Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805029004/wk6059sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536805029004/wk6059Isup2.hkl |
CCDC reference: 287741
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (C-C) = 0.005 Å
- R factor = 0.055
- wR factor = 0.123
- Data-to-parameter ratio = 13.1
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C7 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C8 PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.08 PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.14 PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 5 PLAT431_ALERT_2_C Short Inter HL..A Contact Cl2 .. O1 .. 3.15 Ang. PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd. # 2 C2 Cl3 O2
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 7 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 5 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion
2,2'-Biimidazole (2 mmol, 0.28 g) was suspended in water (30 ml). To the resulting suspension, concentrated aqueous trichloroacetic acid was added until the suspension became clear. The resulting solution was filtered and allowed to evaporate slowly at room temperature. After three weeks, colourless crystals of (I) appeared.
The H atoms of all N atoms were located from difference density maps and refined, with N—H distances restrained to 0.85 (2) Å, and with Uiso(H) = 1.2Ueq(N). The other H atoms were positioned geometrically and allowed to ride on their parent atoms at distances of Csp2—H = 0.93 Å and with Uiso(H) = 1.2Ueq(parent atom).
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97.
C6H7N4+·C2Cl3O2− | F(000) = 600 |
Mr = 297.53 | Dx = 1.679 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1438 reflections |
a = 12.4010 (13) Å | θ = 2.6–24.2° |
b = 5.5664 (6) Å | µ = 0.77 mm−1 |
c = 17.3648 (18) Å | T = 298 K |
β = 100.858 (2)° | Block, colourless |
V = 1177.2 (2) Å3 | 0.31 × 0.13 × 0.12 mm |
Z = 4 |
Bruker APEX area-detector diffractometer | 2129 independent reflections |
Radiation source: fine-focus sealed tube | 1812 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
ϕ and ω scans | θmax = 25.3°, θmin = 1.7° |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −14→14 |
Tmin = 0.796, Tmax = 0.913 | k = −6→6 |
5901 measured reflections | l = −20→15 |
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)] = 0.055 | Hydrogen site location: geom for CH and difmap for NH |
wR(F2) = 0.124 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.14 | w = 1/[σ2(Fo2) + (0.0437P)2 + 0.9103P] where P = (Fo2 + 2Fc2)/3 |
2129 reflections | (Δ/σ)max < 0.001 |
163 parameters | Δρmax = 0.31 e Å−3 |
3 restraints | Δρmin = −0.28 e Å−3 |
C6H7N4+·C2Cl3O2− | V = 1177.2 (2) Å3 |
Mr = 297.53 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.4010 (13) Å | µ = 0.77 mm−1 |
b = 5.5664 (6) Å | T = 298 K |
c = 17.3648 (18) Å | 0.31 × 0.13 × 0.12 mm |
β = 100.858 (2)° |
Bruker APEX area-detector diffractometer | 2129 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | 1812 reflections with I > 2σ(I) |
Tmin = 0.796, Tmax = 0.913 | Rint = 0.031 |
