Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110004221/sq3234sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270110004221/sq3234Isup2.hkl |
CCDC reference: 774899
All reagents and solvents employed were commercially available and used as supplied without further purification. For the preparation of (I), solid Cd(OH)2 (0.0365 g, 0.25 mmol), which is necessary for the crystallization of the product, was added to an ethanol–water (1:1 v/v) solution (5 ml) of H2tfbdc (0.0595 g, 0.25 mmol) and ImH (0.0170 g, 0.25 mmol). After stirring for 1 h, the reaction mixture was filtered and left to stand at ambient temperature. Colourless block-shaped crystals of (I), suitable for X-ray diffraction, were obtained after evaporation of the filtrate for one week [yield 67%, 0.0513 g (based on ImH)]. Analysis, calculated for C11H6F4N2O4: C 43.15, H 1.98, N 9.15%; found: C 43.17, H 1.20, N 9.13%. Spectroscopic analysis: IR (KBr pellet, ν, cm-1): 3169 (s), 2992 (w), 2856 (w), 1721 (w), 1626 (m), 1590 (m), 1474 (s), 1366 (m), 1307 (s), 1213 (m), 1178 (w), 1055 (m), 991 (s), 768 (m), 707(s), 631 (m), 508 (m), 488 (s).
All C-bound H atoms were positioned theoretically and treated as riding atoms, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C). N- and O-bound H atoms were initially located in difference maps, then geometrically optimized and refined as riding, with N—H = 0.86 Å and O—H = 0.82 Å, and with Uiso(H) = 1.2Ueq(N) or 1.5Ueq(O). Friedel pairs were collected but merged before the final refinement and the absolute configuration was chosen arbitrarily.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
C3H5N2+·C8F4HO4− | F(000) = 616 |
Mr = 306.18 | Dx = 1.664 Mg m−3 |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 3571 reflections |
a = 9.716 (3) Å | θ = 2.3–27.6° |
b = 7.229 (3) Å | µ = 0.17 mm−1 |
c = 17.406 (6) Å | T = 296 K |
V = 1222.5 (7) Å3 | Block, colourless |
Z = 4 | 0.30 × 0.30 × 0.20 mm |
Bruker SMART APEX CCD diffractometer | 1457 independent reflections |
Radiation source: fine-focus sealed tube | 1330 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
Detector resolution: 0 pixels mm-1 | θmax = 27.6°, θmin = 2.3° |
ϕ and ω scans | h = −12→12 |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | k = −9→9 |
Tmin = 0.952, Tmax = 0.968 | l = −22→22 |
9957 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.027 | H-atom parameters constrained |
wR(F2) = 0.074 | w = 1/[σ2(Fo2) + (0.0451P)2 + 0.0992P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
1457 reflections | Δρmax = 0.25 e Å−3 |
191 parameters | Δρmin = −0.16 e Å−3 |
1 restraint | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc* = kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.018 (2) |
C3H5N2+·C8F4HO4− | V = 1222.5 (7) Å3 |
