The chloride, bromide and iodide salts of 1-(diamino­methyl­ene)thio­uron-1-ium

Crystals of 1-(diamino­methyl­ene)thio­uron-1-ium chloride, C₂H₇N₄S⁺·Cl^-, 1-(diamino­methyl­ene)thio­uron-1-ium bromide, C₂H₇N₄S⁺·Br^-, and 1-(diamino­methyl­ene)thio­uron-1-ium iodide, C₂H₇N₄S⁺·I^-, are built up from the nonplanar 1-(di­amino­methyl­ene)thio­uron-1-ium cation and the respective halogenide anion. The conformation of the 1-(diamino­methyl­ene)thio­uron-1-ium cation in each case is twisted. Both arms of the cation are planar and rotated in opposite directions around the C-N bonds involving the central N atom. The dihedral angles describing the twisted conformation are 22.9 (1), 15.2 (1) and 4.2 (1)° in the chloride, bromide and iodide salts, respectively. Ionic and extensive hydrogen-bonding inter­actions join oppositely charged units into a supra­molecular network. The aim of the investigation is to study the influence of the size of the ionic radii of the Cl^-, Br^- and I^- ions on the dimensionality of the hydrogen-bonding network of the 1-(diamino­methyl­ene)thio­uron-1-ium cation. The 1-(diamino­methyl­ene)thio­uron-1-ium system should be of use in crystal engin­eering to form multidimensional networks.

S1. Comment

The oresent work continues our investigations of the characterization of the compounds that in solids form multiple hydrogen-bonding systems (Janczak & Perpétuo, 2008a; Perpétuo & Janczak, 2007, 2008; Janczak & Kubiak, 2005a,b). Previously, we have investigated the crystal structure of commercially available 2-imino-4-thiobiuret (Aldrich, CAS No. 2114–02–05) and stated that it exists in the tautomeric form, i.e. 1-(diaminomethylene)thiourea (Janczak & Perpétuo, 2008b). 2-Iminio-4-thiourea and its tautomer have several potential coordinating modes, since they can act as N,N- or N,S-donor ligands and can form several different complexes with metal ions. The coordination of metals by this ligand is possible by either the neutral or a deprotonated (anionic) form. A search of the Cambridge Structural Database (Version 5.29 of November 2007; Allen, 2002) for structures containing this ligand yielded only three structures of Pt complexes in which Pt is coordinated by 2-imino-4-thiobiuret or its deprotonated form (Doxiadi et al., 2003). Besides these known Pt complexes with neutral and deproronated negatively charged ligands, 2-iminio-4-thiobiuret and its tautomer [i.e. 1-(diaminomethylene)thiourea] can form salts, since they contain an N atom with a lone pair of electron, which can accept an H atom forming a positively charged C₂H₇N₄S⁺ unit. In the present work, we investigate the crystal structures of three salts, namely 1-(diaminomethylene)thiouron-1-ium chloride, (Ia), bromide, (Ib), and iodide, (Ic). In addition the X-ray geometry and the conformation of the protonated C₂H₇N₄S⁺ cation is compared with that in the gas-phase, as predicted for an isolated cation by density functional theory (Frisch et al., 1998), as well as with the geometry of the neutral C₂H₆N₄S molecule reported previously (Janczak & Perpétuo, 2008b). Ab-initio molecular orbital (MO) calculations were performed at the B3LYP/6–31+G* level and the results are illustrated in Fig. 1.

The asymmetric units of the title salts are illustrated in Fig. 2. The geometry of the 1-(diaminomethylene)thiouron-1-ium cation in these salts is not planar. However, both arms of the cation, containing atoms N1, C2, N3 and N4, and atoms N1, C1, N2 and S1, are planar. The deviations of the non-H atoms from these planes are smaller than 0.029 (2) and 0.014 (2) Å, respectively. The two arms of the cation are oppositely turned around the C—N bonds involving the central N1 atom. Thus the conformation of the 1-(diaminomethylene)thiouron-1-ium cation is twisted. The dihedral angles between the planes are 22.9 (1), 15.2 (1) and 4.2 (1)° in the chloride, bromide and iodide salts, respectively. The rotation angles correlate with the electronegativity of the halogen: 3.16 for Cl, 2.96 for Br and 2.66 for I (Pauling, 1960). A similar twisted conformation is observed in the crystal structure of neutral 1-(diaminomethylene)thiourea [22.2 (1)°; Janczak & Perpétuo, 2008b]. The gas-phase conformation of the 1-(diaminomethylene)thiouron-1-ium cation as shown by ab-initio MO calculations is also twisted, with a dihedral angle of 6.2°. The difference between the conformation of the cation in the crystal and in the gas phase results from the interionic and hydrogen-bonding interactions present in the crystals.

