Hydrogen-bonded supra­molecular motifs in the 1:1 monohydrated mol­ecular adduct of acetoguanaminium chloride with acetoguanamine and in 2,4,6-triamino­pyrimidine­diium dichloride dihydrate

In the 1:1 monohydrated mol­ecular adduct 2,4-diamino-6-methyl-1,3,5-triazin-1-ium chloride 2,4-diamino-6-methyl-1,3,5-triazine monohydrate, C₄H₈N₅⁺·Cl^-·C₄H₇N₅·H₂O, formed between 2,4-diamino-6-methyl-1,3,5-triazin-1-ium chloride (acetoguanaminium chloride) and 2,4-diamino-6-methyl-1,3,5-triazine (acetoguanamine), and in triamino­pyrimidine­diium dichloride dihydrate, C₄H₉N₅²⁺·2Cl^-·2H₂O, whose cationic component lies across a twofold rotation axis, the protonation occurs at the ring N atoms and the bond distances in the protonated mol­ecules indicate significant bond alterations, consistent with charge-separated polar forms. The supra­molecular structures of both compounds are stabilized by systems of hydrogen bonds forming complex sheets, inter­linked by sets of hydrogen bonds involving the solvent water mol­ecules and the chloride anions.

S1. Comment

We report here the structures of the 1:1 monohydrated molecular adduct C₄H₈N₅⁺·Cl⁻·C₄H₇N₅. H₂O, (I), formed between 2,4-diamino-6-methyl-1,3,5-triazin-1-ium chloride (acetoguanaminium chloride, AceguH⁺) and 2,4-diamino-6-methyl-1,3,5-triazine (acetoguanamine, Acegu), which we compare with the structure of 2,4,6-triaminopyrimidinediium dichloride dihydrate, C₄H₉N₅²⁺·2Cl⁻·2H₂O, (II) (TripidH₂²⁺). The heterocyclic system in (I) differs from that in (II) only in the replacement of one amino substituent on the triazine ring by a methyl substituent and by the substitution of an N atom for a C atom in the triazine ring, and this provides an opportunity to observe the effects that simple changes of substituent and in the heterocyclic skeleton exert upon the site of protonation and the supramolecular aggregation. This work is a continuation of our studies on 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, 2002; Brunetti et al., 2000, 2002; Portalone & Colapietro, 2004a,b, 2006, 2007a,b,c,d; Portalone, 2007). In this context, our attention has been focused on the protonated form of the two previously mentioned aromatic N-heterocycles, as polyaminopyrimidine and polyamino-1,3,5-triazine are capable of interacting with RNA through Watson–Crick pairing (Gilbert et al., 2006), and the relevance of proton transfer in DNA/RNA systems was demonstrated many years ago (Steenken, 1989, 1997).

The asymmetric unit of compound (I) consists of one protonated (AceguH⁺) and one neutral (Acegu) acetoguanamine molecules, a chloride anion, and a water molecule of crystallization (Fig. 1). Of the different sites available in the acetoguanamine molecule, protonation occurs at one of the two ring N atoms ortho to the C atom bearing the methyl group. Comparison of the molecular geometry of the planar heterocyclic ring of Acegu with that reported for guanamine (Portalone, 2007) shows that the corresponding bond lengths and angles are equal within experimental error and conform to C_s symmetry (Table 3). The effects of protonation can be appreciated by comparing the molecular geometry of the AceguH⁺ cation with that of the free base (Table 3), and can be summarized as follows: (i) an increase of the N11—C12 and N11—C16 bond distances by 0.007 (2) Å and 0.018 (2) Å, respectively; (ii) a decrease of the N13—C12, N15—C16, N16—C12 and N17—C14 bond distances by 0.014 (2)–0.026 (2) Å; (iii) an increase of the C12—N11—C16 bond angle by 5.6 (1)°; (iv) a decrease of the N11—C12—N13 and N11—C16—N15 bond angles by 4.1 (1) and 4.0 (1)°, respectively.

