In the title complex, 2C
9H
10O
4·C
8H
12N
2, there is an inversion centre at the centre of the 2,3,5,6-tetramethylpyrazine molecule, which is linked to two
endo-norbornene-
cis-5,6-dicarboxylic acid molecules
via O—H
N hydrogen bonds. In the crystal structure, O—H
O and O—H
N hydrogen bonds propagate a one-dimensional zigzag chain, which is extended into layers when combined with longer C—H
O hydrogen bonds.
Supporting information
CCDC reference: 269848
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (C-C) = 0.008 Å
- R factor = 0.096
- wR factor = 0.326
- Data-to-parameter ratio = 12.9
checkCIF/PLATON results
No syntax errors found
Alert level C
RFACR01_ALERT_3_C The value of the weighted R factor is > 0.25
Weighted R factor given 0.326
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.97
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ?
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
PLAT084_ALERT_2_C High R2 Value .................................. 0.33
PLAT150_ALERT_1_C Volume as Calculated Differs from that Given ... 626.10 Ang-3
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 8
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd. # 2
C8 H12 N2
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
8 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
1 ALERT type 2 Indicator that the structure model may be wrong or deficient
3 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
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.
Tetramethylpyrazine–endo-norbornene-
cis-5,6-dicarboxylic acid (1/2)
top
Crystal data top
C9H10O4·0.5C8H12N2 | Z = 2 |
Mr = 250.27 | F(000) = 266 |
Triclinic, P1 | Dx = 1.327 Mg m−3 |
Hall symbol: -P1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.106 (2) Å | Cell parameters from 986 reflections |
b = 9.293 (3) Å | θ = 2.7–24.4° |
c = 11.580 (4) Å | µ = 0.10 mm−1 |
α = 101.875 (8)° | T = 298 K |
β = 97.890 (6)° | Block, colorless |
γ = 98.590 (8)° | 0.22 × 0.13 × 0.12 mm |
V = 626.1 (4) Å3 | |
Data collection top
Bruker APEX area-detector diffractometer | 2149 independent reflections |
Radiation source: fine-focus sealed tube | 1374 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.023 |
φ and ω scans | θmax = 25.0°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −6→7 |
Tmin = 0.979, Tmax = 0.988 | k = −11→9 |
3212 measured reflections | l = −13→11 |
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)] = 0.096 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.326 | H-atom parameters constrained |
S = 1.22 | w = 1/[σ2(Fo2) + (0.2P)2] where P = (Fo2 + 2Fc2)/3 |
2149 reflections | (Δ/σ)max < 0.001 |
167 parameters | Δρmax = 0.53 e Å−3 |
0 restraints | Δρmin = −0.45 e Å−3 |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.7089 (7) | 0.8995 (5) | 0.4539 (4) | 0.0539 (13) | |
H1 | 0.8045 | 0.9480 | 0.5108 | 0.081* | |
O2 | 0.9940 (7) | 0.9262 (5) | 0.3574 (4) | 0.0554 (12) | |
O3 | 0.9186 (7) | 0.5820 (5) | 0.3271 (4) | 0.0553 (13) | |
H3 | 1.0315 | 0.5501 | 0.3491 | 0.083* | |
O4 | 1.0845 (7) | 0.5991 (5) | 0.1714 (4) | 0.0601 (13) | |
N1 | 1.3035 (7) | 0.5209 (5) | 0.4383 (4) | 0.0409 (12) | |
C1 | 1.2874 (11) | 0.7434 (7) | 0.5853 (7) | 0.064 (2) | |
H1A | 1.3829 | 0.8360 | 0.5868 | 0.096* | |
H1B | 1.2590 | 0.7423 | 0.6647 | 0.096* | |
H1C | 1.1475 | 0.7340 | 0.5326 | 0.096* | |
C2 | 1.4009 (9) | 0.6153 (6) | 0.5414 (5) | 0.0380 (13) | |
C3 | 1.4009 (9) | 0.4064 (5) | 0.3933 (5) | 0.0368 (13) | |
C4 | 1.2833 (11) | 0.3014 (6) | 0.2791 (5) | 0.0525 (17) | |
H4A | 1.1758 | 0.3481 | 0.2387 | 0.079* | |
H4B | 1.2071 | 0.2120 | 0.2960 | 0.079* | |
H4C | 1.3912 | 0.2764 | 0.2288 | 0.079* | |
