The structures of the first two organic carboxylate salts of 1-(diaminomethylene)thiourea (HATU), namely 1-(diaminomethylene)thiouron-1-ium formate, C2H7N4S+·HCOO-, (I), and bis[1-(diaminomethylene)thiouron-1-ium] oxalate dihydrate, 2C2H7N4S+·C2O42-·2H2O, (II), in which the oxalate lies on a symmetry centre, possess different extended hydrogen-bonding networks with different graph-set motifs. The R22(8) motif present in (I) does not appear in (II), but an R21(6) motif is present in both (I) and (II). Compound (I) has a three-dimensional hydrogen-bonding network, whereas (II) has a layered structure with layers joined by hydrogen-bonding motifs that form R42(8) patterns. This work extends the known supramolecular structural data for HATU to include these organic carboxylates in addition to the previously characterized salts with inorganic acids.
Supporting information
CCDC references: 746090; 746091
For the preparation of (I), HATU (0.05 g) was dissolved in an excess of 5%
formic acid. On slow evaporation of the solution, crystals of (I) in the form
of colourless plates were obtained. A similar procedure using acetic acid
instead of formic acid yields crystals of the isomorphous acetate salt
[a = 11.978 (4), b = 6.208 (3), c = 11.753 (4) Å, β =
116.57 (3)°, P21/c].
For the preparation of (II), HATU (0.5 g) was dissolved in water (10 ml). A
stoichiometric amount of oxalic acid dihydrate was dissolved in water (15 ml).
The two solutions were combined to yield a white crystalline precipitate. The
mixture obtained was allowed to stand for a week for slow recrystallization. A
single-crystal in the form of a colourless polyhedron was chosen from the
precipitate.
All H atoms were found in difference Fourier maps. For (I), the formate H atom
was refined as riding on its parent C atom. The remaining H atoms bonded to N
atoms were first refined with restraints (DFIX; Sheldrick,
2008), with
N—H = 0.870 (2) Å, and subsequently constrained as riding (AFIX 3) [All
H atoms in CIF tables for (I) have freely refined Uiso
values - please clarify]. The highest final difference Fourier peak of
0.28 e Å-3 is located 0.78 Å from atom C1 and 0.91 Å from atom S1. In
the case of (II), H-atom parameters were refined freely. In the final
difference Fourier map, the highest peak of 0.44 e Å-3 was located on the
oxalate C—C bond (0.79 Å from atom C10).
For both compounds, data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (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, 2005) and SHELXTL-NT (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
(I) 1-(diaminomethylene)thiouron-1-ium formate
top
Crystal data top
C2H7N4S+·CHO2− | F(000) = 344 |
Mr = 164.19 | Dx = 1.496 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2935 reflections |
a = 12.693 (4) Å | θ = 3.5–28.6° |
b = 5.509 (3) Å | µ = 0.39 mm−1 |
c = 11.576 (4) Å | T = 100 K |
β = 115.80 (3)° | Plate, colourless |
V = 728.8 (5) Å3 | 0.19 × 0.14 × 0.04 mm |
Z = 4 | |
Data collection top
Kuma KM4 CCD area-detector diffractometer | 1774 independent reflections |
Radiation source: fine-focus sealed tube | 1336 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.044 |