5901 measured reflections |
R[F2 > 2σ(F2)] = 0.055 | 3 restraints |
wR(F2) = 0.124 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.14 | Δρmax = 0.31 e Å−3 |
2129 reflections | Δρmin = −0.28 e Å−3 |
163 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.71002 (8) | −0.82356 (16) | 0.70084 (6) | 0.0519 (3) | |
Cl2 | 0.52275 (7) | −0.67802 (19) | 0.58778 (6) | 0.0582 (3) | |
Cl3 | 0.58366 (9) | −0.41198 (19) | 0.73127 (6) | 0.0643 (3) | |
O1 | 0.6633 (2) | −0.2887 (5) | 0.56260 (15) | 0.0603 (8) | |
O2 | 0.8033 (2) | −0.3819 (5) | 0.65586 (18) | 0.0690 (9) | |
N1 | 0.9417 (2) | −0.0367 (5) | 0.62658 (17) | 0.0408 (7) | |
N2 | 1.0299 (2) | 0.2672 (6) | 0.58630 (16) | 0.0448 (7) | |
N3 | 0.8404 (2) | 0.3665 (5) | 0.46057 (16) | 0.0421 (7) | |
N4 | 0.7490 (2) | 0.0753 (6) | 0.49863 (16) | 0.0411 (7) | |
C1 | 1.0397 (3) | −0.0192 (7) | 0.6768 (2) | 0.0511 (10) | |
H1 | 1.0650 | −0.1164 | 0.7200 | 0.061* | |
C2 | 1.0926 (3) | 0.1663 (7) | 0.6515 (2) | 0.0539 (10) | |
H2 | 1.1622 | 0.2190 | 0.6751 | 0.065* | |
C3 | 0.9382 (3) | 0.1388 (6) | 0.57350 (18) | 0.0341 (7) | |
C4 | 0.8453 (3) | 0.1900 (6) | 0.51222 (18) | 0.0342 (7) | |
C5 | 0.6821 (3) | 0.1835 (7) | 0.4371 (2) | 0.0491 (10) | |
H5 | 0.6105 | 0.1391 | 0.4156 | 0.059* | |
C6 | 0.7382 (3) | 0.3641 (7) | 0.4135 (2) | 0.0485 (9) | |
H6 | 0.7127 | 0.4697 | 0.3726 | 0.058* | |
C7 | 0.6342 (3) | −0.5741 (6) | 0.65736 (19) | 0.0367 (8) | |
C8 | 0.7085 (3) | −0.3986 (6) | 0.62063 (19) | 0.0360 (8) | |
H1A | 0.894 (2) | −0.140 (5) | 0.632 (2) | 0.043* | |
H3A | 0.889 (2) | 0.469 (5) | 0.455 (2) | 0.043* | |
H4A | 0.729 (3) | −0.038 (5) | 0.5259 (18) | 0.043* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0594 (6) | 0.0357 (5) | 0.0580 (6) | 0.0003 (4) | 0.0043 (4) | 0.0115 (4) |
Cl2 | 0.0425 (5) | 0.0595 (6) | 0.0664 (6) | −0.0212 (5) | −0.0058 (4) | 0.0084 (5) |
Cl3 | 0.0770 (7) | 0.0506 (6) | 0.0775 (7) | −0.0055 (5) | 0.0456 (6) | −0.0090 (5) |
O1 | 0.0639 (17) | 0.0609 (18) | 0.0489 (15) | −0.0302 (14) | −0.0077 (13) | 0.0206 (14) |
O2 | 0.0375 (15) | 0.071 (2) | 0.092 (2) | −0.0179 (14) | −0.0051 (14) | 0.0387 (17) |
N1 | 0.0302 (15) | 0.0423 (18) | 0.0496 (17) | −0.0074 (13) | 0.0071 (13) | 0.0115 (14) |
N2 | 0.0359 (16) | 0.0509 (18) | 0.0461 (17) | −0.0130 (14) | 0.0043 (13) | 0.0074 (14) |
N3 | 0.0384 (16) | 0.0480 (18) | 0.0393 (15) | −0.0131 (14) | 0.0057 (13) | 0.0082 (14) |
N4 | 0.0393 (16) | 0.0452 (18) | 0.0380 (16) | −0.0130 (14) | 0.0055 (12) | 0.0092 (13) |
C1 | 0.0367 (19) | 0.059 (2) | 0.053 (2) | −0.0033 (18) | −0.0018 (16) | 0.0180 (19) |
C2 | 0.0353 (19) | 0.065 (3) | 0.056 (2) | −0.0135 (19) | −0.0055 (16) | 0.012 (2) |
C3 | 0.0323 (17) | 0.0365 (18) | 0.0351 (17) | −0.0072 (14) | 0.0103 (13) | 0.0009 (14) |
C4 | 0.0337 (17) | 0.0375 (19) | 0.0328 (17) | −0.0107 (14) | 0.0096 (13) | −0.0002 (14) |
C5 | 0.040 (2) | 0.059 (2) | 0.044 (2) | −0.0156 (18) | −0.0019 (16) | 0.0093 (18) |
C6 | 0.044 (2) | 0.058 (2) | 0.0397 (19) | −0.0085 (18) | −0.0025 (16) | 0.0120 (18) |
C7 | 0.0377 (18) | 0.0309 (17) | 0.0409 (18) | −0.0060 (14) | 0.0056 (14) | 0.0013 (14) |