Protonation of atom N11 causes a redistribution of π-electron density so that the resulting distortions in the molecular geometry of the cation, which have been observed in the only two previously reported crystal structures containing the 2,4-diamino-6-methyl-1,3,5-triazin-1-ium unit (Wijaya et al., 2004; Perpétuo & Janczak, 2007), point to the importance of the charge-separated quininoid forms (Ia) and (Ib) (see scheme) as significant contributors.

As previously mentioned, compound (I) crystallizes as a 1:1 monohydrated molecular adduct. In the crystal structure, the hydrogen-bonding scheme is rather complex and involves all available hydrogen-bond donor/acceptor sites except atom O1, which participates as a hydrogen-bond acceptor in only one intermolecular interaction [please clarify; implies that O1 only participates in 1 bond as acceptor, while next sentence states it is actually involved in 3 as donor/acceptor]. In total, the supramolecular structure of (I) is characterized by 11 two-center hydrogen bonds, namely nine N—H···X (X = N, O and Cl⁻) and two O—H···Y bonds (Y = N and Cl⁻) (Table 1), and is dominated by two main motifs. Firstly, an R²₂(8) ring (Etter et al., 1990; Bernstein et al., 1995; Motherwell et al., 1999) forms from N—H···N double intermolecular hydrogen bonds between centrosymmetric coplanar Acegu pairs. These pairs further self-organize through R²₂(8) N—H···N double intermolecular hydrogen bonds with centrosymmetric coplanar R²₂(8) AceguH⁺ pairs to generate infinite chains of rings running approximately parallel to the [010] direction (Fig. 2). In other words, this hydrogen-bonding scheme corresponds to an alternating double repetition of AceguH⁺ and Acegu molecules. These infinite chains are then crosslinked by one N⁺—H···O, one O—H···N and four N—H···Cl⁻ intermolecular hydrogen bonds between pairs of Acegu and AceguH⁺ molecules, forming a sheet-like structure via four adjoining hydrogen-bonded rings [R²₃(8), R²₃(8), R²₄(8) and R³₄(12)], and form the second major motif, also shown in Fig. 2. The hydrogen bonds so far discussed in the two-dimensional arrays in the bc plane are bridged by water molecules via O—H ···Cl⁻ interactions. It is noteworthy that in AceguH⁺, where the charge-separated forms (Ia) and (Ib) are significant, the intermolecular N—H···Cl⁻ and N—H···N hydrogen bonds are characterized by shorter N···Cl⁻ and N···N distances (Table 1) than those in Acegu, where the development of comparable charge-separated forms is not possible.

The asymmetric unit of compound (II) comprises a planar half-molecule of 2,4,6-triaminopyrimidine disposed about a twofold axis along the line joining atoms N6, C2 and C5 and protonated at the ring N atom (TripidH⁺), a chloride anion and a water molecule of crystallization (Fig. 3). Comparison of the molecular geometry of TripidH⁺ with that reported for the free base (Schwalbe & Williams, 1982) was not possible because of the low accuracy of this structure determination (twinned crystals, R = 0.104 with a data-to-parameter ratio of 4.9 and standard deviations of 0.01 Å in bond lengths and 0.8° in bond angles for the two molecules in the asymmetric unit). Consequently, the effects of protonation can be appreciated by matching the molecular geometry of the TripidH⁺ cation with that of Acegu (Table 3). As for (I), the observed geometrical distortions suggest that the charge-separated quininoid forms (IIa), (IIb) and (IIc) (see scheme) are significant contributors to the overall molecular–electronic structure.