ω scans | θmax = 28.6°, θmin = 3.5° |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | h = −16→16 |
Tmin = 0.955, Tmax = 0.981 | k = −7→7 |
6097 measured reflections | l = −13→14 |
Refinement top
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)] = 0.045 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.108 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | w = 1/[σ2(Fo2) + (0.060P)2] where P = (Fo2 + 2Fc2)/3 |
1774 reflections | (Δ/σ)max < 0.001 |
99 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
Crystal data top
C2H7N4S+·CHO2− | V = 728.8 (5) Å3 |
Mr = 164.19 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.693 (4) Å | µ = 0.39 mm−1 |
b = 5.509 (3) Å | T = 100 K |
c = 11.576 (4) Å | 0.19 × 0.14 × 0.04 mm |
β = 115.80 (3)° | |
Data collection top
Kuma KM4 CCD area-detector diffractometer | 1774 independent reflections |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | 1336 reflections with I > 2σ(I) |
Tmin = 0.955, Tmax = 0.981 | Rint = 0.044 |
6097 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.108 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | Δρmax = 0.28 e Å−3 |
1774 reflections | Δρmin = −0.20 e Å−3 |
99 parameters | |
Special details top
Experimental. IR spectrum was collected on a Bruker spectrometer for a sample suspended in
Nujol mull (KBr windows). (I): 424.5 (w), 436.0 (w), 490.9 (w), 547.4
(m), 617.1 (m), 669.9 (w), 737.2 (m), 774.5 (m),
821.5 (w), 888.9 (vw), 989.8 (vw), 1097.6 (m), 1180.6 (m), 1332.1
(vs), 1354.3 (s), 1381.0 (s), 1413.8 (m), 1464.6
(s), 1521.7 (s), 1594.8 (vs), 1713.6 (s), 2738.9
(s), 2854.5 (vs), 2924.2 (vs), 3220.8 (vs) |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C10 | 0.59229 (19) | 0.2747 (4) | 0.5572 (2) | 0.0213 (5) | |
H10 | 0.5550 | 0.1645 | 0.4881 | 0.038 (7)* | |
O1 | 0.68204 (13) | 0.3827 (3) | 0.56317 (14) | 0.0234 (4) | |
O2 | 0.54835 (13) | 0.2994 (3) | 0.63342 (14) | 0.0250 (4) | |
S1 | 0.94571 (5) | 1.19873 (11) | 0.84467 (5) | 0.02242 (18) | |
C1 | 0.85516 (18) | 1.1867 (4) | 0.9164 (2) | 0.0191 (5) | |
N1 | 0.76401 (15) | 1.0245 (3) | 0.88731 (17) | 0.0190 (4) | |
H1 | 0.7237 | 1.0405 | 0.9314 | 0.031 (7)* | |
N3 | 0.63657 (15) | 0.7091 (4) | 0.79700 (17) | 0.0231 (4) | |
H31 | 0.5998 | 0.7558 | 0.8414 | 0.031 (7)* | |
H32 | 0.6130 | 0.5836 | 0.7465 | 0.042 (8)* | |
C2 | 0.72944 (18) | 0.8301 (4) | 0.8053 (2) | 0.0184 (5) | |
N2 | 0.86412 (17) | 1.3394 (3) | 1.00847 (17) | 0.0220 (4) | |
H21 | 0.8193 | 1.3187 | 1.0470 | 0.021 (6)* | |
H22 | 0.9182 | 1.4503 | 1.0385 | 0.027 (7)* | |
N4 | 0.78502 (17) | 0.7640 (3) | 0.73713 (18) | 0.0241 (5) | |
H41 | 0.8479 | 0.8483 | 0.7536 | 0.045 (8)* | |
H42 | 0.7588 | 0.6372 | 0.6882 | 0.033 (7)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C10 | 0.0227 (12) | 0.0202 (12) | 0.0229 (11) | 0.0007 (9) | 0.0119 (10) | 0.0015 (9) |
O1 | 0.0221 (8) | 0.0275 (9) | 0.0250 (8) | −0.0039 (7) | 0.0143 (7) | −0.0015 (7) |
O2 | 0.0250 (9) | 0.0268 (9) | 0.0299 (9) | −0.0006 (7) | 0.0181 (8) | 0.0016 (7) |
S1 | 0.0223 (3) | 0.0285 (3) | 0.0208 (3) | −0.0014 (3) | 0.0134 (2) | −0.0004 (2) |