In the present salts, the respective C—N and C═S bond lengths are essentially the same. The C—N bond lengths involving the central N1 atom are significantly longer than the other C—N bond lengths linking the amine groups (Tables 1, 3 and 5). The C1═S1 bond lengths in these salts are comparable to those in thiourea derivatives (where the average C═S distance is 1.663 Å; Allen et al. 1997). However the gas-phase data for thioformaldehyde, CH₂═S, give for the C═S bond distance a value of 1.6109 (8) Å, which represents 100% double-bond character (Johnson et al., 1971), while C═S bond lengths of ca 1.74 Å are cited as representing 50% double-bond character, as observed in dithiolate anions (Abrahams, 1956; Allen et al., 1987). The planarity of the amine groups indicates the sp²-hybridization of the orbitals on the amine N atoms, and the lone pair of electrons occupies the p orbital, which is perpendicular to the plane of the NH₂ groups. The p orbitals of the C and S atoms, forming the π bonds of the C2═N1 and C1═S1 double bonds, are also perpendicular to the plane; therefore, partial delocalization, due to the symmetry of the p orbitals, of the π electrons over whole cation is possible, and leads to elongation of the C1═S1 and C2═N1 double bonds and to shortening of the other single C—N bonds (Table 1, 3 and 5). Thus, the bond order of C1═ S1 and C2═N1 is smaller than 2, and the bond order of the C—N bonds linking the amine groups is greater than 1. The bond order of the C—N bonds joining the amine groups is greater than the bond order of the C—N bonds involved the central N1 atom. The repulsion between the S atom and the amine group at N4 causes the rotation of both arms of the cation around the C—N1 bonds and is responsible for the twisted conformation of the cation. This interaction decreases the overlapping of the p orbitals of atoms C2 and N1 and of atoms N1 and C1, and leads to the elongation of the C2—N1 and N1—C1 bonds compared with the other C—N_amine bonds, in which the overlapping of the p orbitals is more effective. The steric interaction between atom S1 and amine atom N4 is also responsible for the distortion of the N—C—N, C—N1—C and N—C1—S1 angles, as expected for sp²-hybridization. A similar correlation between the bond lengths and angles can be found in the gas-phase structure as obtained by ab-initio MO calculations (Fig. 1). The protonation of the central N1 atom leads to a decrease of the steric effect of the lone pair of electron on atom N1 and makes the C2—N1—C1 angle greater by \sim 6° in relation to that in the neutral diaminomethylenethiourea molecule (Janczak & Perpétuo, 2008b). This is consistent with the valence-shell electron-pair repulsion model (Gillespie, 1963, 1992), according to which the lone pair of electrons on the N atom occupies a wider region than the bonding pair N—H.