The crystal packing of (II) involves all available hydrogen donor/acceptor sites, and is stabilized by seven hydrogen bonds, namely five N—H···X (X = O and Cl⁻) and two O—H···Cl⁻ (Table 2). The supramolecular structure takes the form of sheets generated by a combination of N—H···Cl⁻, N—H···O and O—H···Cl⁻ hydrogen bonds (Fig. 4); this may be contrasted with (I), where N—H···N and O—H···N hydrogen bonds were present. Moreover, at variance with the previously observed supramolecular organization of (I), in the two-dimensional arrays water molecules and Cl⁻ anions act as bridges between TripidH₂²⁺ cations, forming three different types of hydrogen-bonded rings, one of R²₂(8) type, one of R¹₂(6) type and one of R³₄(8) type. The (010)-nets thus formed are themselves linked into a three-dimensional network by pairs of O1—H1···Cl1ⁱⁱⁱ [symmetry code: (iii) −x + 3/2, −y − 1/2, −z + 1/2] hydrogen bonds, so forming centrosymmetric hydrogen-bonded rings of R²₄(8) motif and approximately in the [001] direction (Fig. 4). In one of the three N—H···Cl⁻ interactions, where atom N7 acts as a hydrogen-bond donor via atom H71, there is some uncertainty as to whether this is a hydrogen bond or not. However, as is very frequently found for bifurcated hydrogen bonds, the sum of the inter-bond angles at the H atom is close to 360° and the H···Cl⁻ distance can be greater than the van der Waals separation (Jeffrey & Saenger, 1991; Desiraju & Steiner, 1999; Steiner, 2002).

Related literature

For related literature, see: Bernstein et al. (1995); Brunetti et al. (2000); Desiraju & Steiner (1999); Etter et al. (1990); Gilbert et al. (2006); Jeffrey & Saenger (1991); Motherwell et al. (1999); Perpétuo & Janczak (2007); Portalone (2007); Portalone & Colapietro (2006); Portalone et al. (1999, 2002); Schwalbe & Williams (1982); Steenken (1989); Steiner (2002); Wijaya et al. (2004).

S2. Experimental

Compounds (I) and (II) (0.5 mmol, Aldrich, 98% purity) were dissolved without further purification in 8 ml of hot dimethylformamide and in 10 ml of methanol/chloroform (3:1), respectively. While stirring, HCl (6 mol l⁻¹) was added dropwise until the pH reached 2. After several days, colourless single crystals suitable for X-ray experiments were obtained by slow evaporation of the solvents.

S3. Refinement

All H atoms of both compounds were found in difference maps. In (I), positional and isotropic parameters of H atoms of the amino groups and of the triazine ring, as well as positional parameters of H atoms of the water molecule for which U_iso(H) values were set equal to 1.5U_eq(O1), were refined. H atoms from the methyl groups were positioned with idealized geometry and refined isotropically using a riding model [C—H = 0.88–0.91 Å and U_iso(H) = 1.5U_eq(C)]. In (II), positional and isotropic displacement parameters of all H atoms were refined.

Computing details

For both compounds, data collection: XCS (Colapietro et al., 1992); cell refinement: XCS (Colapietro et al., 1992); data reduction: XCS (Colapietro et al., 1992); 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 (Sheldrick, 1997).

Figures

	Fig. 1. The crystallographic asymmetric unit in (I), showing the atom-labelling scheme and hydrogen bonding (dashed lines). Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Perspective view of crystal packing for (I) down the approximate c axis direction. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonding is indicated by dashed lines.
	Fig. 3. The molecular components in (II), showing the cation C4H9N5^2+ lying across a twofold axis, the two water molecules of crystallization and the Cl^− counterions. In the picture, showing the atom-labelling scheme and hydrogen bonding (dashed lines), atoms marked with * are at the symmetry positions (3/2 − x, y, 1 − z). Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 4. Perspective view of crystal packing for (II) down the approximate b axis direction. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonding is indicated by dashed lines. Selected atoms are labelled. [symmetry codes: (iii) 3/2 − x, −1/2 − y, 1/2 − z].