C1 | 0.0188 (11) | 0.0214 (11) | 0.0169 (10) | 0.0043 (9) | 0.0076 (9) | 0.0043 (9) |
N1 | 0.0177 (9) | 0.0237 (10) | 0.0191 (9) | 0.0021 (8) | 0.0113 (8) | −0.0001 (7) |
N3 | 0.0221 (10) | 0.0265 (10) | 0.0259 (10) | −0.0003 (9) | 0.0154 (9) | −0.0043 (9) |
C2 | 0.0187 (11) | 0.0181 (11) | 0.0183 (10) | 0.0035 (9) | 0.0080 (9) | 0.0032 (9) |
N2 | 0.0246 (10) | 0.0248 (11) | 0.0230 (10) | −0.0043 (9) | 0.0162 (9) | −0.0046 (8) |
N4 | 0.0284 (11) | 0.0235 (11) | 0.0289 (10) | −0.0035 (9) | 0.0205 (9) | −0.0054 (8) |
Geometric parameters (Å, º) top
C10—O2 | 1.240 (3) | N3—C2 | 1.321 (3) |
C10—O1 | 1.260 (3) | N3—H31 | 0.8699 |
C10—H10 | 0.9500 | N3—H32 | 0.8700 |
S1—C1 | 1.686 (2) | C2—N4 | 1.318 (3) |
C1—N2 | 1.324 (3) | N2—H21 | 0.8700 |
C1—N1 | 1.383 (3) | N2—H22 | 0.8702 |
N1—C2 | 1.370 (3) | N4—H41 | 0.8701 |
N1—H1 | 0.8698 | N4—H42 | 0.8696 |
| | | |
O2—C10—O1 | 125.8 (2) | H31—N3—H32 | 121.1 |
O2—C10—H10 | 117.1 | N4—C2—N3 | 120.7 (2) |
O1—C10—H10 | 117.1 | N4—C2—N1 | 122.5 (2) |
N2—C1—N1 | 112.09 (18) | N3—C2—N1 | 116.85 (19) |
N2—C1—S1 | 122.24 (17) | C1—N2—H21 | 118.9 |
N1—C1—S1 | 125.67 (16) | C1—N2—H22 | 123.0 |
C2—N1—C1 | 130.95 (18) | H21—N2—H22 | 117.7 |
C2—N1—H1 | 113.1 | C2—N4—H41 | 113.6 |
C1—N1—H1 | 115.8 | C2—N4—H42 | 117.4 |
C2—N3—H31 | 119.9 | H41—N4—H42 | 128.8 |
C2—N3—H32 | 119.0 | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.87 | 1.87 | 2.708 (2) | 162 |
N3—H31···O2ii | 0.87 | 2.04 | 2.838 (2) | 152 |
N3—H32···O2 | 0.87 | 1.98 | 2.844 (3) | 176 |
N2—H21···O1i | 0.87 | 2.14 | 2.918 (2) | 148 |
N4—H42···O1 | 0.87 | 1.94 | 2.808 (3) | 172 |
N4—H41···S1 | 0.87 | 2.29 | 3.039 (2) | 144 |
N2—H22···S1iii | 0.87 | 2.55 | 3.409 (2) | 168 |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x+1, y+1/2, −z+3/2; (iii) −x+2, −y+3, −z+2. |
(II) bis[1-(diaminomethylene)thiouron-1-ium] oxalate dihydrate
top
Crystal data top
2C2H7N4S+·C2O42−·2H2O | Z = 1 |
Mr = 362.40 | F(000) = 190 |
Triclinic, P1 | Dx = 1.636 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.006 (3) Å | Cell parameters from 3612 reflections |
b = 7.221 (3) Å | θ = 3.0–36.9° |
c = 7.837 (3) Å | µ = 0.41 mm−1 |
α = 111.89 (3)° | T = 100 K |
β = 90.82 (3)° | Polyhedron, colourless |
γ = 91.02 (3)° | 0.24 × 0.21 × 0.13 mm |
V = 367.7 (3) Å3 | |
Data collection top
Kuma KM4 CCD area-detector diffractometer | 2114 independent reflections |
Radiation source: fine-focus sealed tube | 1827 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.010 |
ω scans | θmax = 36.9°, θmin = 3.0° |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | h = −11→8 |
Tmin = 0.909, Tmax = 0.952 | k = −9→9 |
4151 measured reflections | l = −10→10 |
Refinement top
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)] = 0.027 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.077 | All H-atom parameters refined |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0552P)2 + 0.0457P] where P = (Fo2 + 2Fc2)/3 |
2114 reflections | (Δ/σ)max = 0.001 |
136 parameters | Δρmax = 0.44 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
Crystal data top
2C2H7N4S+·C2O42−·2H2O | γ = 91.02 (3)° |