Mr = 306.18 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 9.716 (3) Å | µ = 0.17 mm−1 |
b = 7.229 (3) Å | T = 296 K |
c = 17.406 (6) Å | 0.30 × 0.30 × 0.20 mm |
Bruker SMART APEX CCD diffractometer | 1457 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 1330 reflections with I > 2σ(I) |
Tmin = 0.952, Tmax = 0.968 | Rint = 0.029 |
9957 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 1 restraint |
wR(F2) = 0.074 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.25 e Å−3 |
1457 reflections | Δρmin = −0.16 e Å−3 |
191 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 | ||
F1 | 0.42776 (14) | 0.5920 (2) | −0.07757 (7) | 0.0454 (3) | |
F2 | 0.69164 (13) | 0.6496 (2) | −0.04859 (8) | 0.0462 (3) | |
F3 | 0.36969 (12) | 0.3520 (2) | 0.17285 (7) | 0.0455 (3) | |
F4 | 0.63344 (13) | 0.4084 (2) | 0.20130 (8) | 0.0468 (3) | |
O1 | 0.20150 (16) | 0.3642 (2) | −0.02812 (8) | 0.0410 (4) | |
O2 | 0.15456 (14) | 0.5081 (2) | 0.08150 (8) | 0.0377 (4) | |
O3 | 0.90284 (14) | 0.4847 (2) | 0.04279 (10) | 0.0407 (4) | |
H3 | 0.9832 | 0.4958 | 0.0564 | 0.061* | |
O4 | 0.85978 (15) | 0.6410 (3) | 0.15075 (9) | 0.0458 (4) | |
C1 | 0.38844 (19) | 0.4724 (3) | 0.04701 (12) | 0.0273 (4) | |
C2 | 0.4755 (2) | 0.5446 (3) | −0.00816 (11) | 0.0297 (4) | |
C3 | 0.6137 (2) | 0.5735 (3) | 0.00650 (12) | 0.0308 (4) | |
C4 | 0.6716 (2) | 0.5305 (3) | 0.07715 (12) | 0.0293 (4) | |
C5 | 0.5845 (2) | 0.4576 (3) | 0.13208 (12) | 0.0301 (4) | |
C6 | 0.4463 (2) | 0.4288 (3) | 0.11741 (12) | 0.0296 (4) | |
C7 | 0.23534 (19) | 0.4443 (3) | 0.03141 (11) | 0.0278 (4) | |
C8 | 0.8223 (2) | 0.5593 (3) | 0.09441 (12) | 0.0303 (4) | |
N1 | 0.1433 (2) | 0.5881 (3) | 0.24288 (12) | 0.0513 (5) | |
H1 | 0.1559 | 0.5844 | 0.1940 | 0.077* | |
N2 | 0.1630 (2) | 0.6764 (3) | 0.35864 (12) | 0.0453 (5) | |
H2 | 0.1944 | 0.7350 | 0.3979 | 0.068* | |
C9 | 0.2114 (3) | 0.6965 (4) | 0.28898 (14) | 0.0514 (6) | |
H9A | 0.2828 | 0.7751 | 0.2748 | 0.062* | |
C10 | 0.0465 (3) | 0.4950 (4) | 0.28392 (15) | 0.0527 (6) | |
H10A | −0.0160 | 0.4090 | 0.2649 | 0.063* | |
C11 | 0.0584 (3) | 0.5505 (4) | 0.35669 (15) | 0.0540 (7) | |
H11A | 0.0056 | 0.5110 | 0.3981 | 0.065* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F1 | 0.0323 (7) | 0.0729 (9) | 0.0310 (6) | −0.0017 (6) | −0.0050 (5) | 0.0119 (6) |
F2 | 0.0278 (6) | 0.0714 (9) | 0.0395 (7) | −0.0075 (6) | 0.0069 (5) | 0.0144 (7) |
F3 | 0.0275 (6) | 0.0703 (9) | 0.0386 (7) | −0.0063 (6) | 0.0045 (5) | 0.0152 (7) |
F4 | 0.0293 (7) | 0.0746 (9) | 0.0365 (7) | −0.0025 (6) | −0.0063 (5) | 0.0153 (7) |
O1 | 0.0272 (7) | 0.0602 (10) | 0.0357 (8) | 0.0000 (7) | −0.0019 (6) | −0.0145 (7) |
O2 | 0.0185 (6) | 0.0610 (9) | 0.0336 (7) | 0.0001 (6) | 0.0015 (6) | −0.0128 (7) |