C8 | 0.0390 (19) | 0.0292 (17) | 0.0393 (18) | −0.0069 (14) | 0.0064 (15) | 0.0018 (15) |
Cl1—C7 | 1.765 (3) | N3—H3A | 0.843 (18) |
Cl2—C7 | 1.754 (3) | N4—C4 | 1.335 (4) |
Cl3—C7 | 1.777 (3) | N4—C5 | 1.363 (4) |
O1—C8 | 1.221 (4) | N4—H4A | 0.854 (18) |
O2—C8 | 1.222 (4) | C1—C2 | 1.341 (5) |
N1—C3 | 1.338 (4) | C1—H1 | 0.9300 |
N1—C1 | 1.359 (4) | C2—H2 | 0.9300 |
N1—H1A | 0.845 (18) | C3—C4 | 1.443 (4) |
N2—C3 | 1.325 (4) | C5—C6 | 1.330 (5) |
N2—C2 | 1.368 (4) | C5—H5 | 0.9300 |
N3—C4 | 1.324 (4) | C6—H6 | 0.9300 |
N3—C6 | 1.373 (4) | C7—C8 | 1.559 (4) |
C3—N1—C1 | 107.4 (3) | N3—C4—N4 | 108.1 (3) |
C3—N1—H1A | 130 (2) | N3—C4—C3 | 125.1 (3) |
C1—N1—H1A | 122 (2) | N4—C4—C3 | 126.8 (3) |
C3—N2—C2 | 104.7 (3) | C6—C5—N4 | 107.4 (3) |
C4—N3—C6 | 108.3 (3) | C6—C5—H5 | 126.3 |
C4—N3—H3A | 129 (2) | N4—C5—H5 | 126.3 |
C6—N3—H3A | 123 (2) | C5—C6—N3 | 107.6 (3) |
C4—N4—C5 | 108.6 (3) | C5—C6—H6 | 126.2 |
C4—N4—H4A | 127 (2) | N3—C6—H6 | 126.2 |
C5—N4—H4A | 124 (2) | C8—C7—Cl2 | 112.0 (2) |
C2—C1—N1 | 106.2 (3) | C8—C7—Cl1 | 111.1 (2) |
C2—C1—H1 | 126.9 | Cl2—C7—Cl1 | 108.81 (17) |
N1—C1—H1 | 126.9 | C8—C7—Cl3 | 107.1 (2) |
C1—C2—N2 | 110.5 (3) | Cl2—C7—Cl3 | 109.00 (18) |
C1—C2—H2 | 124.8 | Cl1—C7—Cl3 | 108.82 (17) |
N2—C2—H2 | 124.8 | O1—C8—O2 | 128.6 (3) |
N2—C3—N1 | 111.3 (3) | O1—C8—C7 | 115.9 (3) |
N2—C3—C4 | 123.9 (3) | O2—C8—C7 | 115.4 (3) |
N1—C3—C4 | 124.7 (3) | ||
C3—N1—C1—C2 | −0.6 (4) | N1—C3—C4—N3 | 178.5 (3) |
N1—C1—C2—N2 | 0.1 (5) | N2—C3—C4—N4 | −176.6 (3) |
C3—N2—C2—C1 | 0.4 (5) | N1—C3—C4—N4 | 0.5 (6) |
C2—N2—C3—N1 | −0.7 (4) | C4—N4—C5—C6 | 0.0 (4) |
C2—N2—C3—C4 | 176.7 (3) | N4—C5—C6—N3 | 0.3 (5) |
C1—N1—C3—N2 | 0.8 (4) | C4—N3—C6—C5 | −0.5 (4) |
C1—N1—C3—C4 | −176.5 (3) | Cl2—C7—C8—O1 | 26.5 (4) |
C6—N3—C4—N4 | 0.4 (4) | Cl1—C7—C8—O1 | 148.4 (3) |
C6—N3—C4—C3 | −177.9 (3) | Cl3—C7—C8—O1 | −92.9 (3) |
C5—N4—C4—N3 | −0.3 (4) | Cl2—C7—C8—O2 | −156.5 (3) |
C5—N4—C4—C3 | 178.0 (3) | Cl1—C7—C8—O2 | −34.6 (4) |
N2—C3—C4—N3 | 1.4 (5) | Cl3—C7—C8—O2 | 84.1 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O2 | 0.85 (2) | 1.85 (2) | 2.688 (4) | 172 (3) |
N3—H3A···N2i | 0.84 (2) | 2.00 (2) | 2.811 (4) | 163 (3) |
N4—H4A···O1 | 0.85 (2) | 1.79 (2) | 2.630 (4) | 167 (3) |
Symmetry code: (i) −x+2, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C6H7N4+·C2Cl3O2− |
Mr | 297.53 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 12.4010 (13), 5.5664 (6), 17.3648 (18) |
β (°) | 100.858 (2) |
V (Å3) | 1177.2 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.77 |
Crystal size (mm) | 0.31 × 0.13 × 0.12 |
Data collection | |
Diffractometer | Bruker APEX area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2002) |
Tmin, Tmax | 0.796, 0.913 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5901, 2129, 1812 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.600 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.124, 1.14 |
No. of reflections | 2129 |
No. of parameters | 163 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.31, −0.28 |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2002), SHELXL97.