In the crystal structures, besides the interionic interactions, the oppositely charged units are linked by hydrogen bonds. In the crystal structure of (Ia), the 1-(diaminomethylene)thiouron-1-ium cations are arranged almost parallel to the (100) crystallographic plane, forming layers with a distance of a/2 (~3.26 Å) between the layers (Fig. 3a). Within the layers, as well as between the layers, the cations are interconnected by N—H···Cl hydrogen bonds (Table 2). In the crystal structures of both (Ib) and (Ic), C₂H₇N₄S⁺ cations related by an inversion center interact via N—H···S hydrogen bonds, forming a dimeric structure (Figs. 2b and 2c). The S atom contains two lone pairs of electrons that can be involved in hydrogen bonds as acceptors. The non-bonded S···H contact requires that the distance between the S and H atoms should be less than the sum of the van der Waals radii of S and H atoms [r_S = 1.80 Å (Bondi, 1964) and r_H = 1.10 Å (Rowland & Taylor, 1996)]. S···H contacts shorter than 2.90 Å are observed in both (Ib) and (Ic) (Tables 4 and 6). The dimers of C₂H₇N₄S⁺ cations in (Ib) are interconnected by N—H···Br hydrogen bonds, forming layers that lie almost parallel to the (102) plane and are separated by a distance of ~3.16 Å. No hydrogen bonds of the Br···H type with a distance shorter than the sum of the van der Waals radii of Br and H (r_Br=1.81 and r_H=1.10 Å; Rowland & Taylor, 1996; Pauling, 1960) were found between the layers; therefore, they interact only by the van der Waals forces. In the crystal structure of (Ic), the dimers interact via N—H···I hydrogen bonds, forming layers almost parallel to (302). Similarly to the crystal structure of (Ib), there are no I···H contacts with a distance shorter than the sum of the van der Waals radii of I and H (r_I = 2.20 Å; Pauling, 1960).

This study underscores the utility of 1-(diaminomethylene)thiourea for developing supramolecular structures with acids. The larger anions, such as Br^- and I^- , interconnect the 1-(diaminomethylene)thiouron-1-ium dimers into layers. The large anionic radii cause the layers to be separated by a greater distance than the sum of van der Waals radii of I or Br and H atoms, and therefore there are no hydrogen-bonding interactions between the layers in (Ib) and (Ic). However, in the chloride salt, the smaller chloride anions link the 1-(diaminomethylene)thiouron-1-ium cations into layers that are interconnected via Cl···H interactions into a three-dimensional network.

Related literature

For related literature, see: Abrahams (1956); Allen (2002); Allen et al. (1987, 1997); Bondi (1964); Doxiadi et al. (2003); Frisch et al. (1998); Gillespie (1963, 1992); Janczak & Kubiak (2005a, 2005b); Janczak & Perpétuo (2008a, 2008b); Johnson et al. (1971); Pauling (1960); Perpétuo & Janczak (2007, 2008); Rowland & Taylor (1996).

S2. Experimental

Suitable crystals of (Ia), (Ib) and (Ic) were obtained from 2-imino-4-thiobiuret (purchased from Aldrich) dissolved in 5% aqueous solutions of HCl, HBr and HI. [Quantities? reaction conditions?]

S3. Refinement

The H atoms were located from difference Fourier maps and and their positions refined.

Computing details

For all compounds, data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis CCD (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. Results of the optimized molecular orbital calculations (B3LYP/6–31+G*) for the 1-(diaminomethylene)thiouronium cation (Å, °).
	Fig. 2. Views of (a) (Ia), (b) (Ib) and (c) (Ic), with the atom-labelling schemes. Displacement ellipsoids are shown at the 50% probability level and H atoms as spheres of arbitrary radii.
	Fig. 3. Views of the crystal packing in (Ia), (Ib) and (Ic), showing the hydrogen-bonded three-dimensional network in (Ia) (a), and the hydrogen-bonded layers in (Ib) (b) and (Ic) (c). Dashed lines represent hydrogen bonds.

(Ia) 1-(diaminomethylene)thiouron-1-ium chloride

Crystal data

C2H7N4S^+·Cl^−	F(000) = 320
Mr = 154.63	Dx = 1.567 Mg m^−3 Dm = 1.56 Mg m^−3 Dm measured by flotation
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 562 reflections
a = 6.517 (1) Å	θ = 2.8–28.4°
b = 6.807 (1) Å	µ = 0.80 mm^−1
c = 14.777 (3) Å	T = 295 K
β = 90.36 (2)°	Paralellepiped, colourless
V = 655.51 (19) Å^3	0.37 × 0.22 × 0.17 mm
Z = 4

