0.30 × 0.20 mm

Data collection
  • Rigaku SCXmini diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Version 1.4.0. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.285, Tmax = 0.487

  • 4551 measured reflections

  • 2006 independent reflections

  • 1896 reflections with I > 2σ(I)

  • Rint = 0.029

Refinement
  • R[F2 > 2σ(F2)] = 0.026

  • wR(F2) = 0.067

  • S = 1.11

  • 2006 reflections

  • 106 parameters

  • 3 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.47 e Å−3

  • Δρmin = −0.61 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2A⋯O1 0.86 1.87 2.724 (4) 172
N4—H4A⋯I1i 0.86 2.95 3.764 (3) 159
N4—H4B⋯I1ii 0.86 3.20 3.758 (3) 125
N6—H6A⋯I1iii 0.86 2.88 3.647 (3) 149
N6—H6B⋯N1iv 0.86 2.15 3.009 (3) 173
O1—H1A⋯I1v 0.83 (2) 3.13 (4) 3.760 (4) 134 (5)
O1—H1A⋯I1vi 0.83 (2) 3.39 (5) 3.778 (3) 112 (4)
O1—H1B⋯I1 0.82 (2) 3.00 (3) 3.732 (4) 150 (5)
N5—H5A⋯N3vii 0.86 2.15 3.013 (4) 177
N5—H5B⋯I1v 0.86 2.97 3.698 (3) 143
Symmetry codes: (i) x-1, y, z; (ii) -x+1, -y+1, -z; (iii) -x+1, -y+1, -z+1; (iv) -x, -y+1, -z+1; (v) x, y-1, z; (vi) -x+2, -y+1, -z; (vii) -x+1, -y, -z+1.

Data collection: CrystalClear (Rigaku, 2005[Rigaku (2005). CrystalClear. Version 1.4.0. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: PRPKAPPA (Ferguson, 1999[Ferguson, G. (1999). PRPKAPPA. University of Guelph, Canada.]).

Supporting information


Comment top

The melamine molecule and its organic and inorganic complexes or salts can develop supramolecular structures via multiple hydrogen-bonding systems by self-assembly of components which contain abundant hydrogen-bonding sites (Janczak et al., 2001; Athikomrattanakul et al., 2007). The present study is a part of systematic investigation of ferroelectric materials (Fu et al., 2009; Hang et al., 2009) that include metal-organic coordination compounds with organic ligands or are related to the structures with both organic and inorganic building fragments.

The compound was characterized by the X-ray powder diffraction (XRPD) at room temperature. The pattern calculated from the single-crystal X-ray data was in a good agreement with the observed at to the peak positions but with different peak intensities.

The structure is composed of the melaminium cations, iodide anions and the water molecules (Fig. 1). The melaminium cation is protonated at only one melamine site. The six-membered melaminium ring exhibits distortions from the regular hexagonal form. The internal C—N—C angle at the protonated N atom (119.5 (2)°) is greater than the other two C—N—C angles of the ring (115.5 (2)°) and the internal N—C—N angles involving the unprotonated ring N atoms (126.1 (2)°) are obviously larger than those containing protonated and unprotonated N atoms (121.4 (2)°) .

Fig. 2 shows a view down the b axis. The melaminium cations are interconnected by four N-H···N hydrogen bonds, forming ribbons parallel to (1 1 1). The water molecules connected by N-H···O hydrogen bonds (Tab. 1) form also a part of these ribbons. The ribbons are interconnected by other hydrogen bonds that involve I- as well as by π-electron ring - π-electron ring interactions with the distance between the centroids of the neighbour melaminium rings (1-x,1-y,1-z) equal to 3.6597 (17) Å. The hydrogen bonds are summarized in Tab. 1. It is of interest that water oxygens despite of being quite close to each other are not interconnected by the hydrogen bond. The distance between the water oxygens is 2.9643 (40) Å [Symmetry code: 1-x, 1-y, -z]. The H atom of the protonated ring N atom (H2a) is donated to the water molecule, being involved in a strong N-H···O hydrogen bond. The other amine H atoms are involved in N—H···I and N—H···N hydrogen bonds. I- anions that take part in the electrostatic equilibrium with the melaminium cations are also involved in O—H···I hydrogen bonds.

Related literature top

For similar singly protonated melaminium salts, see: Janczak et al. (2001); Athikomrattanakul et al. (2007). For ferroelectric materials, see: Fu et al. (2009); Hang et al. (2009). For impedance studies, see: Uthrakumar et al. (2008).