O3 | 0.0171 (6) | 0.0628 (9) | 0.0422 (8) | −0.0002 (6) | −0.0007 (6) | −0.0144 (8) |
O4 | 0.0295 (8) | 0.0667 (11) | 0.0412 (9) | −0.0031 (7) | −0.0027 (7) | −0.0147 (8) |
C1 | 0.0189 (8) | 0.0325 (9) | 0.0304 (9) | 0.0017 (7) | 0.0013 (8) | −0.0036 (7) |
C2 | 0.0240 (10) | 0.0388 (10) | 0.0262 (9) | 0.0028 (8) | −0.0023 (8) | 0.0004 (7) |
C3 | 0.0224 (9) | 0.0372 (10) | 0.0328 (10) | −0.0005 (8) | 0.0046 (8) | 0.0029 (8) |
C4 | 0.0194 (8) | 0.0345 (9) | 0.0341 (10) | 0.0006 (7) | 0.0001 (8) | −0.0024 (8) |
C5 | 0.0221 (9) | 0.0390 (10) | 0.0293 (9) | 0.0020 (8) | −0.0005 (8) | 0.0015 (8) |
C6 | 0.0209 (9) | 0.0378 (10) | 0.0301 (9) | −0.0005 (8) | 0.0045 (7) | 0.0026 (8) |
C7 | 0.0176 (8) | 0.0363 (9) | 0.0296 (10) | 0.0004 (7) | −0.0001 (8) | −0.0009 (7) |
C8 | 0.0203 (9) | 0.0376 (9) | 0.0330 (10) | −0.0018 (7) | −0.0006 (8) | 0.0003 (8) |
N1 | 0.0480 (12) | 0.0780 (14) | 0.0279 (9) | 0.0091 (10) | −0.0018 (9) | −0.0079 (10) |
N2 | 0.0495 (11) | 0.0558 (11) | 0.0304 (8) | 0.0031 (9) | −0.0080 (8) | −0.0100 (8) |
C9 | 0.0479 (14) | 0.0661 (15) | 0.0403 (12) | −0.0060 (12) | −0.0003 (12) | 0.0038 (12) |
C10 | 0.0513 (15) | 0.0611 (14) | 0.0458 (13) | −0.0049 (13) | −0.0130 (13) | −0.0068 (12) |
C11 | 0.0472 (15) | 0.0775 (18) | 0.0371 (12) | −0.0058 (12) | 0.0018 (11) | 0.0066 (12) |
F1—C2 | 1.339 (2) | C4—C5 | 1.382 (3) |
F2—C3 | 1.340 (2) | C4—C8 | 1.509 (3) |
F3—C6 | 1.339 (2) | C5—C6 | 1.382 (3) |
F4—C5 | 1.343 (2) | N1—C9 | 1.302 (3) |
O1—C7 | 1.232 (2) | N1—C10 | 1.359 (4) |
O2—C7 | 1.261 (2) | N1—H1 | 0.8600 |
O3—C8 | 1.308 (3) | N2—C9 | 1.309 (3) |
O3—H3 | 0.8199 | N2—C11 | 1.364 (4) |
O4—C8 | 1.201 (3) | N2—H2 | 0.8600 |
C1—C2 | 1.382 (3) | C9—H9A | 0.9300 |
C1—C6 | 1.385 (3) | C10—C11 | 1.334 (4) |
C1—C7 | 1.526 (3) | C10—H10A | 0.9300 |
C2—C3 | 1.382 (3) | C11—H11A | 0.9300 |
C3—C4 | 1.388 (3) | ||
C8—O3—H3 | 109.4 | O1—C7—C1 | 118.19 (17) |
C2—C1—C6 | 116.88 (16) | O2—C7—C1 | 115.81 (18) |
C2—C1—C7 | 121.55 (18) | O4—C8—O3 | 125.59 (19) |
C6—C1—C7 | 121.57 (18) | O4—C8—C4 | 121.64 (19) |
F1—C2—C1 | 120.78 (17) | O3—C8—C4 | 112.77 (18) |
F1—C2—C3 | 117.67 (17) | C9—N1—C10 | 109.0 (2) |
C1—C2—C3 | 121.55 (18) | C9—N1—H1 | 123.8 |
F2—C3—C2 | 118.62 (18) | C10—N1—H1 | 127.1 |
F2—C3—C4 | 119.76 (18) | C9—N2—C11 | 108.6 (2) |
C2—C3—C4 | 121.59 (18) | C9—N2—H2 | 123.6 |
C5—C4—C3 | 116.73 (17) | C11—N2—H2 | 127.8 |
C5—C4—C8 | 120.63 (19) | N1—C9—N2 | 108.7 (3) |
C3—C4—C8 | 122.64 (18) | N1—C9—H9A | 125.6 |
F4—C5—C4 | 120.31 (17) | N2—C9—H9A | 125.6 |
F4—C5—C6 | 118.02 (18) | C11—C10—N1 | 106.9 (2) |
C4—C5—C6 | 121.65 (19) | C11—C10—H10A | 126.6 |
F3—C6—C5 | 117.99 (19) | N1—C10—H10A | 126.6 |
F3—C6—C1 | 120.39 (18) | C10—C11—N2 | 106.8 (2) |
C5—C6—C1 | 121.60 (19) | C10—C11—H11A | 126.6 |
O1—C7—O2 | 126.00 (18) | N2—C11—H11A | 126.6 |
