Bis(melaminium) tartrate dihydrate

Abstract

In the title compound, 2C₃H₇N₆ ⁺·C₄H₄O₆ ²⁻·2H₂O, in which the complete anion is generated by crystallographic twofold symmetry, there are O—H⋯O, N—H⋯O and N—H⋯N hydrogen-bonding inter­actions between neighbouring moieties, forming layers parallel to the bc plane. In addition, π–π contacts [centroid–centroid distance = 3.6541 (9) Å] between the six-membered rings of the melamine cations are observed.

Related literature

For general background, see: Row (1999 ▶); Krische & Lehn (2000 ▶); Sherrington & Taskinen (2001 ▶); Marchewka et al. (2003 ▶); Thushari et al. (2005 ▶). For related structures, see: Udaya Lakshmi et al. (2006 ▶).

Experimental

Crystal data

• 2C₃H₇N₆ ⁺·C₄H₄O₆ ²⁻·2H₂O

• M _r = 436.38

• Monoclinic,

• a = 7.6963 (9) Å

• b = 21.955 (3) Å

• c = 10.7405 (12) Å

• β = 98.179 (6)°

• V = 1796.4 (4) ų

• Z = 4

• Mo Kα radiation

• μ = 0.14 mm⁻¹

• T = 296 K

• 0.26 × 0.22 × 0.12 mm

Data collection

• Bruker APEXII area-detector diffractometer

• Absorption correction: multiscan (SADABS; Sheldrick, 1996 ▶) T _min = 0.963, T _max = 0.980

• 13436 measured reflections

• 2047 independent reflections

• 1712 reflections with I > 2σ(I)

• R _int = 0.027

Refinement

• R[F ² > 2σ(F ²)] = 0.037

• wR(F ²) = 0.108

• S = 1.00

• 2047 reflections

• 166 parameters

• 15 restraints

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

• Δρ_max = 0.25 e Å⁻³

• Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; 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: SHELXTL.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O2i	0.870 (11)	1.802 (12)	2.6680 (14)	173.2 (16)
N1—H1NA⋯O1	0.884 (13)	2.271 (14)	3.0466 (19)	146.3 (16)
N1—H1NB⋯N4ii	0.879 (13)	2.151 (13)	3.0287 (19)	177.3 (17)
N2—H2NA⋯O3	0.889 (15)	2.093 (15)	2.8333 (16)	140.2 (14)
N2—H2NA⋯O1	0.889 (15)	2.190 (15)	2.9497 (18)	143.2 (14)
N3—H3NA⋯O1Wiii	0.872 (14)	2.261 (19)	2.8609 (18)	125.9 (15)
N3—H3NA⋯O3	0.872 (14)	2.573 (16)	3.2241 (18)	132.2 (16)
N3—H3NB⋯N6iv	0.900 (14)	2.133 (14)	3.0313 (19)	176.2 (18)
N5—H5NA⋯O1Wv	0.901 (13)	1.940 (14)	2.8148 (16)	163.2 (15)
N5—H5NB⋯O2vi	0.895 (13)	2.153 (15)	2.9581 (16)	149.4 (15)
O1W—H1WA⋯O1	0.858 (14)	1.852 (14)	2.6861 (16)	163.8 (17)
O1W—H1WB⋯O2vii	0.804 (13)	2.297 (15)	2.9738 (17)	142.3 (17)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

supplementary crystallographic information

Comment

Melamine and its organic and inorganic counterparts can develop supramolecular assemblies via multiple hydrogen bonds (Row, 1999; Krische & Lehn, 2000; Sherrington & Taskinen, 2001; Marchewka et al., 2003), while tartaric acid is a small organic molecule [C₄H₄O₆] with a bewildering array of ligation possibilities (Thushari et al., 2005). Herein we report the synthesis and crystal structure of the title compound (I).