Experimental top

Melamine (0.252 g, 0.002 mol) was dissolved in 25 ml of water at 323 K. 0.569 g of 45% (weight concentration) solution of HI was added to the solution. (This amount corresponded to about 0.002 mol of pure HI.) The temperature was maintained at 323 K for one hour while stirring the mixture. Then the solution was let to cool down to room temperature. After several days, the title salt, C3H7N6+.I-.H2O, crystallized from the solution. The crystals were colourless, prismatic and of the average size about 0.2×0.3×0.4 mm.

Refinement top

All the hydrogens were discernible in the difference electron density maps. The positions of the H atoms of the melamine cations were refined using a riding model with N—H = 0.86 Å and Uiso(H) = 1.2Ueq(N). The coordinates of the water hydrogens have been refined under restrains 0.82 (2)Å; Uiso(H) = 1.2Ueq(O). (The constrained and the restrained values fit well to the trial refinement with the freely refined hydrogen parameters.)

Dielectric studies (capacitance and dielectric loss measurements) were performed on powder samples which have been pressed into tablets with conducting carbon glue deposited on their faces. The automatic impedance TongHui2828 Analyzer has been used (Uthrakumar et al., 2008). In the measured temperature range from 80 to 450 K (m.p. > 470 K), the temperature dependence of the relative permittivity at 1 MHz varied smoothly from 3.9 to 5.2 in the title compound. No dielectric anomaly has been observed.

Structure description top

The melamine molecule and its organic and inorganic complexes or salts can develop supramolecular structures via multiple hydrogen-bonding systems by self-assembly of components which contain abundant hydrogen-bonding sites (Janczak et al., 2001; Athikomrattanakul et al., 2007). The present study is a part of systematic investigation of ferroelectric materials (Fu et al., 2009; Hang et al., 2009) that include metal-organic coordination compounds with organic ligands or are related to the structures with both organic and inorganic building fragments.

The compound was characterized by the X-ray powder diffraction (XRPD) at room temperature. The pattern calculated from the single-crystal X-ray data was in a good agreement with the observed at to the peak positions but with different peak intensities.

The structure is composed of the melaminium cations, iodide anions and the water molecules (Fig. 1). The melaminium cation is protonated at only one melamine site. The six-membered melaminium ring exhibits distortions from the regular hexagonal form. The internal C—N—C angle at the protonated N atom (119.5 (2)°) is greater than the other two C—N—C angles of the ring (115.5 (2)°) and the internal N—C—N angles involving the unprotonated ring N atoms (126.1 (2)°) are obviously larger than those containing protonated and unprotonated N atoms (121.4 (2)°) .

Fig. 2 shows a view down the b axis. The melaminium cations are interconnected by four N-H···N hydrogen bonds, forming ribbons parallel to (1 1 1). The water molecules connected by N-H···O hydrogen bonds (Tab. 1) form also a part of these ribbons. The ribbons are interconnected by other hydrogen bonds that involve I- as well as by π-electron ring - π-electron ring interactions with the distance between the centroids of the neighbour melaminium rings (1-x,1-y,1-z) equal to 3.6597 (17) Å. The hydrogen bonds are summarized in Tab. 1. It is of interest that water oxygens despite of being quite close to each other are not interconnected by the hydrogen bond. The distance between the water oxygens is 2.9643 (40) Å [Symmetry code: 1-x, 1-y, -z]. The H atom of the protonated ring N atom (H2a) is donated to the water molecule, being involved in a strong N-H···O hydrogen bond. The other amine H atoms are involved in N—H···I and N—H···N hydrogen bonds. I- anions that take part in the electrostatic equilibrium with the melaminium cations are also involved in O—H···I hydrogen bonds.

For similar singly protonated melaminium salts, see: Janczak et al. (2001); Athikomrattanakul et al. (2007). For ferroelectric materials, see: Fu et al. (2009); Hang et al. (2009). For impedance studies, see: Uthrakumar et al. (2008).

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: PRPKAPPA (Ferguson, 1999).