Mr = 362.40 | V = 367.7 (3) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.006 (3) Å | Mo Kα radiation |
b = 7.221 (3) Å | µ = 0.41 mm−1 |
c = 7.837 (3) Å | T = 100 K |
α = 111.89 (3)° | 0.24 × 0.21 × 0.13 mm |
β = 90.82 (3)° | |
Data collection top
Kuma KM4 CCD area-detector diffractometer | 2114 independent reflections |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | 1827 reflections with I > 2σ(I) |
Tmin = 0.909, Tmax = 0.952 | Rint = 0.010 |
4151 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.077 | All H-atom parameters refined |
S = 1.00 | Δρmax = 0.44 e Å−3 |
2114 reflections | Δρmin = −0.25 e Å−3 |
136 parameters | |
Special details top
Experimental. IR spectrum was collected on a Bruker spectrometer for a sample prepared as KBr
pellet. (II): 437.4 (w), 612.2 (m), 739.5 (m), 1000.3 (vw),
1113.6 (w), 1151.1 (w), 1290.9 (s), 1349.0 (m), 1506.3
(m), 1609.1 (vs), 1705.2 (vs), 3164.6 (s),
3414.0 (vs) |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C10 | 0.56225 (13) | 0.44763 (15) | 0.55224 (14) | 0.0102 (2) | |
O1 | 0.71513 (10) | 0.37060 (11) | 0.47447 (11) | 0.01222 (16) | |
O2 | 0.50434 (11) | 0.44719 (12) | 0.70129 (11) | 0.01379 (17) | |
S1 | 0.75312 (4) | −0.08046 (4) | −0.26075 (4) | 0.01355 (9) | |
N1 | 0.72837 (12) | 0.08000 (14) | 0.11236 (13) | 0.01075 (18) | |
H1 | 0.703 (2) | 0.180 (2) | 0.205 (2) | 0.015 (3)* | |
N2 | 0.64192 (13) | 0.27517 (15) | −0.04141 (14) | 0.01331 (19) | |
H21 | 0.616 (2) | 0.347 (2) | 0.055 (2) | 0.013 (3)* | |
H22 | 0.622 (2) | 0.302 (3) | −0.145 (3) | 0.034 (5)* | |
C1 | 0.70619 (13) | 0.09845 (16) | −0.05663 (15) | 0.0108 (2) | |
C2 | 0.78428 (13) | −0.07949 (15) | 0.15482 (14) | 0.0108 (2) | |
N3 | 0.77517 (14) | −0.05506 (15) | 0.33008 (13) | 0.0139 (2) | |
H31 | 0.740 (2) | 0.057 (3) | 0.407 (2) | 0.019 (4)* | |
H32 | 0.817 (2) | −0.150 (3) | 0.361 (2) | 0.033 (5)* | |
N4 | 0.84268 (13) | −0.24755 (15) | 0.03189 (14) | 0.01358 (19) | |
H41 | 0.8466 (19) | −0.266 (2) | −0.075 (2) | 0.011 (3)* | |
H42 | 0.878 (2) | −0.333 (2) | 0.073 (2) | 0.018 (4)* | |
O1W | 0.95343 (11) | 0.57493 (13) | 0.30177 (12) | 0.01514 (18) | |
H1W | 0.882 (2) | 0.524 (3) | 0.348 (2) | 0.032 (5)* | |
H2W | 1.055 (2) | 0.592 (2) | 0.362 (2) | 0.022 (4)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C10 | 0.0116 (4) | 0.0088 (4) | 0.0100 (5) | −0.0006 (3) | −0.0014 (3) | 0.0034 (4) |
O1 | 0.0118 (3) | 0.0124 (4) | 0.0124 (4) | 0.0024 (3) | 0.0007 (3) | 0.0044 (3) |
O2 | 0.0175 (3) | 0.0150 (4) | 0.0103 (4) | 0.0033 (3) | 0.0022 (3) | 0.0061 (3) |
S1 | 0.01694 (13) | 0.01423 (15) | 0.00827 (15) | 0.00054 (9) | 0.00136 (9) | 0.00274 (11) |
N1 | 0.0146 (4) | 0.0095 (4) | 0.0079 (4) | 0.0020 (3) | 0.0015 (3) | 0.0028 (4) |
N2 | 0.0177 (4) | 0.0132 (5) | 0.0089 (5) | 0.0029 (3) | 0.0012 (3) | 0.0039 (4) |
C1 | 0.0091 (4) | 0.0136 (5) | 0.0101 (5) | −0.0014 (3) | −0.0003 (3) | 0.0050 (4) |
C2 | 0.0096 (4) | 0.0114 (5) | 0.0118 (5) | 0.0001 (3) | 0.0003 (3) | 0.0050 (4) |
N3 | 0.0197 (4) | 0.0123 (5) | 0.0110 (5) | 0.0042 (3) | 0.0021 (3) | 0.0057 (4) |
N4 | 0.0175 (4) | 0.0119 (4) | 0.0114 (5) | 0.0028 (3) | 0.0005 (3) | 0.0042 (4) |