(I) 2,4-diamino-6-methyl-1,3,5-triazin-1-ium chloride 2,4-diamino-6-methyl-1,3,5-triazine monohydrate

Crystal data

C4H8N5^+·Cl^−·C4H7N5·H2O	Z = 2
Mr = 304.77	F(000) = 320
Triclinic, P1	Dx = 1.473 Mg m^−3
Hall symbol: -P 1'	Mo Kα radiation, λ = 0.710689 Å
a = 7.3808 (9) Å	Cell parameters from 96 reflections
b = 9.4538 (10) Å	θ = 15–20°
c = 10.3942 (9) Å	µ = 0.29 mm^−1
α = 90.971 (12)°	T = 298 K
β = 101.554 (14)°	Block, colorless
γ = 104.252 (16)°	0.20 × 0.20 × 0.10 mm
V = 687.03 (13) Å^3

Data collection

Huber CS four-circle diffractometer	2246 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.018
Graphite monochromator	θmax = 25.0°, θmin = 2.0°
ω scan	h = 0→8
Absorption correction: ψ scan (North et al., 1968)	k = −10→10
Tmin = 0.940, Tmax = 0.971	l = −12→12
2758 measured reflections	3 standard reflections every 97 reflections
2324 independent reflections	intensity decay: 2%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.092	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0548P)^2 + 0.205P] where P = (Fo^2 + 2Fc^2)/3
2324 reflections	(Δ/σ)max < 0.001
227 parameters	Δρmax = 0.23 e Å^−3
0 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
N1	0.30571 (18)	1.40729 (13)	0.84837 (12)	0.0328 (3)
C2	0.2554 (2)	1.26503 (15)	0.80213 (14)	0.0293 (3)
N3	0.27914 (17)	1.21687 (13)	0.68572 (12)	0.0313 (3)
C4	0.3592 (2)	1.32133 (16)	0.61422 (14)	0.0297 (3)
N5	0.41924 (18)	1.46575 (13)	0.65268 (12)	0.0338 (3)
C6	0.3882 (2)	1.50059 (16)	0.76911 (15)	0.0322 (3)
C8	0.4509 (3)	1.65832 (18)	0.81332 (18)	0.0466 (4)
H8A	0.4709	1.6685	0.9022	0.070*
H8B	0.3592	1.7029	0.7774	0.070*
H8C	0.5608	1.6998	0.7873	0.070*
N6	0.1773 (2)	1.16622 (16)	0.87846 (15)	0.0413 (3)
H61	0.159 (3)	1.194 (2)	0.947 (2)	0.051 (6)*
H62	0.144 (3)	1.076 (3)	0.852 (2)	0.058 (6)*
N7	0.3846 (2)	1.28211 (17)	0.49635 (13)	0.0395 (3)
H71	0.432 (3)	1.353 (2)	0.4562 (19)	0.042 (5)*
H72	0.342 (3)	1.196 (2)	0.468 (2)	0.046 (5)*
N11	0.21773 (18)	0.71853 (14)	0.27590 (13)	0.0328 (3)
H11	0.228 (3)	0.676 (2)	0.208 (2)	0.043 (5)*
C12	0.1397 (2)	0.63373 (15)	0.36561 (14)	0.0307 (3)
N13	0.11409 (18)	0.69417 (13)	0.47482 (12)	0.0327 (3)
C14	0.1703 (2)	0.84119 (16)	0.49031 (14)	0.0321 (3)