In (I) (Fig. 1), the melaminium cations form infinite floors via N—H···N hydrogen bonds and the D-tartrate anions link pair with waters via O—H···O form floors lying between two floors of melaminium. Furthermore, the N—H···O hydrogen bonds connected the neighboring cations floors and anions floors is together into a three-dimensional network. We found that the architecture of compound (I) is similar to bis (melaminium) L– tartrate 2.5-hydrate (Udaya Lakshmi et al., 2006) but not the same, which indicate that using different stereo-chemical configurations can give different three-dimensional arrangements. In addition, π–π contacts [centroid-centroid distance 3.6541 (9) Å] between the six-membered rings of the melamine moieties are observed.

Experimental

Compound (I) is formed by hydrothermal reaction of D-tartaric acid (1.5 mmol) and Melamine (1 mmol) in 15 ml water for 2 days at 533 K.

Refinement

The H atoms bonded to C atoms were positioned geometrically [C—H 0.96 Å U_iso(H) = 1.2U_eq(C)]. The H atoms bonded to O atoms were located in a difference Fourier maps and their positions were refined isotropically, with O—H distances fixed by O—H = 0.85 (2) Å and H ··· H = 1.30 (2) Å, their displacement parameters were set to 1.5U_eq(O). The H atoms bonded to N atoms were located in a difference Fourier maps and their positions were refined isotropically, with N—H distances fixed by N—H = 0.90 (2) Å and H ··· H = 1.56 (2) Å, their displacement parameters were set to 1.2U_eq(N).

Figures

Fig. 1.

View of the molecule of (I), showing the atom-numbering scheme. Displacement ellipsoids plotted at 30% probability level. [The atoms labelled with 'A' are related to the center of inversion].

Fig. 2.

Packing diagram for compound (I). The O—H···O and O—H···N interactions are depicted by dashed lines.

Crystal data

2C3H7N6+·C4H4O62−·2H2O	F(000) = 920
Mr = 436.38	Dx = 1.621 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4811 reflections
a = 7.6963 (9) Å	θ = 1.9–27.5°
b = 21.955 (3) Å	µ = 0.14 mm−1
c = 10.7405 (12) Å	T = 296 K
β = 98.179 (6)°	Block, colourless
V = 1796.4 (4) Å3	0.26 × 0.22 × 0.12 mm
Z = 4

Data collection

Bruker APEXII area-detector diffractometer	2047 independent reflections
Radiation source: fine-focus sealed tube	1712 reflections with I > 2σ(I)
graphite	Rint = 0.027
ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→10
Tmin = 0.963, Tmax = 0.980	k = −27→28
13436 measured reflections	l = −13→13