Data collection

Kuma KM-4 with area CCD detector diffractometer	1635 independent reflections
Radiation source: fine-focus sealed tube	1164 reflections with σ > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 1024x1024 with blocks 2x2 pixels mm^-1	θmax = 28.4°, θmin = 2.8°
ω–scan	h = −8→8
Absorption correction: analytical (face-indexed; SHELXTL; Sheldrick, 2008)	k = −9→8
Tmin = 0.760, Tmax = 0.878	l = −18→19
6665 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.030	Only H-atom coordinates refined
wR(F^2) = 0.062	w = 1/[σ^2(Fo^2) + (0.0275P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max < 0.001
1635 reflections	Δρmax = 0.21 e Å^−3
95 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.041 (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
Cl1	0.51493 (6)	0.72135 (7)	0.41465 (3)	0.04362 (16)
S1	0.89198 (7)	0.05688 (7)	0.26804 (3)	0.03941 (16)
C1	0.7581 (2)	0.2129 (2)	0.33105 (10)	0.0295 (4)
N1	0.8064 (2)	0.2597 (2)	0.42000 (9)	0.0339 (4)
H1	0.719 (3)	0.302 (3)	0.4489 (12)	0.041*
C2	0.9855 (2)	0.2404 (2)	0.46644 (10)	0.0293 (4)
N2	0.5888 (2)	0.3002 (3)	0.30276 (11)	0.0444 (4)
H21	0.532 (3)	0.393 (3)	0.3335 (12)	0.053*
H22	0.553 (3)	0.277 (3)	0.2486 (14)	0.053*
N3	0.9824 (3)	0.2867 (3)	0.55275 (10)	0.0402 (4)
H31	0.869 (3)	0.304 (3)	0.5781 (13)	0.048*
H32	1.084 (3)	0.269 (3)	0.5815 (13)	0.048*
N4	1.1546 (2)	0.1858 (3)	0.42755 (11)	0.0436 (4)
H41	1.150 (3)	0.147 (3)	0.3760 (13)	0.052*
H42	1.268 (3)	0.190 (3)	0.4549 (13)	0.052*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0321 (2)	0.0687 (4)	0.0300 (2)	−0.0027 (2)	−0.00419 (17)	−0.0038 (2)
S1	0.0482 (3)	0.0429 (3)	0.0271 (2)	0.0086 (2)	−0.00226 (18)	−0.00554 (19)
C1	0.0305 (8)	0.0304 (10)	0.0277 (8)	−0.0028 (7)	−0.0030 (7)	0.0011 (7)
N1	0.0267 (7)	0.0491 (10)	0.0260 (7)	0.0046 (7)	−0.0007 (6)	−0.0085 (6)
C2	0.0292 (8)	0.0306 (10)	0.0281 (8)	−0.0040 (7)	−0.0036 (7)	0.0023 (7)
N2	0.0452 (9)	0.0523 (11)	0.0354 (8)	0.0157 (8)	−0.0129 (7)	−0.0094 (8)
N3	0.0375 (8)	0.0553 (11)	0.0277 (8)	−0.0032 (9)	−0.0053 (6)	−0.0007 (7)
N4	0.0278 (8)	0.0638 (12)	0.0389 (8)	0.0025 (8)	−0.0059 (7)	−0.0103 (8)

Geometric parameters (Å, º)

S1—C1	1.6636 (17)	N2—H21	0.86 (2)
C1—N2	1.319 (2)	N2—H22	0.85 (2)
C1—N1	1.3866 (19)	N3—H31	0.84 (2)
N1—C2	1.3565 (19)	N3—H32	0.79 (2)
N1—H1	0.773 (17)	N4—H41	0.806 (19)
C2—N4	1.300 (2)	N4—H42	0.844 (19)
C2—N3	1.314 (2)
N2—C1—N1	112.45 (15)	C1—N2—H21	121.5 (13)
N2—C1—S1	123.43 (12)	C1—N2—H22	116.1 (13)
N1—C1—S1	124.07 (12)	H21—N2—H22	121.2 (18)
C2—N1—C1	130.32 (14)	C2—N3—H31	119.1 (13)
C2—N1—H1	113.2 (14)	C2—N3—H32	117.8 (14)
C1—N1—H1	116.5 (14)	H31—N3—H32	121.0 (19)
N4—C2—N3	121.03 (15)	C2—N4—H41	118.8 (14)
N4—C2—N1	122.20 (15)	C2—N4—H42	121.5 (13)
N3—C2—N1	116.73 (15)	H41—N4—H42	119.6 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1^i	0.773 (17)	2.539 (18)	3.2305 (16)	149.9 (18)
N2—H21···Cl1	0.86 (2)	2.54 (2)	3.3458 (18)	156.0 (16)
N2—H22···Cl1^ii	0.85 (2)	2.48 (2)	3.3225 (18)	174.2 (18)
N3—H31···Cl1^i	0.84 (2)	2.51 (2)	3.2804 (18)	152.9 (17)
N3—H32···Cl1^iii	0.79 (2)	2.62 (2)	3.3084 (18)	146.9 (18)
N4—H41···S1	0.806 (19)	2.390 (19)	3.0339 (17)	137.5 (18)
N4—H42···Cl1^iii	0.844 (19)	2.46 (2)	3.2268 (17)	152.2 (17)