N15	0.24954 (19)	0.93143 (13)	0.40286 (13)	0.0354 (3)
C16	0.2686 (2)	0.86615 (16)	0.29708 (15)	0.0326 (3)
C18	0.3468 (3)	0.95142 (18)	0.19338 (17)	0.0433 (4)
H18A	0.3235	0.8943	0.1212	0.065*
H18B	0.4709	0.9866	0.2203	0.065*
H18C	0.2924	1.0240	0.1770	0.065*
N16	0.0889 (2)	0.49105 (15)	0.34208 (16)	0.0398 (3)
H161	0.100 (3)	0.457 (2)	0.276 (2)	0.044 (5)*
H162	0.034 (3)	0.443 (2)	0.395 (2)	0.042 (5)*
N17	0.1487 (2)	0.90502 (16)	0.59694 (14)	0.0433 (4)
H171	0.186 (3)	0.995 (3)	0.611 (2)	0.049 (5)*
H172	0.103 (3)	0.858 (2)	0.649 (2)	0.049 (6)*
Cl1	0.00214 (7)	0.20585 (4)	0.14171 (4)	0.04651 (16)
O1	0.2077 (3)	0.57992 (19)	0.04704 (14)	0.0621 (4)
H1	0.247 (4)	0.526 (3)	0.019 (3)	0.093*
H2	0.135 (4)	0.623 (3)	−0.013 (3)	0.093*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0420 (7)	0.0270 (6)	0.0301 (6)	0.0057 (5)	0.0129 (5)	0.0006 (5)
C2	0.0334 (7)	0.0271 (7)	0.0279 (7)	0.0071 (5)	0.0080 (5)	0.0032 (6)
N3	0.0399 (7)	0.0247 (6)	0.0294 (6)	0.0053 (5)	0.0109 (5)	0.0028 (5)
C4	0.0344 (7)	0.0275 (7)	0.0278 (7)	0.0076 (5)	0.0085 (5)	0.0040 (5)
N5	0.0432 (7)	0.0259 (6)	0.0331 (6)	0.0046 (5)	0.0146 (5)	0.0035 (5)
C6	0.0355 (7)	0.0274 (7)	0.0335 (7)	0.0056 (6)	0.0099 (6)	0.0018 (6)
C8	0.0624 (11)	0.0283 (8)	0.0472 (9)	−0.0001 (7)	0.0223 (8)	−0.0036 (7)
N6	0.0627 (9)	0.0288 (7)	0.0341 (7)	0.0039 (6)	0.0241 (6)	0.0031 (6)
N7	0.0602 (9)	0.0282 (7)	0.0316 (7)	0.0047 (6)	0.0213 (6)	0.0025 (6)
N11	0.0439 (7)	0.0265 (6)	0.0285 (7)	0.0079 (5)	0.0104 (5)	0.0002 (5)
C12	0.0335 (7)	0.0255 (7)	0.0325 (7)	0.0072 (6)	0.0060 (6)	0.0027 (6)
N13	0.0419 (7)	0.0234 (6)	0.0332 (6)	0.0066 (5)	0.0111 (5)	0.0025 (5)
C14	0.0394 (8)	0.0253 (7)	0.0311 (7)	0.0069 (6)	0.0077 (6)	0.0027 (6)
N15	0.0475 (7)	0.0238 (6)	0.0339 (7)	0.0053 (5)	0.0112 (5)	0.0021 (5)
C16	0.0370 (7)	0.0268 (7)	0.0328 (7)	0.0065 (6)	0.0063 (6)	0.0038 (6)
C18	0.0566 (10)	0.0340 (8)	0.0405 (9)	0.0071 (7)	0.0185 (7)	0.0073 (7)
N16	0.0583 (9)	0.0241 (7)	0.0379 (8)	0.0064 (6)	0.0176 (7)	−0.0009 (6)
N17	0.0721 (10)	0.0224 (7)	0.0362 (8)	0.0039 (6)	0.0238 (7)	0.0011 (6)
Cl1	0.0694 (3)	0.0358 (2)	0.0400 (2)	0.01252 (19)	0.0258 (2)	0.00338 (17)
O1	0.0835 (10)	0.0724 (10)	0.0405 (7)	0.0330 (8)	0.0207 (7)	−0.0053 (7)

Geometric parameters (Å, º)