O1W | 0.0138 (3) | 0.0179 (4) | 0.0167 (4) | −0.0007 (3) | −0.0023 (3) | 0.0100 (3) |
Geometric parameters (Å, º) top
C10—O2 | 1.2431 (14) | N2—H22 | 0.907 (19) |
C10—O1 | 1.2709 (14) | C2—N4 | 1.3136 (16) |
C10—C10i | 1.571 (2) | C2—N3 | 1.3206 (15) |
S1—C1 | 1.6809 (14) | N3—H31 | 0.851 (17) |
N1—C2 | 1.3743 (15) | N3—H32 | 0.861 (19) |
N1—C1 | 1.3864 (15) | N4—H41 | 0.796 (15) |
N1—H1 | 0.834 (16) | N4—H42 | 0.835 (17) |
N2—C1 | 1.3243 (15) | O1W—H1W | 0.782 (19) |
N2—H21 | 0.769 (16) | O1W—H2W | 0.828 (16) |
| | | |
O2—C10—O1 | 126.00 (10) | N1—C1—S1 | 124.96 (9) |
O2—C10—C10i | 118.11 (11) | N4—C2—N3 | 120.87 (11) |
O1—C10—C10i | 115.90 (11) | N4—C2—N1 | 123.43 (10) |
C2—N1—C1 | 130.45 (10) | N3—C2—N1 | 115.69 (10) |
C2—N1—H1 | 113.2 (10) | C2—N3—H31 | 118.9 (11) |
C1—N1—H1 | 116.3 (10) | C2—N3—H32 | 117.0 (12) |
C1—N2—H21 | 117.2 (11) | H31—N3—H32 | 123.7 (16) |
C1—N2—H22 | 119.2 (12) | C2—N4—H41 | 122.4 (10) |
H21—N2—H22 | 123.4 (16) | C2—N4—H42 | 115.9 (11) |
N2—C1—N1 | 112.50 (10) | H41—N4—H42 | 121.7 (15) |
N2—C1—S1 | 122.55 (9) | H1W—O1W—H2W | 105.8 (16) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1 | 0.83 (2) | 2.05 (2) | 2.835 (2) | 157 (2) |
N2—H21···O2i | 0.77 (2) | 2.13 (2) | 2.888 (2) | 169 (2) |
N2—H22···O2ii | 0.91 (2) | 2.05 (2) | 2.897 (2) | 155 (2) |
N3—H31···O1 | 0.85 (2) | 2.14 (2) | 2.893 (2) | 148 (2) |
N3—H32···O1Wiii | 0.86 (2) | 2.11 (2) | 2.904 (2) | 152 (2) |
N4—H42···O1Wiii | 0.84 (2) | 2.20 (2) | 2.954 (2) | 151 (2) |
O1W—H1W···O1 | 0.78 (2) | 2.10 (2) | 2.874 (2) | 174 (2) |
O1W—H2W···O1iv | 0.83 (2) | 2.00 (2) | 2.821 (2) | 175 (2) |
N4—H41···S1 | 0.80 (2) | 2.41 (2) | 3.026 (2) | 135 (2) |
N3—H32···S1v | 0.86 (2) | 2.86 (2) | 3.285 (2) | 112 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y, z−1; (iii) x, y−1, z; (iv) −x+2, −y+1, −z+1; (v) x, y, z+1. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C2H7N4S+·CHO2− | 2C2H7N4S+·C2O42−·2H2O |
Mr | 164.19 | 362.40 |
Crystal system, space group | Monoclinic, P21/c | Triclinic, P1 |
Temperature (K) | 100 | 100 |
a, b, c (Å) | 12.693 (4), 5.509 (3), 11.576 (4) | 7.006 (3), 7.221 (3), 7.837 (3) |
α, β, γ (°) | 90, 115.80 (3), 90 | 111.89 (3), 90.82 (3), 91.02 (3) |
V (Å3) | 728.8 (5) | 367.7 (3) |
Z | 4 | 1 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.39 | 0.41 |
Crystal size (mm) | 0.19 × 0.14 × 0.04 | 0.24 × 0.21 × 0.13 |
|
Data collection |
Diffractometer | Kuma KM4 CCD area-detector diffractometer | Kuma KM4 CCD area-detector diffractometer |
Absorption correction | Analytical (CrysAlis RED; Oxford Diffraction, 2006) | Analytical (CrysAlis RED; Oxford Diffraction, 2006) |
Tmin, Tmax | 0.955, 0.981 | 0.909, 0.952 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6097, 1774, 1336 | 4151, 2114, 1827 |
Rint | 0.044 | 0.010 |
(sin θ/λ)max (Å−1) | 0.674 | 0.844 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.108, 1.00 | 0.027, 0.077, 1.00 |
No. of reflections | 1774 | 2114 |
No. of parameters | 99 | 136 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.28, −0.20 | 0.44, −0.25 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.87 | 1.87 | 2.708 (2) | 162 |