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

(Ib) 1-(diaminomethylene)thiouron-1-ium bromide

Crystal data

C2H7N4S^+·Br^−	Z = 2
Mr = 199.09	F(000) = 196
Triclinic, P1	Dx = 1.921 Mg m^−3 Dm = 1.92 Mg m^−3 Dm measured by flotation
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.9661 (9) Å	Cell parameters from 827 reflections
b = 7.4841 (17) Å	θ = 3.4–29.4°
c = 9.5739 (19) Å	µ = 6.18 mm^−1
α = 94.220 (14)°	T = 295 K
β = 90.091 (11)°	Paralellepiped, colourless
γ = 104.012 (15)°	0.32 × 0.22 × 0.16 mm
V = 344.23 (12) Å^3

Data collection

Kuma KM-4 with area CCD detector diffractometer	1737 independent reflections
Radiation source: fine-focus sealed tube	1295 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.017
Detector resolution: 1024x1024 with blocks 2x2 pixels mm^-1	θmax = 29.4°, θmin = 3.4°
ω–scan	h = −5→6
Absorption correction: analytical (face-indexed; SHELXTL; Sheldrick, 2008)	k = −9→9
Tmin = 0.244, Tmax = 0.441	l = −12→12
4034 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Only H-atom coordinates refined
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.0481P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max = 0.005
1737 reflections	Δρmax = 0.76 e Å^−3
95 parameters	Δρmin = −0.51 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.079 (6)

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
Br1	0.78860 (7)	0.69979 (4)	0.10439 (3)	0.05125 (18)
S1	0.1687 (2)	0.25428 (13)	0.48486 (9)	0.0536 (3)
C1	0.2765 (6)	0.3567 (4)	0.3381 (3)	0.0370 (6)
N1	0.4595 (6)	0.3053 (4)	0.2455 (3)	0.0464 (6)
H1	0.545 (8)	0.397 (5)	0.196 (4)	0.056*
N2	0.1940 (7)	0.5028 (4)	0.3028 (3)	0.0540 (7)
H21	0.244 (8)	0.554 (5)	0.230 (4)	0.065*
H22	0.067 (8)	0.542 (5)	0.366 (4)	0.065*
C2	0.5473 (6)	0.1463 (4)	0.2300 (3)	0.0407 (7)
N3	0.7246 (8)	0.1378 (5)	0.1304 (4)	0.0591 (8)
H31	0.782 (8)	0.049 (6)	0.118 (4)	0.071*
H32	0.777 (8)	0.236 (5)	0.080 (4)	0.071*
N4	0.4618 (6)	0.0105 (4)	0.3068 (3)	0.0546 (8)
H41	0.549 (8)	−0.092 (6)	0.289 (4)	0.066*
H42	0.357 (9)	0.033 (6)	0.368 (4)	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0621 (3)	0.0501 (3)	0.0452 (2)	0.01754 (17)	0.00881 (15)	0.01380 (15)
S1	0.0645 (6)	0.0557 (5)	0.0500 (5)	0.0273 (4)	0.0219 (4)	0.0213 (4)
C1	0.0341 (14)	0.0353 (15)	0.0425 (15)	0.0090 (12)	0.0044 (12)	0.0059 (13)
N1	0.0595 (17)	0.0462 (15)	0.0403 (14)	0.0219 (13)	0.0146 (12)	0.0159 (12)
N2	0.068 (2)	0.0515 (17)	0.0526 (17)	0.0297 (15)	0.0117 (15)	0.0176 (14)
C2	0.0427 (16)	0.0420 (16)	0.0390 (15)	0.0141 (13)	0.0008 (13)	0.0016 (13)
N3	0.070 (2)	0.0545 (19)	0.0586 (18)	0.0255 (17)	0.0214 (15)	0.0063 (15)
N4	0.0586 (19)	0.0464 (16)	0.064 (2)	0.0213 (15)	0.0182 (15)	0.0113 (15)