Refinement

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ2(Fo2) + (0.059P)2 + 0.9299P] where P = (Fo2 + 2Fc2)/3
2047 reflections	(Δ/σ)max < 0.001
166 parameters	Δρmax = 0.25 e Å−3
15 restraints	Δρmin = −0.24 e Å−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.25143 (17)	0.05132 (5)	0.11300 (12)	0.0603 (3)
O2	0.17077 (17)	−0.04576 (5)	0.08785 (10)	0.0535 (3)
O3	0.15841 (13)	0.05730 (4)	0.33946 (9)	0.0394 (3)
H3	0.158 (2)	0.0508 (7)	0.4193 (11)	0.047*
N1	0.06055 (18)	0.17081 (6)	0.04393 (13)	0.0470 (3)
H1NA	0.074 (2)	0.1308 (6)	0.0459 (17)	0.056*
H1NB	−0.004 (2)	0.1902 (7)	−0.0177 (15)	0.056*
N2	0.23582 (16)	0.17105 (6)	0.23551 (12)	0.0428 (3)
H2NA	0.233 (2)	0.1306 (7)	0.2342 (16)	0.051*
N3	0.4140 (2)	0.17049 (7)	0.42646 (15)	0.0558 (4)
H3NA	0.407 (2)	0.1308 (7)	0.4247 (18)	0.067*
H3NB	0.477 (2)	0.1917 (8)	0.4890 (16)	0.067*
N4	0.32789 (15)	0.26210 (5)	0.33724 (11)	0.0373 (3)
N5	0.22621 (18)	0.35022 (5)	0.24256 (11)	0.0451 (3)
H5NA	0.157 (2)	0.3702 (8)	0.1812 (13)	0.054*
H5NB	0.282 (2)	0.3704 (8)	0.3088 (13)	0.054*
N6	0.13898 (15)	0.26268 (5)	0.13787 (10)	0.0353 (3)
C1	0.18246 (18)	0.00368 (6)	0.14673 (13)	0.0392 (3)
C2	0.09995 (16)	0.00520 (5)	0.26757 (11)	0.0308 (3)
H2A	0.1329	−0.0309	0.3157	0.037*
C3	0.23110 (16)	0.29059 (6)	0.23929 (11)	0.0338 (3)
C4	0.14503 (16)	0.20248 (6)	0.13831 (13)	0.0352 (3)
C5	0.32593 (17)	0.20212 (6)	0.33379 (13)	0.0386 (3)
O1W	0.45183 (14)	0.06665 (5)	−0.06993 (11)	0.0465 (3)
H1WA	0.391 (2)	0.0544 (8)	−0.0137 (16)	0.056*
H1WB	0.535 (2)	0.0446 (8)	−0.0730 (17)	0.056*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0750 (8)	0.0567 (7)	0.0575 (7)	0.0020 (6)	0.0378 (6)	0.0128 (6)
O2	0.0879 (8)	0.0446 (6)	0.0312 (5)	0.0254 (5)	0.0197 (5)	0.0046 (4)
O3	0.0533 (6)	0.0362 (5)	0.0272 (5)	−0.0122 (4)	0.0010 (4)	0.0008 (4)
N1	0.0582 (8)	0.0324 (6)	0.0480 (8)	−0.0069 (5)	−0.0006 (6)	−0.0048 (5)
N2	0.0496 (7)	0.0278 (6)	0.0494 (7)	0.0002 (5)	0.0013 (5)	0.0020 (5)
N3	0.0641 (8)	0.0382 (7)	0.0591 (9)	0.0069 (6)	−0.0120 (7)	0.0110 (6)
N4	0.0433 (6)	0.0337 (6)	0.0333 (6)	0.0020 (4)	0.0003 (5)	0.0027 (4)
N5	0.0658 (8)	0.0288 (6)	0.0358 (7)	−0.0001 (5)	−0.0097 (6)	0.0001 (5)
N6	0.0434 (6)	0.0308 (6)	0.0310 (6)	−0.0022 (4)	0.0033 (5)	0.0001 (4)
C1	0.0454 (7)	0.0420 (8)	0.0320 (7)	0.0151 (6)	0.0118 (5)	0.0100 (5)
C2	0.0422 (7)	0.0264 (6)	0.0236 (6)	0.0017 (5)	0.0046 (5)	0.0031 (4)
C3	0.0395 (6)	0.0329 (7)	0.0291 (6)	−0.0004 (5)	0.0048 (5)	0.0012 (5)
C4	0.0366 (6)	0.0328 (7)	0.0372 (7)	−0.0028 (5)	0.0086 (5)	−0.0003 (5)
C5	0.0383 (6)	0.0359 (7)	0.0412 (7)	0.0022 (5)	0.0044 (5)	0.0051 (6)
O1W	0.0443 (6)	0.0467 (6)	0.0496 (6)	0.0051 (4)	0.0102 (5)	0.0143 (5)

Geometric parameters (Å, °)