O1—C8 | 1.221 (4) | N3—C6 | 1.373 (4) |
O2—C8 | 1.222 (4) | N4—C4 | 1.335 (4) |
N1—C3 | 1.338 (4) | N4—C5 | 1.363 (4) |
N1—C1 | 1.359 (4) | C1—C2 | 1.341 (5) |
N2—C3 | 1.325 (4) | C3—C4 | 1.443 (4) |
N2—C2 | 1.368 (4) | C5—C6 | 1.330 (5) |
N3—C4 | 1.324 (4) | C7—C8 | 1.559 (4) |
C3—N1—C1 | 107.4 (3) | N3—C4—N4 | 108.1 (3) |
C3—N2—C2 | 104.7 (3) | N3—C4—C3 | 125.1 (3) |
C4—N3—C6 | 108.3 (3) | N4—C4—C3 | 126.8 (3) |
C4—N4—C5 | 108.6 (3) | C6—C5—N4 | 107.4 (3) |
C2—C1—N1 | 106.2 (3) | C5—C6—N3 | 107.6 (3) |
C1—C2—N2 | 110.5 (3) | O1—C8—O2 | 128.6 (3) |
N2—C3—N1 | 111.3 (3) | O1—C8—C7 | 115.9 (3) |
N2—C3—C4 | 123.9 (3) | O2—C8—C7 | 115.4 (3) |
N1—C3—C4 | 124.7 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O2 | 0.845 (18) | 1.848 (19) | 2.688 (4) | 172 (3) |
N3—H3A···N2i | 0.843 (18) | 2.00 (2) | 2.811 (4) | 163 (3) |
N4—H4A···O1 | 0.854 (18) | 1.79 (2) | 2.630 (4) | 167 (3) |
Symmetry code: (i) −x+2, −y+1, −z+1. |
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2,2'-Biimidazole, H2biim, is not only a proton donor, but also a proton acceptor, so that it possesses five possible forms, i.e. di-deprotonated (dianion, biim2−), mono-deprotonated (monoanion, Hbiim−), neutral (neutral, H2biim), mono-protonated (monocation, H3biim+) and di-protonated (dication, H4biim2+). Therefore, H2biim is a excellent candidate for the development of supramolecular motifs in crystals, and homomeric hydrogen-bonded motifs R22(10) (Cromer et al., 1987), heteromeric hydrogen-bonded motifs R22(9) (Ye et al., 2005) and R21(7) (Belanger & Beauchamp, 1996), and mixed hydrogen-bonded motifs R22(10) and R21(7) (Ramirez et al., 2002), have been structurally reported. In order to extend this research, the crystal structure of the title compound, C6H7N4+.C2Cl3O2−, (I), is reported here.
The bond distances and angles of the mono-protonated H3biim+ in (I) are unexceptional and compare well with the values in neutral H2biim (Cromer et al., 1987) (Table 1 and Fig. 1). The two rings are almost coplanar in both cases. The dihedral angle between the two five-membered rings in neutral H2biim is 4.6°, and is slightly smaller in (I) at 4.47 (3)°.
Two N—H···O hydrogen bonds connect the H3biim+ cations and trichloroacetate anions to produce ion pairs, and two adjacent ion pairs are linked into a dimer by a third N3—H3A···N2i hydrogen bond [Table 2; symmetry code: (i) 2 − x, 1 − y, 1 − z]. The hydrogen-bonding pattern, as shown in Fig. 2, can be described in graph-set motifs (Etter, 1990; Grell et al., 2000) as R22(9) and R22(10). Adjacent dimers are associated by π–π interactions between the five-membered rings of the H3biim+ moieties [at (x, y, z) and (2 − x, −y, 1 − z)], with the ring centroids separated by 3.861 (1) Å, forming a ribbon-like supramolecular array along the b axis (Fig. 3).