C6—C1—C2—F1 | −179.39 (17) | C4—C5—C6—C1 | −0.3 (3) |
C7—C1—C2—F1 | −0.2 (3) | C2—C1—C6—F3 | −177.56 (18) |
C6—C1—C2—C3 | −0.6 (3) | C7—C1—C6—F3 | 3.2 (3) |
C7—C1—C2—C3 | 178.64 (18) | C2—C1—C6—C5 | 0.5 (3) |
F1—C2—C3—F2 | 1.0 (3) | C7—C1—C6—C5 | −178.70 (19) |
C1—C2—C3—F2 | −177.83 (17) | C2—C1—C7—O1 | 49.2 (3) |
F1—C2—C3—C4 | 179.23 (18) | C6—C1—C7—O1 | −131.6 (2) |
C1—C2—C3—C4 | 0.4 (3) | C2—C1—C7—O2 | −130.3 (2) |
F2—C3—C4—C5 | 178.10 (19) | C6—C1—C7—O2 | 48.9 (3) |
C2—C3—C4—C5 | −0.1 (3) | C5—C4—C8—O4 | −51.2 (3) |
F2—C3—C4—C8 | −2.3 (3) | C3—C4—C8—O4 | 129.2 (2) |
C2—C3—C4—C8 | 179.48 (19) | C5—C4—C8—O3 | 127.9 (2) |
C3—C4—C5—F4 | 178.45 (18) | C3—C4—C8—O3 | −51.6 (3) |
C8—C4—C5—F4 | −1.1 (3) | C10—N1—C9—N2 | 0.3 (3) |
C3—C4—C5—C6 | 0.0 (3) | C11—N2—C9—N1 | −0.5 (3) |
C8—C4—C5—C6 | −179.55 (19) | C9—N1—C10—C11 | −0.1 (3) |
F4—C5—C6—F3 | −0.6 (3) | N1—C10—C11—N2 | −0.2 (3) |
C4—C5—C6—F3 | 177.86 (18) | C9—N2—C11—C10 | 0.4 (3) |
F4—C5—C6—C1 | −178.71 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2 | 0.86 | 2.03 | 2.870 (3) | 164 |
N2—H2···O1i | 0.86 | 1.89 | 2.732 (3) | 168 |
O3—H3···O2ii | 0.82 | 1.72 | 2.5425 (19) | 177 |
C9—H9A···O4iii | 0.93 | 2.36 | 3.041 (3) | 130 |
C11—H11A···O1iv | 0.93 | 2.55 | 3.283 (3) | 136 |
Symmetry codes: (i) −x+1/2, y+1/2, z+1/2; (ii) x+1, y, z; (iii) x−1/2, −y+3/2, z; (iv) −x, −y+1, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C3H5N2+·C8F4HO4− |
Mr | 306.18 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 296 |
a, b, c (Å) | 9.716 (3), 7.229 (3), 17.406 (6) |
V (Å3) | 1222.5 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.17 |
Crystal size (mm) | 0.30 × 0.30 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.952, 0.968 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9957, 1457, 1330 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.651 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.074, 1.08 |
No. of reflections | 1457 |
No. of parameters | 191 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.16 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2 | 0.86 | 2.03 | 2.870 (3) | 163.7 |
N2—H2···O1i | 0.86 | 1.89 | 2.732 (3) | 167.8 |
O3—H3···O2ii | 0.82 | 1.72 | 2.5425 (19) | 176.6 |
C9—H9A···O4iii | 0.93 | 2.36 | 3.041 (3) | 129.5 |
C11—H11A···O1iv | 0.93 | 2.55 | 3.283 (3) | 135.8 |
Symmetry codes: (i) −x+1/2, y+1/2, z+1/2; (ii) x+1, y, z; (iii) x−1/2, −y+3/2, z; (iv) −x, −y+1, z+1/2. |