O1—C1	1.2497 (18)	N4—C5	1.3174 (18)
O2—C1	1.2530 (18)	N4—C3	1.3527 (16)
O3—C2	1.4170 (15)	N5—C3	1.3104 (18)
O3—H3	0.870 (11)	N5—H5NA	0.901 (13)
N1—C4	1.3215 (18)	N5—H5NB	0.895 (13)
N1—H1NA	0.884 (13)	N6—C4	1.3224 (18)
N1—H1NB	0.879 (13)	N6—C3	1.3583 (16)
N2—C4	1.3590 (18)	C1—C2	1.5242 (18)
N2—C5	1.3610 (18)	C2—C2i	1.531 (2)
N2—H2NA	0.889 (15)	C2—H2A	0.9600
N3—C5	1.3193 (18)	O1W—H1WA	0.858 (14)
N3—H3NA	0.872 (14)	O1W—H1WB	0.804 (13)
N3—H3NB	0.900 (14)
C2—O3—H3	111.1 (11)	O2—C1—C2	116.11 (12)
C4—N1—H1NA	117.6 (12)	O3—C2—C1	110.08 (10)
C4—N1—H1NB	119.1 (12)	O3—C2—C2i	111.37 (8)
H1NA—N1—H1NB	123.3 (16)	C1—C2—C2i	108.42 (12)
C4—N2—C5	119.39 (13)	O3—C2—H2A	109.5
C4—N2—H2NA	119.1 (11)	C1—C2—H2A	109.3
C5—N2—H2NA	121.5 (11)	C2i—C2—H2A	108.2
C5—N3—H3NA	119.1 (13)	N5—C3—N4	117.12 (12)
C5—N3—H3NB	117.1 (12)	N5—C3—N6	117.29 (12)
H3NA—N3—H3NB	123.8 (17)	N4—C3—N6	125.59 (13)
C5—N4—C3	115.95 (12)	N1—C4—N6	120.66 (13)
C3—N5—H5NA	118.9 (11)	N1—C4—N2	117.72 (13)
C3—N5—H5NB	120.3 (11)	N6—C4—N2	121.62 (12)
H5NA—N5—H5NB	120.5 (15)	N4—C5—N3	120.17 (13)
C4—N6—C3	115.71 (11)	N4—C5—N2	121.69 (12)
O1—C1—O2	125.57 (13)	N3—C5—N2	118.14 (14)
O1—C1—C2	118.30 (13)	H1WA—O1W—H1WB	110.6 (16)
O1—C1—C2—O3	−15.91 (17)	C3—N6—C4—N1	−179.76 (12)
O2—C1—C2—O3	165.79 (11)	C3—N6—C4—N2	0.99 (18)
O1—C1—C2—C2i	106.14 (12)	C5—N2—C4—N1	179.33 (13)
O2—C1—C2—C2i	−72.17 (12)	C5—N2—C4—N6	−1.4 (2)
C5—N4—C3—N5	177.80 (13)	C3—N4—C5—N3	−178.79 (13)
C5—N4—C3—N6	−2.34 (19)	C3—N4—C5—N2	1.85 (19)
C4—N6—C3—N5	−179.21 (12)	C4—N2—C5—N4	−0.1 (2)
C4—N6—C3—N4	0.93 (18)	C4—N2—C5—N3	−179.50 (13)

Symmetry codes: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2ii	0.87 (1)	1.80 (1)	2.6680 (14)	173 (2)
N1—H1NA···O1	0.88 (1)	2.27 (1)	3.0466 (19)	146 (2)
N1—H1NB···N4iii	0.88 (1)	2.15 (1)	3.0287 (19)	177 (2)
N2—H2NA···O3	0.89 (2)	2.09 (2)	2.8333 (16)	140 (1)
N2—H2NA···O1	0.89 (2)	2.19 (2)	2.9497 (18)	143 (1)
N3—H3NA···O1Wiv	0.87 (1)	2.26 (2)	2.8609 (18)	126 (2)
N3—H3NA···O3	0.87 (1)	2.57 (2)	3.2241 (18)	132 (2)
N3—H3NB···N6v	0.90 (1)	2.13 (1)	3.0313 (19)	176 (2)
N5—H5NA···O1Wvi	0.90 (1)	1.94 (1)	2.8148 (16)	163 (2)
N5—H5NB···O2vii	0.90 (1)	2.15 (2)	2.9581 (16)	149 (2)
O1W—H1WA···O1	0.86 (1)	1.85 (1)	2.6861 (16)	164 (2)
O1W—H1WB···O2viii	0.80 (1)	2.30 (2)	2.9738 (17)	142 (2)

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