N3—H31···O2ii | 0.87 | 2.04 | 2.838 (2) | 152 |
N3—H32···O2 | 0.87 | 1.98 | 2.844 (3) | 176 |
N2—H21···O1i | 0.87 | 2.14 | 2.918 (2) | 148 |
N4—H42···O1 | 0.87 | 1.94 | 2.808 (3) | 172 |
N4—H41···S1 | 0.87 | 2.29 | 3.039 (2) | 144 |
N2—H22···S1iii | 0.87 | 2.55 | 3.409 (2) | 168 |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x+1, y+1/2, −z+3/2; (iii) −x+2, −y+3, −z+2. |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1 | 0.83 (2) | 2.05 (2) | 2.835 (2) | 157 (2) |
N2—H21···O2i | 0.77 (2) | 2.13 (2) | 2.888 (2) | 169 (2) |
N2—H22···O2ii | 0.91 (2) | 2.05 (2) | 2.897 (2) | 155 (2) |
N3—H31···O1 | 0.85 (2) | 2.14 (2) | 2.893 (2) | 148 (2) |
N3—H32···O1Wiii | 0.86 (2) | 2.11 (2) | 2.904 (2) | 152 (2) |
N4—H42···O1Wiii | 0.84 (2) | 2.20 (2) | 2.954 (2) | 151 (2) |
O1W—H1W···O1 | 0.78 (2) | 2.10 (2) | 2.874 (2) | 174 (2) |
O1W—H2W···O1iv | 0.83 (2) | 2.00 (2) | 2.821 (2) | 175 (2) |
N4—H41···S1 | 0.80 (2) | 2.41 (2) | 3.026 (2) | 135 (2) |
N3—H32···S1v | 0.86 (2) | 2.86 (2) | 3.285 (2) | 112 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y, z−1; (iii) x, y−1, z; (iv) −x+2, −y+1, −z+1; (v) x, y, z+1. |
Currently available data on HATU and its salts - dihedral
angles between the planes N1/C2/N3/N4 and N1/C1/N2/S1 (°) topCompound | Angle | Reference |
HATU at room temperature | 22.2 (1) | (a) |
HATU at 100 K | 19.4 (2) | (b) |
HATU, ab initio calculations | 6.2 | (c) |
[HATUH]+ nitrate | 7.2 (1) | (d) |
[HATUH]+ phosphonate monohydrate | 3.7 (1) | (d) |
[HATUH]+ chloride | 22.9 (1) | (c) |
[HATUH]+ bromide | 15.2 (1) | (c) |
[HATUH]+ iodide | 4.2 (1) | (c) |
[HATUH]+ chlorate(VII) | 1.4 (1) | (e) |
[HATUH]+ hydrogen sulfate | 9.8 (1) | (e) |
[HATUH]+ dihydrogen phosphate | 4.4 (1) | (e) |
[HATUH]+ dihydrogen arsenate | 2.1 (1) | (e) |
References:
(a) Janczak & Perpétuo (2008a);
(b) Hołyńska et al. (2009);
(c) Perpétuo & Janczak (2008);
(d) Janczak & Perpétuo (2009);
(e) Janczak & Perpétuo (2008b). |
1-(diaminomethylene)thiourea (HATU; Janczak & Perpétuo, 2008a; Hołyńska et al., 2009) and its oxidation products (Hołyńska & Kubiak, 2008) are already considered to be useful building blocks in crystal engineering. To explore the possibility of HATU forming predictable hydrogen-bonding patterns, it would be useful to observe its behaviour towards other known building blocks. Carboxylates and carboxylic acids (Steiner, 2001) are widely used in this context. In particular, aggregation patterns have been studied for carboxylates of amino acids (e.g. Prasad & Vijayan, 1993). Other examples in this line of research include the structures of inclusion compounds based on thiourea and carboxylic acids (Li & Mak, 1997). Supramolecular motifs have been successfully utilized in tuning the nonlinear properties of a series of N-(2-aminoethyl)-4-nitroaniline adducts with carboxylic acids (Jaya Prakash & Radhakrishnan, 2006). Molecular recognition of carboxylates by guanidinium cations has also been investigated in biological systems (Best et al., 2003). The crystal engineering of thioureas is still considered to be less developed than that of ureas (Custelcean, 2001).