Geometric parameters (Å, º)

S1—C1	1.676 (3)	C2—N4	1.286 (4)
C1—N2	1.322 (4)	C2—N3	1.308 (4)
C1—N1	1.372 (4)	N3—H31	0.79 (4)
N1—C2	1.362 (4)	N3—H32	0.90 (4)
N1—H1	0.89 (4)	N4—H41	0.97 (4)
N2—H21	0.83 (4)	N4—H42	0.82 (4)
N2—H22	0.96 (4)
N2—C1—N1	113.0 (3)	N4—C2—N3	121.2 (3)
N2—C1—S1	121.6 (2)	N4—C2—N1	123.0 (3)
N1—C1—S1	125.4 (2)	N3—C2—N1	115.9 (3)
C2—N1—C1	130.2 (3)	C2—N3—H31	119 (3)
C2—N1—H1	117 (2)	C2—N3—H32	117 (3)
C1—N1—H1	112 (2)	H31—N3—H32	123 (4)
C1—N2—H21	123 (3)	C2—N4—H41	115 (2)
C1—N2—H22	114 (2)	C2—N4—H42	113 (3)
H21—N2—H22	123 (4)	H41—N4—H42	132 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br1	0.89 (4)	2.51 (4)	3.387 (3)	167 (3)
N2—H21···Br1	0.83 (4)	2.95 (4)	3.580 (4)	134 (3)
N2—H22···S1^i	0.96 (4)	2.50 (4)	3.426 (3)	161 (3)
N3—H31···Br1^ii	0.79 (4)	2.61 (4)	3.361 (3)	159 (4)
N3—H32···Br1^iii	0.90 (4)	2.76 (4)	3.372 (4)	126 (3)
N4—H41···Br1^ii	0.97 (4)	2.73 (4)	3.601 (3)	149 (3)
N4—H42···S1	0.82 (4)	2.32 (4)	3.031 (3)	147 (4)

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

(Ic) 1-(diaminomethylene)thiouron-1-ium iodide

Crystal data

C2H7N4S^+·I^−	F(000) = 464
Mr = 246.08	Dx = 2.153 Mg m^−3 Dm = 2.15 Mg m^−3 Dm measured by flotation
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 876 reflections
a = 10.929 (3) Å	θ = 3.3–29.0°
b = 7.875 (1) Å	µ = 4.41 mm^−1
c = 9.456 (2) Å	T = 295 K
β = 111.10 (1)°	Paralellepiped, colourless
V = 759.3 (3) Å^3	0.38 × 0.24 × 0.22 mm
Z = 4

Data collection

Kuma KM-4 with area CCD detector diffractometer	2001 independent reflections
Radiation source: fine-focus sealed tube	1785 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.013
Detector resolution: 1024x1024 with blocks 2x2 pixels mm^-1	θmax = 29.0°, θmin = 3.3°
ω–scan	h = −14→14
Absorption correction: analytical (face-indexed; SHELXTL; Sheldrick, 2008)	k = −10→10
Tmin = 0.286, Tmax = 0.445	l = −9→12
10077 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.021	Only H-atom coordinates refined
wR(F^2) = 0.055	w = 1/[σ^2(Fo^2) + (0.0332P)^2 + 0.3719P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.004
2001 reflections	Δρmax = 0.81 e Å^−3
95 parameters	Δρmin = −0.68 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0257 (9)