Figures top
[Figure 1] Fig. 1. The title molecules with the atomic numbering scheme. The displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. A view of the structure along the b axis. The dashed lines depict the hydrogen bonds.
2,4,6-triamino-1,3,5-triazin-1-ium iodide monohydrate top
Crystal data top
C3H7N6+·I·H2OZ = 2
Mr = 272.06F(000) = 260
Triclinic, P1Dx = 2.050 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.0655 (12) ÅCell parameters from 4510 reflections
b = 7.0370 (14) Åθ = 3.2–27.5°
c = 11.413 (2) ŵ = 3.59 mm1
α = 104.02 (3)°T = 293 K
β = 93.95 (3)°Prism, colourless
γ = 109.08 (3)°0.40 × 0.30 × 0.20 mm
V = 440.80 (19) Å3
Data collection top
Rigaku SCXmini
diffractometer
2006 independent reflections
Radiation source: fine-focus sealed tube1896 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 3.2°
ω scansh = 77
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 99
Tmin = 0.285, Tmax = 0.487l = 1414
4551 measured reflections
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)] = 0.026Hydrogen site location: difference Fourier map
wR(F2) = 0.067H atoms treated by a mixture of independent and constrained refinement
S = 1.11 w = 1/[σ2(Fo2) + (0.0285P)2 + 0.1083P]
where P = (Fo2 + 2Fc2)/3
2006 reflections(Δ/σ)max = 0.008
106 parametersΔρmax = 0.47 e Å3
3 restraintsΔρmin = 0.61 e Å3
30 constraints
Crystal data top
C3H7N6+·I·H2Oγ = 109.08 (3)°
Mr = 272.06V = 440.80 (19) Å3
Triclinic, P1Z = 2
a = 6.0655 (12) ÅMo Kα radiation
b = 7.0370 (14) ŵ = 3.59 mm1
c = 11.413 (2) ÅT = 293 K
α = 104.02 (3)°0.40 × 0.30 × 0.20 mm
β = 93.95 (3)°
Data collection top
Rigaku SCXmini
diffractometer
2006 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
1896 reflections with I > 2σ(I)
Tmin = 0.285, Tmax = 0.487Rint = 0.029
4551 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0263 restraints
wR(F2) = 0.067H atoms treated by a mixture of independent and constrained refinement
S = 1.11Δρmax = 0.47 e Å3
2006 reflectionsΔρmin = 0.61 e Å3
106 parameters
Special details top