N1—C6	1.3372 (19)	N11—H11	0.83 (2)
N1—C2	1.3559 (19)	C12—N16	1.313 (2)
C2—N6	1.333 (2)	C12—N13	1.3297 (19)
C2—N3	1.3444 (19)	N13—C14	1.3459 (19)
N3—C4	1.3381 (19)	C14—N17	1.309 (2)
C4—N7	1.336 (2)	C14—N15	1.375 (2)
C4—N5	1.3538 (19)	N15—C16	1.301 (2)
N5—C6	1.327 (2)	C16—C18	1.481 (2)
C6—C8	1.483 (2)	C18—H18A	0.8790
C8—H8A	0.9055	C18—H18B	0.8790
C8—H8B	0.9055	C18—H18C	0.8790
C8—H8C	0.9055	N16—H161	0.78 (2)
N6—H61	0.80 (2)	N16—H162	0.83 (2)
N6—H62	0.85 (2)	N17—H171	0.83 (2)
N7—H71	0.84 (2)	N17—H172	0.78 (2)
N7—H72	0.82 (2)	O1—H1	0.73 (3)
N11—C16	1.3548 (19)	O1—H2	0.91 (3)
N11—C12	1.3626 (19)
C6—N1—C2	114.37 (12)	C12—N11—H11	117.5 (14)
N6—C2—N3	117.97 (13)	N16—C12—N13	120.40 (14)
N6—C2—N1	117.21 (14)	N16—C12—N11	118.88 (14)
N3—C2—N1	124.83 (13)	N13—C12—N11	120.72 (13)
C4—N3—C2	115.01 (12)	C12—N13—C14	116.13 (13)
N7—C4—N3	118.48 (13)	N17—C14—N13	118.07 (14)
N7—C4—N5	116.65 (13)	N17—C14—N15	116.57 (13)
N3—C4—N5	124.87 (13)	N13—C14—N15	125.36 (14)
C6—N5—C4	114.82 (12)	C16—N15—C14	115.70 (12)
N5—C6—N1	126.06 (13)	N15—C16—N11	122.13 (14)
N5—C6—C8	116.02 (13)	N15—C16—C18	120.92 (13)
N1—C6—C8	117.92 (14)	N11—C16—C18	116.95 (14)
C6—C8—H8A	109.5	C16—C18—H18A	109.5
C6—C8—H8B	109.5	C16—C18—H18B	109.5
H8A—C8—H8B	109.5	H18A—C18—H18B	109.5
C6—C8—H8C	109.5	C16—C18—H18C	109.5
H8A—C8—H8C	109.5	H18A—C18—H18C	109.5
H8B—C8—H8C	109.5	H18B—C18—H18C	109.5
C2—N6—H61	119.0 (15)	C12—N16—H161	119.4 (15)
C2—N6—H62	119.1 (15)	C12—N16—H162	116.5 (13)
H61—N6—H62	122 (2)	H161—N16—H162	124 (2)
C4—N7—H71	113.2 (13)	C14—N17—H171	120.4 (15)
C4—N7—H72	118.4 (15)	C14—N17—H172	120.1 (16)
H71—N7—H72	128 (2)	H171—N17—H172	119 (2)
C16—N11—C12	119.95 (13)	H1—O1—H2	114 (3)
C16—N11—H11	122.5 (14)
C6—N1—C2—N6	178.21 (14)	C16—N11—C12—N16	179.00 (14)
C6—N1—C2—N3	−1.6 (2)	C16—N11—C12—N13	−0.6 (2)
N6—C2—N3—C4	−179.64 (13)	N16—C12—N13—C14	−179.92 (14)
N1—C2—N3—C4	0.2 (2)	N11—C12—N13—C14	−0.4 (2)
C2—N3—C4—N7	−178.96 (13)	C12—N13—C14—N17	−179.59 (14)
C2—N3—C4—N5	1.7 (2)	C12—N13—C14—N15	0.4 (2)
N7—C4—N5—C6	178.76 (14)	N17—C14—N15—C16	−179.50 (14)
N3—C4—N5—C6	−1.9 (2)	N13—C14—N15—C16	0.5 (2)
C4—N5—C6—N1	0.2 (2)	C14—N15—C16—N11	−1.5 (2)
C4—N5—C6—C8	−179.46 (14)	C14—N15—C16—C18	178.20 (14)
C2—N1—C6—N5	1.4 (2)	C12—N11—C16—N15	1.6 (2)
C2—N1—C6—C8	−178.93 (14)	C12—N11—C16—C18	−178.12 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N6—H61···Cl1^i	0.80 (2)	2.54 (2)	3.3044 (16)	160.4 (19)
N6—H62···Cl1^ii	0.85 (2)	2.63 (2)	3.4265 (16)	157 (2)
N7—H71···N5^iii	0.84 (2)	2.25 (2)	3.082 (2)	174.8 (17)
N7—H72···N15	0.82 (2)	2.47 (2)	3.287 (2)	172.5 (18)
N11—H11···O1	0.83 (2)	1.85 (2)	2.6753 (19)	170.8 (19)
N16—H161···Cl1	0.78 (2)	2.60 (2)	3.2315 (16)	139.6 (19)
N16—H162···N13^ii	0.83 (2)	2.15 (2)	2.983 (2)	176.3 (18)
N17—H171···N3	0.83 (2)	2.12 (2)	2.9368 (19)	169 (2)
N17—H172···Cl1^ii	0.78 (2)	2.49 (2)	3.2328 (16)	160 (2)
O1—H1···N1^iv	0.73 (3)	2.25 (3)	2.9182 (19)	153 (3)
O1—H2···Cl1^v	0.91 (3)	2.40 (3)	3.2881 (19)	165 (2)