The known crystal structures of 1-(diaminomethylene)thiouron-1-ium ([HATUH]+) salts include hydrogen halides (Perpétuo & Janczak, 2008), perchlorate, hydrogen sulfate, dihydrogen phosphate and dihydrogen arsenate (Janczak & Perpétuo, 2008b), as well as hydrogen difluoride and hexafluoridosilicate (Hołyńska & Kubiak, 2009). None of these is a salt of an organic acid. In this paper, the crystal structures of two representative [HATUH]+ carboxylates, the formate, (I), and the oxalate monohydrate, (II), are described and compared, with emphasis on the hydrogen-bonding motifs present.
Compounds (I) and (II) (Figs. 1 and 2) are the first structurally characterized organic [HATUH]+ carboxylates. Compound (I) is the formate, whereas (II) is the oxalate, with the anion sitting astride a symmetry centre. These anions were chosen as being the simplest examples of mono- and dicarboxylate anions, and were expected to participate in different supramolecular motifs in the crystal structures. The results reported herein ratify these expectations. In contrast, however, the acetate salt, homologous with the formate salt, is also isomorphous with the latter (see Experimental section), which underlines the role of the carboxylate group in motif formation in the crystal. Also, (II), in contrast with (I), incorporates water in the crystal structure, which further influences the hydrogen-bonding network.
The [HATUH]+ cation in both (I) and (II) is twisted, as previously observed for other salts of this cation (e.g. Janczak & Perpétuo, 2009a). The dihedral angles between the planes N1/C2/N3/N4 and N1/C1/N2/S1 are 5.5 (2)° for (I) and 4.5 (2)° for (II). These values are close to those calculated for the most stable conformation of [HATUH]+ by ab initio molecular orbital calculations (Table 1). The currently available data on [HATUH]+ salts show that the cation twisting may differ when different anions are used and is dependent on hydrogen bonding (Table 1). For the 1-(diaminomethylene)uron-1-ium cation in its hydrogen sulfate salt (Hołyńska & Kubiak, 2008) the analogous value is 1.8 (2)°.
The geometric parameters of the formate and oxalate anions in (I) and (II), respectively, do not deviate significantly from the reported values (e.g. melaminium formate; Perpétuo et al., 2005). The oxalate anion, as in most of the available structures [e.g. bis(N,N'-diphenylguanidinium) oxalate; Paixão et al., 1999], is flat and centrosymmetric. However, there are also cases of twisted oxalate anions, e.g. in 4-ammonio-1-methylpiperazin-1-ium oxalate dihydrate (Guo, 2004) or in (S,S)-N,N'-bis(2-hydroxy-2-butyl)ethylenediammonium oxalate pentahydrate (Bai et al., 2006).
The hydrogen-bonding patterns involving the carboxylate groups are different in (I) and (II). For (I), an R22(8) motif (Etter et al., 1990) is formed by donation to the formate anion from the amino groups bonded to atom C2 (N3—H32···O2 and N4—H42···O1; Figs. 1 and 3 and Table 2). In (II), these amino groups do not participate in a similar motif; rather, they are donors in an R21(6) pattern [N3—H32···O1Wiii and N4—H42···O1Wiii; symmetry code (iii) as in Table 3]. However, a similar motif to R22(8) in (I) is the R22(9) motif in (II), created via participation of the central atom N1 and the N2 amino group of the cation as donors, and atoms O1 and O2i [symmetry code: (i) 1 - x, 1 - y, 1 - z] from two different carboxyl groups of the centrosymmetric oxalate anion as acceptors (Figs. 2 and 4 and Table 3). It is interesting that the R21(6) motif present in (I) (Figs. 1 and 3), involving two hydrogen bonds with the central atom N1 and the N3 amino group of the cation as donors and a carboxylate O atom of the anion as acceptor, is robust enough to be retained in (II) (Fig. 4). This motif is also present in 1-(diaminomethylene)uron-1-ium hydrogen sulfate (Hołyńska & Kubiak, 2008).