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 > 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
N10.1770 (4)0.3970 (4)0.3846 (2)0.0392 (5)
N20.4296 (4)0.2565 (4)0.2773 (2)0.0433 (5)
H2A0.50390.24630.21590.052*
N30.3428 (4)0.1720 (4)0.4600 (2)0.0402 (5)
N40.2758 (6)0.4725 (5)0.2059 (3)0.0567 (7)
H4A0.19120.55040.21210.068*
H4B0.35040.45760.14490.068*
N60.1007 (5)0.3160 (4)0.5631 (2)0.0510 (6)
H6A0.11610.25330.61750.061*
H6B0.01440.39250.57130.061*
O10.6721 (6)0.1912 (5)0.0884 (3)0.0817 (9)
H1A0.707 (10)0.091 (5)0.051 (5)0.123*
H1B0.731 (10)0.301 (5)0.070 (5)0.123*
C10.2911 (5)0.3752 (4)0.2904 (3)0.0401 (6)
C20.2097 (5)0.2947 (4)0.4671 (2)0.0375 (5)
C30.4499 (5)0.1533 (4)0.3622 (3)0.0414 (6)
I10.89281 (4)0.76920 (3)0.134131 (16)0.05182 (10)
N50.5833 (5)0.0365 (5)0.3468 (3)0.0562 (7)
H5A0.60100.02760.40000.067*
H5B0.65250.02460.28350.067*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0500 (13)0.0449 (12)0.0330 (11)0.0251 (10)0.0130 (10)0.0164 (10)
N20.0505 (13)0.0533 (13)0.0369 (12)0.0275 (11)0.0152 (10)0.0170 (11)
N30.0489 (12)0.0450 (12)0.0339 (12)0.0243 (10)0.0076 (10)0.0133 (10)
N40.0751 (18)0.0785 (19)0.0448 (15)0.0473 (16)0.0294 (14)0.0350 (14)
N60.0732 (17)0.0630 (16)0.0401 (13)0.0427 (14)0.0239 (12)0.0264 (12)
O10.093 (2)0.086 (2)0.080 (2)0.0379 (18)0.0513 (17)0.0311 (18)
C10.0445 (14)0.0427 (14)0.0369 (14)0.0182 (12)0.0088 (11)0.0136 (11)
C20.0415 (13)0.0382 (13)0.0330 (13)0.0148 (11)0.0054 (11)0.0095 (11)
C30.0424 (14)0.0453 (14)0.0375 (14)0.0186 (12)0.0035 (11)0.0099 (12)
I10.06273 (16)0.06633 (16)0.03972 (14)0.03312 (12)0.01791 (10)0.02193 (11)
N50.0674 (17)0.0751 (18)0.0485 (16)0.0474 (15)0.0192 (13)0.0240 (14)
Geometric parameters (Å, º) top
N1—C11.322 (3)N4—H4B0.8600
N1—C21.357 (3)N6—C21.321 (4)
N2—C11.357 (3)N6—H6A0.8600
N2—C31.366 (4)N6—H6B0.8600
N2—H2A0.8600O1—H1A0.831 (18)
N3—C31.330 (4)O1—H1B0.822 (18)
N3—C21.354 (3)C3—N51.321 (4)
N4—C11.325 (4)N5—H5A0.8600
N4—H4A0.8600N5—H5B0.8600
C1—N1—C2115.6 (2)N1—C1—N4120.5 (3)
C1—N2—C3119.5 (2)N1—C1—N2121.9 (2)
C1—N2—H2A120.3N4—C1—N2117.6 (3)
C3—N2—H2A120.3N6—C2—N3117.0 (2)
C3—N3—C2115.5 (2)N6—C2—N1117.0 (2)
C1—N4—H4A120.0N3—C2—N1126.1 (2)
C1—N4—H4B120.0N5—C3—N3120.1 (3)
H4A—N4—H4B120.0N5—C3—N2118.5 (3)
C2—N6—H6A120.0N3—C3—N2121.4 (2)
C2—N6—H6B120.0C3—N5—H5A120.0
H6A—N6—H6B120.0C3—N5—H5B120.0
H1A—O1—H1B115 (3)H5A—N5—H5B120.0
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O10.861.872.724 (4)172
N4—H4A···I1i0.862.953.764 (3)159
N4—H4B···I1ii0.863.203.758 (3)125
N6—H6A···I1iii0.862.883.647 (3)149
N6—H6B···N1iv0.862.153.009 (3)173
O1—H1A···I1v0.83 (2)3.13 (4)3.760 (4)134 (5)
O1—H1A···I1vi0.83 (2)3.39 (5)3.778 (3)112 (4)
O1—H1B···I10.82 (2)3.00 (3)3.732 (4)150 (5)
N5—H5A···N3vii0.862.153.013 (4)177
N5—H5B···I1v0.862.973.698 (3)143
Symmetry codes: (i) x1, y, z; (ii) x+1, y+1, z; (iii) x+1, y+1, z+1; (iv) x, y+1, z+1; (v) x, y1, z; (vi) x+2, y+1, z; (vii) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaC3H7N6+·I·H2O
Mr272.06
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.0655 (12), 7.0370 (14), 11.413 (2)
α, β, γ (°)104.02 (3), 93.95 (3), 109.08 (3)
V3)440.80 (19)
Z2
Radiation typeMo Kα
µ (mm1)3.59
Crystal size (mm)0.40 × 0.30 × 0.20
Data collection
DiffractometerRigaku SCXmini
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2005)
Tmin, Tmax0.285, 0.487
No. of measured, independent and
observed [I > 2σ(I)] reflections
4551, 2006, 1896
Rint0.029
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.067, 1.11
No. of reflections2006
No. of parameters106
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.47, 0.61

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), PRPKAPPA (Ferguson, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O10.861.872.724 (4)171.7
N4—H4A···I1i0.862.953.764 (3)158.7
N4—H4B···I1ii0.863.203.758 (3)125.1
N6—H6A···I1iii0.862.883.647 (3)149.4
N6—H6B···N1iv0.862.153.009 (3)172.6
O1—H1A···I1v0.831 (18)3.13 (4)3.760 (4)134 (5)
O1—H1A···I1vi0.831 (18)3.39 (5)3.778 (3)112 (4)
O1—H1B···I10.822 (18)3.00 (3)3.732 (4)150 (5)
N5—H5A···N3vii0.862.153.013 (4)176.9
N5—H5B···I1v0.862.973.698 (3)143.4
Symmetry codes: (i) x1, y, z; (ii) x+1, y+1, z; (iii) x+1, y+1, z+1; (iv) x, y+1, z+1; (v) x, y1, z; (vi) x+2, y+1, z; (vii) x+1, y, z+1.
 

Acknowledgements

The authors are grateful to the starter fund of Southeast University for financial support to purchase the diffractometer.

References

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