Hydrogen bonding has long been considered important in biological systems and molecular recognition (Philp & Stoddart, 1996). Nowadays, the application of intermolecular hydrogen bonds is a well known and efficient tool to design and synthesize supramolecular assemblies (Prior & Rosseinsky, 2000; Beatty, 2003; Bhogala et al., 2005). Classical hydrogen bonds (such as O—H···O, O—H···N etc.) have proven to be ideal tools to rationalize and systematize the relationship between molecular and supramolecular structures (Desiraju & Steiner, 1999; Steiner & Desiraju, 1998; Mascal et al., 2000). For example, many organic crystalline materials, composed of N-donor compounds such as ImH, benzimidazole, pyridine and 4,4'-bipyridinium, and aromatic multi-carboxylic acids such as 1,4-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid and 1,2,3,4,5,6-benzenehexacarboxylic acid, have been documented. Although coordination compounds synthesized with halogen-substituted aromatic multi-carboxylic acids have been reported (Wang et al., 2007; Roques et al., 2007; Liu et al., 2008; Sergio et al., 2008; Chen et al., 2008, 2006; Li et al., 2008; Eddaoudi et al., 2002), to the best of our knowledge studies of their supramolecular interactions have been less well explored (Luo & Palmore, 2002; Lan et al., 2008; He et al., 2009). Recently, we have obtained two complexes with 2,3,5,6-tetrafluoroterephthalic acid (H2tfbdc) under mild solution synthetic conditions (Zhu et al., 2008, 2009). To further the development of such interesting hydrogen-bonded supramolecular systems and as a continuation of our research in this area, we deliberately chose H2tfbdc to react with an excellent N-donor compound, imidazole (ImH), and isolated the the first organic crystalline product containing the Htfbdc- anion. The title salt, (I), was an unexpected product of an attempt to form an extended structure incorporating Cd2+ cations.
Compound (I) crystallizes in the orthorhombic space group Pna21. The asymmetric unit contains one Htfbdc- anion and one ImH2+ cation, linked by an N—H···O hydrogen bond between the protonated amine and the deprotonated carboxylate group (Fig. 1). Proton transfer from the H2tfbdc to the ImH was unequivocally established from difference map plots. The compound is thus shown to be an organic proton-transfer binary salt, in which the acidic H+ of one carboxyl group O atom is transferred to an imidazole N atom, while the other carboxyl group remains as the acid. The carboxylic acid and carboxylate groups are distinctly twisted away from the arene ring, with dihedral angles of 49.1 (1) and 51.5 (1)°, respectively, notably larger than the corresponding values in 4-methylimidazolium hydrogenterephthalate [5.7 (1) and 21.9 (1)°, respectively; Meng et al., 2008]. The plane of the aromatic ring of the Htfbdc- anion is inclined at 40.9 (1)° to that of the ImH2+ component, which is much smaller than the analogous angle in 4-methylimidazolium hydrogenterephthalate [60.6 (1)°; Meng et al., 2008]. These differences may be due to the influence of the steric hindrance of the adjacent fluoro substituents.