A further structure-building principle is different in (I) and (II). Whereas in (I) subunits consisting of two formate anions and two [HATUH]+ cations, forming extended R44(16) motifs, can be distinguished (Fig. 3), in (II) a layered arrangement is present (Fig. 4). The hydrogen-bonded layers in (II) are connected via O—H···O hydrogen bonds (with a water molecule as donor and an oxalate anion as acceptor), which leads to the formation of R42(8) motifs consisting of two water molecules and two oxalate anions belonging to neighbouring layers. The presence of these specific contacts is possible since the plane of the oxalate anion interacting via the [HATUH]+ cation to form an R22(9) motif is inclined with respect to this cation [dihedral angles to the two cation `arms' are 40.8 (1) and 42.6 (1)° for N1/C2/N3/N4 and N1/C1/N2/S1, respectively]. On the other hand, in (I) the formate anion plane is also somewhat inclined to the planes of the `arms' of the interacting cation to form an R22(8) motif [dihedral angles 13.9 (2) and 9.3 (2)° to N1/C2/N3/N4 and N1/C1/N2/S1, respectively].
Recently, Janczak & Perpétuo (2009) reported a new type of interaction in [HATUH]+ salts, claimed to be a π–π stacking of parallel [HATUH]+ cations separated by about 3.27 Å. These interactions are said to stabilize the charge delocalization over the cation and significantly increase its planarity. In (II), the cations stack in an antiparallel fashion parallel to [100]. The N1/C1/N2/S1 arm of the molecule at (2 - x, -y, -z) eclipses the N1/C2/N3/N4 fragment of the molecule at (x, y, z), with a dihedral angle of 4.5 (2)° and with the distances of the atoms of one fragment from the plane of the other lying within the range 3.18 (1)–3.39 (1) Å. The molecule at (x, y, z) also interacts with the molecule at (1 - x, -y, -z) [the relevant distances as defined above are in the range 3.08 (1)–3.35 (1) Å]. In (I), on the other hand, the cations are arranged in chains rather than stacks, extending along [010]. Although the extent of the postulated cation π–π interactions differs greatly between (I) and (II), the twisting of the cations in these structures is not much affected by this difference.
The presence of S in the [HATUH]+ cation in (I) and (II) raises the question of whether there are hydrogen bonds with S as acceptor, although the importance of such interactions has been questioned (Allen et al., 1997b). Nevertheless, there are authors motivated by the high S content in biological systems, who claim to utilize weak D—H···S (D = donor) interactions in crystal engineering. For example, Valdez-Martinez et al. (2004) claim to have successfully designed a strategy of constructing thiourea derivatives so as to avoid the formation of intramolecular hydrogen bonds. Such intramolecular N—H···S hydrogen bonds seem to be present in the [HATUH]+ cation in (I) and (II) (Tables 2 and 3), as well as in other reported [HATUH]+ salts (e.g. Janczak & Perpétuo, 2009). Their formation is favoured based on considerations put forward by Etter et al. (1990) for six-membered hydrogen-bonded rings; the presence of the C═S bond makes it possible for some resonance-assisted stabilization to occur. Also, Allen et al. (1997a) discuss the possibility of resonance-induced hydrogen-bond formation with the S atom of a C═S group with N substituents. In (I) and (II), additional weak N—H···S interactions seem to occur. However, in both cases the `hydrogen bonds' involving S seem to be driven by the stronger hydrogen bonds present (Tables 2 and 3).
This study confirms the usefulness of HATU as a building block in crystal engineering and demonstrates its interaction with carboxylate, another common building block. Further insight into this field might be gained through examination of HATU-derivative carboxylate salts. We hope that the data for the simplest carboxylate and dicarboxylate [HATUH]+ salts will be useful in the design and description of new organic materials based on HATU ligand derivatives, which are worth investigating due to their potentially interesting properties and structures. The results of this study imply that the R21(6) graph-set motif (Etter et al., 1990) may be of importance in these investigations, but further conclusions await the analysis of different carboxylates.