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
I1	0.373664 (15)	0.34350 (2)	0.591594 (16)	0.04108 (9)
S1	0.04026 (6)	0.76529 (8)	0.09361 (7)	0.04611 (16)
C1	0.1532 (2)	0.6433 (3)	0.2193 (3)	0.0327 (4)
N1	0.2498 (2)	0.7006 (3)	0.3494 (2)	0.0386 (4)
H1	0.293 (3)	0.627 (4)	0.411 (4)	0.046*
N2	0.1595 (3)	0.4770 (3)	0.2012 (3)	0.0462 (5)
H21	0.215 (3)	0.414 (5)	0.268 (4)	0.055*
H22	0.106 (3)	0.428 (4)	0.123 (4)	0.055*
C2	0.2737 (2)	0.8575 (3)	0.4123 (3)	0.0343 (4)
N3	0.3736 (2)	0.8725 (4)	0.5399 (3)	0.0520 (6)
H31	0.386 (3)	0.964 (6)	0.586 (4)	0.062*
H32	0.420 (4)	0.797 (5)	0.575 (4)	0.062*
N4	0.1994 (2)	0.9890 (3)	0.3521 (3)	0.0455 (5)
H41	0.220 (3)	1.083 (5)	0.392 (4)	0.055*
H42	0.140 (3)	0.978 (4)	0.269 (4)	0.055*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.04361 (12)	0.03428 (11)	0.03844 (12)	−0.00127 (5)	0.00640 (7)	0.00020 (5)
S1	0.0429 (3)	0.0382 (3)	0.0424 (3)	0.0049 (2)	−0.0025 (3)	−0.0033 (2)
C1	0.0342 (10)	0.0313 (10)	0.0334 (10)	−0.0004 (8)	0.0132 (9)	−0.0031 (8)
N1	0.0386 (10)	0.0320 (9)	0.0365 (10)	0.0079 (8)	0.0029 (8)	−0.0025 (8)
N2	0.0548 (13)	0.0310 (9)	0.0420 (11)	−0.0001 (9)	0.0045 (10)	−0.0022 (8)
C2	0.0343 (10)	0.0360 (11)	0.0326 (10)	−0.0022 (8)	0.0120 (9)	−0.0037 (8)
N3	0.0427 (12)	0.0492 (13)	0.0489 (13)	0.0041 (10)	−0.0020 (10)	−0.0180 (11)
N4	0.0558 (13)	0.0286 (9)	0.0422 (11)	−0.0003 (9)	0.0056 (10)	−0.0039 (8)

Geometric parameters (Å, º)

S1—C1	1.674 (2)	C2—N3	1.309 (3)
C1—N2	1.326 (3)	C2—N4	1.312 (3)
C1—N1	1.377 (3)	N3—H31	0.83 (4)
N1—C2	1.355 (3)	N3—H32	0.78 (4)
N1—H1	0.84 (3)	N4—H41	0.82 (4)
N2—H21	0.86 (4)	N4—H42	0.82 (3)
N2—H22	0.85 (4)
N2—C1—N1	112.3 (2)	N3—C2—N4	120.6 (2)
N2—C1—S1	122.29 (19)	N3—C2—N1	116.9 (2)
N1—C1—S1	125.36 (16)	N4—C2—N1	122.5 (2)
C2—N1—C1	130.9 (2)	C2—N3—H31	119 (2)
C2—N1—H1	111 (2)	C2—N3—H32	122 (3)
C1—N1—H1	117 (2)	H31—N3—H32	119 (4)
C1—N2—H21	122 (2)	C2—N4—H41	119 (2)
C1—N2—H22	121 (2)	C2—N4—H42	119 (2)
H21—N2—H22	117 (3)	H41—N4—H42	122 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···I1	0.84 (3)	2.75 (3)	3.571 (2)	165 (3)
N2—H21···I1	0.86 (4)	2.98 (4)	3.741 (3)	149 (3)
N2—H22···S1^i	0.85 (4)	2.59 (4)	3.434 (2)	171 (3)
N3—H31···I1^ii	0.83 (4)	2.99 (5)	3.741 (3)	151 (3)
N4—H41···I1^ii	0.82 (4)	2.88 (4)	3.667 (2)	160 (3)
N4—H42···S1	0.82 (3)	2.33 (3)	3.007 (2)	140 (3)

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