The carboxyl/carboxylate C—O bond lengths in (I) [C7—O1 = 1.233 (3), C7—O2 = 1.260 (2), C8—O3 = 1.307 (3) and C8—O4 = 1.201 (3) Å] agree well with those tabulated by Allen et al. (1995) for a carboxyl [1.305 (20) and 1.226 (20) Å] and/or a carboxylate group [1.255 (10) Å] attached to an arene ring. The bond distances and angles in the ImH2+ cation are also indicative of its protonation compared with analogous compounds.
In the extended structure of (I) (Fig. 2), linear tapes of Htfbdc- anions are generated along the a axis through O3—H3···O2ii hydrogen bonds [symmetry code: (ii) x + 1, y, z] (Table 1). The distance between the two carboxyl O atoms in the hydrogen bond is slightly shorter than those seen in other carboxylic acid compounds, such as terephthalic acid (2.620 Å; Domenicano et al., 1990) and bis(2,4'-bipyridin-1'-ium)2,5-dicarboxybenzene-1,4-carboxylate benzene-1,2,4,5-tetracarboxylic acid (2.607 Å; Cui et al., 2005), indicating the strength of the interactions in (I). The linear tapes are very similar to the one-dimensional chains formed by the hydrogenterephthalate anions in 4-methylimidazolium hydrogenterephthalate (Meng et al., 2008).
Adjacent anion chains are linked together by ImH2+ cations via N1—H1A···O2 and N2—H2A···O1i hydrogen bonds [symmetry code: (i) -x + 1/2, y + 1/2, z + 1/2], forming two-dimensional layers containing R56(32) hydrogen-bond motifs (Fig. 2) (for definition of graph-set notation, see Bernstein et al., 1995). The network thus formed is topologically equivalent to a (4,4) network (Batten & Robson, 1998). Each cavity is interwoven by another network in the so-called alternative [Alternating?] mode of inclined interpenetration, with an angle of interpenetration of 45.1° (Fig. 3), producing an interlocked three-dimensional structure.
The ImH2+ cations linked to opposite sides of the same Htfbdc- anion chain are almost perpendicular to each other [82.0 (1)°], while the dihedral angle between the Htfbdc- rings of different chains is 23.5 (1)°. This pattern is somewhat different from what is seen in the two-dimensional layers formed by similar strong O—H···O and N—H···O hydrogen bonds with an R46(32) ring pattern in 4-methylimidazolium hydrogenterephthalate (Meng et al., 2008), in which the Htfbdc- anions of adjacent chains are parallel to each other and all 4-methylimidazolium cations are oriented in the same direction, so that the resulting (4,4) network layers are also parallel to each other.
Compound (I) extends further to its final three-dimensional network through weak intermolecular C9—H9A···O4iii and C11—H11A···O1iv interactions (Table 1) [symmetry codes: (iii) x - 1/2, -y + 3/2, z; (iv) -x, -y + 1, z + 1/2]. The H···A lengths of these hydrogen bonds are in the range 2.30–2.60 Å, comparable with those found in protein complexes (Jiang & Lai, 2002).
This work demonstrates the first example of a fluorinated terephthalic acid as a good participant in organic salt formation with an N-donor compound. Compound (I) is linked by O—H···O and N—H···O hydrogen bonds into an interlocked three-dimensional structure in an alternative [Alternating?] mode of inclined interpenetration of (4,4) network layers. Additional studies are warranted to provide further insight into the potential of these molecules to form engineered structures in salts or co-crystals.