Symmetry codes: (i) x, y+1, z+1; (ii) −x, −y+1, −z+1; (iii) −x+1, −y+3, −z+1; (iv) x, y−1, z−1; (v) −x, −y+1, −z.

(II) triaminopyrimidinediium dichloride dihydrate

Crystal data

C4H9N5^2+·2Cl^−·2H2O	F(000) = 488
Mr = 234.09	Dx = 1.467 Mg m^−3
Monoclinic, I2/a	Mo Kα radiation, λ = 0.710689 Å
Hall symbol: -I 2ya'	Cell parameters from 84 reflections
a = 9.4045 (10) Å	θ = 16–21°
b = 8.6089 (9) Å	µ = 0.59 mm^−1
c = 13.7420 (12) Å	T = 298 K
β = 107.742 (10)°	Block, colorless
V = 1059.67 (18) Å^3	0.20 × 0.15 × 0.10 mm
Z = 4

Data collection

Huber CS four-circle diffractometer	1066 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 27.0°, θmin = 2.8°
ω scan	h = 0→11
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
Tmin = 0.891, Tmax = 0.943	l = −17→16
1788 measured reflections	3 standard reflections every 97 reflections
1106 independent reflections	intensity decay: 1%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.070	All H-atom parameters refined
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0413P)^2 + 0.3402P] where P = (Fo^2 + 2Fc^2)/3
1106 reflections	(Δ/σ)max = 0.001
87 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.14 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
N3	0.81645 (11)	0.06971 (11)	0.44232 (7)	0.0351 (2)
H3	0.8550 (18)	0.023 (2)	0.4021 (13)	0.052 (4)*
C2	0.7500	−0.0097 (2)	0.5000	0.0341 (3)
C4	0.81671 (12)	0.22948 (14)	0.43916 (9)	0.0353 (3)
C5	0.7500	0.31123 (19)	0.5000	0.0392 (4)
H5	0.7500	0.427 (3)	0.5000	0.050 (6)*
N6	0.7500	−0.16178 (18)	0.5000	0.0450 (4)
H61	0.7904 (18)	−0.214 (2)	0.4615 (12)	0.053 (5)*
N7	0.88457 (15)	0.29255 (16)	0.37791 (10)	0.0484 (3)
H71	0.918 (2)	0.238 (2)	0.3422 (14)	0.063 (5)*
H72	0.8823 (19)	0.386 (2)	0.3736 (12)	0.052 (4)*
Cl1	0.96356 (4)	−0.05460 (4)	0.28698 (2)	0.05036 (15)
O1	0.84391 (14)	−0.36716 (12)	0.37089 (8)	0.0523 (3)
H1	0.755 (3)	−0.385 (3)	0.3220 (17)	0.088 (7)*
H2	0.894 (3)	−0.319 (3)	0.3407 (19)	0.102 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N3	0.0402 (5)	0.0351 (5)	0.0345 (5)	0.0026 (4)	0.0182 (4)	−0.0018 (4)
C2	0.0342 (7)	0.0341 (7)	0.0331 (7)	0.000	0.0088 (6)	0.000
C4	0.0365 (5)	0.0369 (6)	0.0356 (5)	−0.0001 (4)	0.0153 (4)	0.0026 (4)
C5	0.0480 (9)	0.0308 (8)	0.0454 (9)	0.000	0.0242 (7)	0.000
N6	0.0581 (9)	0.0326 (7)	0.0471 (9)	0.000	0.0201 (7)	0.000
N7	0.0612 (7)	0.0427 (6)	0.0548 (7)	0.0013 (5)	0.0378 (6)	0.0053 (5)
Cl1	0.0494 (2)	0.0601 (2)	0.0483 (2)	0.00133 (13)	0.02482 (15)	−0.01271 (13)
O1	0.0606 (6)	0.0490 (6)	0.0508 (5)	−0.0047 (5)	0.0220 (5)	−0.0038 (4)

Geometric parameters (Å, º)

N3—C2	1.3369 (13)	C5—H5	1.00 (2)
N3—C4	1.3762 (15)	N6—H61	0.867 (16)
N3—H3	0.850 (18)	N7—H71	0.81 (2)
C2—N6	1.310 (2)	N7—H72	0.80 (2)
C4—N7	1.3183 (16)	O1—H1	0.91 (2)
C4—C5	1.3811 (14)	O1—H2	0.83 (3)
C2—N3—C4	122.35 (11)	C4—C5—C4^i	118.73 (15)
C2—N3—H3	120.8 (12)	C4—C5—H5	120.64 (7)
C4—N3—H3	116.7 (12)	C2—N6—H61	121.4 (12)
N6—C2—N3	120.73 (7)	C4—N7—H71	119.8 (14)
N3^i—C2—N3	118.53 (15)	C4—N7—H72	116.8 (13)
N7—C4—N3	115.95 (11)	H71—N7—H72	123.0 (19)
N7—C4—C5	125.04 (12)	H1—O1—H2	105 (2)
N3—C4—C5	118.99 (11)
C4—N3—C2—N6	178.97 (8)	C2—N3—C4—C5	2.03 (16)
C4—N3—C2—N3^i	−1.03 (8)	N7—C4—C5—C4^i	−179.77 (14)
C2—N3—C4—N7	−179.06 (10)	N3—C4—C5—C4^i	−0.96 (7)

Symmetry code: (i) −x+3/2, y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···Cl1	0.850 (18)	2.230 (18)	3.0686 (11)	169.0 (16)
N6—H61···O1	0.867 (16)	1.979 (16)	2.8301 (14)	166.8 (16)
N7—H71···Cl1	0.81 (2)	2.70 (2)	3.4074 (14)	147.0 (17)
N7—H71···Cl1^ii	0.81 (2)	2.967 (19)	3.2983 (12)	107.2 (15)
N7—H72···O1^iii	0.80 (2)	2.16 (2)	2.9521 (18)	170.4 (18)
O1—H1···Cl1^iv	0.91 (2)	2.21 (2)	3.1143 (13)	175 (2)
O1—H2···Cl1	0.83 (3)	2.53 (3)	3.2599 (12)	146 (2)

Symmetry codes: (ii) −x+2, y+1/2, −z+1/2; (iii) x, y+1, z; (iv) −x+3/2, −y−1/2, −z+1/2.