C5 | 0.7984 (9) | 0.8772 (5) | 0.3581 (5) | 0.0352 (13) | |
C6 | 0.6339 (9) | 0.7887 (6) | 0.2482 (5) | 0.0382 (14) | |
H6 | 0.4921 | 0.7526 | 0.2725 | 0.046* | |
C7 | 0.5854 (10) | 0.8841 (6) | 0.1529 (5) | 0.0461 (15) | |
H7 | 0.4896 | 0.9580 | 0.1732 | 0.055* | |
C8 | 0.4866 (9) | 0.7569 (6) | 0.0413 (5) | 0.0465 (16) | |
H8A | 0.3588 | 0.6890 | 0.0529 | 0.056* | |
H8B | 0.4494 | 0.7927 | −0.0306 | 0.056* | |
C9 | 0.8013 (11) | 0.9424 (7) | 0.1205 (6) | 0.0554 (18) | |
H9 | 0.8732 | 1.0420 | 0.1412 | 0.067* | |
C10 | 0.8775 (10) | 0.8277 (7) | 0.0559 (6) | 0.0509 (16) | |
H10 | 1.0100 | 0.8324 | 0.0246 | 0.061* | |
C11 | 0.7036 (9) | 0.6914 (6) | 0.0455 (5) | 0.0408 (14) | |
H11 | 0.7036 | 0.6070 | −0.0210 | 0.049* | |
C12 | 0.7108 (8) | 0.6539 (5) | 0.1701 (5) | 0.0381 (14) | |
H12 | 0.5919 | 0.5667 | 0.1603 | 0.046* | |
C13 | 0.9272 (9) | 0.6120 (5) | 0.2222 (5) | 0.0399 (14) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.053 (3) | 0.054 (3) | 0.041 (3) | −0.0001 (19) | 0.001 (2) | −0.008 (2) |
O2 | 0.039 (2) | 0.074 (3) | 0.041 (3) | −0.003 (2) | 0.0025 (18) | −0.003 (2) |
O3 | 0.041 (2) | 0.069 (3) | 0.060 (3) | 0.022 (2) | −0.008 (2) | 0.025 (2) |
O4 | 0.042 (3) | 0.084 (3) | 0.062 (3) | 0.032 (2) | 0.008 (2) | 0.021 (2) |
N1 | 0.041 (3) | 0.040 (3) | 0.041 (3) | 0.015 (2) | −0.003 (2) | 0.007 (2) |
C1 | 0.058 (4) | 0.044 (4) | 0.080 (5) | 0.029 (3) | −0.006 (4) | −0.008 (3) |
C2 | 0.042 (3) | 0.034 (3) | 0.037 (3) | 0.017 (2) | 0.003 (2) | 0.000 (2) |
C3 | 0.039 (3) | 0.032 (3) | 0.037 (3) | 0.008 (2) | 0.001 (2) | 0.006 (2) |
C4 | 0.064 (4) | 0.047 (3) | 0.041 (4) | 0.017 (3) | −0.004 (3) | 0.002 (3) |
C5 | 0.041 (3) | 0.035 (3) | 0.029 (3) | 0.014 (2) | 0.003 (2) | 0.003 (2) |
C6 | 0.029 (3) | 0.042 (3) | 0.040 (3) | 0.008 (2) | 0.002 (2) | 0.003 (2) |
C7 | 0.054 (4) | 0.042 (3) | 0.040 (3) | 0.022 (3) | −0.004 (3) | 0.004 (3) |
C8 | 0.042 (3) | 0.049 (3) | 0.041 (3) | 0.012 (2) | −0.012 (3) | 0.003 (3) |
C9 | 0.058 (4) | 0.044 (3) | 0.056 (4) | −0.003 (3) | −0.016 (3) | 0.019 (3) |
C10 | 0.038 (3) | 0.066 (4) | 0.049 (4) | 0.010 (3) | −0.007 (3) | 0.021 (3) |
C11 | 0.036 (3) | 0.039 (3) | 0.040 (3) | 0.008 (2) | −0.004 (2) | 0.000 (2) |
C12 | 0.028 (3) | 0.026 (3) | 0.047 (3) | −0.002 (2) | −0.011 (2) | −0.004 (2) |
C13 | 0.039 (3) | 0.028 (3) | 0.045 (3) | 0.007 (2) | −0.015 (3) | 0.005 (2) |
Geometric parameters (Å, º) top
O1—C5 | 1.296 (6) | C5—C6 | 1.509 (7) |
O1—H1 | 0.8200 | C6—C12 | 1.560 (7) |
O2—C5 | 1.215 (6) | C6—C7 | 1.576 (8) |
O3—C13 | 1.308 (7) | C6—H6 | 0.9800 |
O3—H3 | 0.8200 | C7—C9 | 1.476 (9) |
O4—C13 | 1.201 (7) | C7—C8 | 1.541 (8) |
N1—C2 | 1.329 (7) | C7—H7 | 0.9800 |
N1—C3 | 1.343 (7) | C8—C11 | 1.538 (8) |
C1—C2 | 1.500 (7) | C8—H8A | 0.9700 |
C1—H1A | 0.9600 | C8—H8B | 0.9700 |
C1—H1B | 0.9600 | C9—C10 | 1.352 (9) |
C1—H1C | 0.9600 | C9—H9 | 0.9300 |
C2—C3i | 1.401 (7) | C10—C11 | 1.499 (8) |
C3—C2i | 1.401 (7) | C10—H10 | 0.9300 |
C3—C4 | 1.488 (7) | C11—C12 | 1.548 (8) |
C4—H4A | 0.9600 | C11—H11 | 0.9800 |
C4—H4B | 0.9600 | C12—C13 | 1.515 (7) |
C4—H4C | 0.9600 | C12—H12 | 0.9800 |
| | | |
C5—O1—H1 | 109.5 | C8—C7—C6 | 99.7 (4) |
C13—O3—H3 | 109.5 | C9—C7—H7 | 115.4 |
C2—N1—C3 | 119.7 (4) | C8—C7—H7 | 115.4 |
C2—C1—H1A | 109.5 | C6—C7—H7 | 115.4 |
C2—C1—H1B | 109.5 | C11—C8—C7 | 93.0 (4) |
H1A—C1—H1B | 109.5 | C11—C8—H8A | 113.1 |
C2—C1—H1C | 109.5 | C7—C8—H8A | 113.1 |
H1A—C1—H1C | 109.5 | C11—C8—H8B | 113.1 |
H1B—C1—H1C | 109.5 | C7—C8—H8B | 113.1 |
N1—C2—C3i | 121.0 (5) | H8A—C8—H8B | 110.5 |
N1—C2—C1 | 117.2 (5) | C10—C9—C7 | 109.0 (5) |
C3i—C2—C1 | 121.8 (5) | C10—C9—H9 | 125.5 |
N1—C3—C2i | 119.2 (5) | C7—C9—H9 | 125.5 |
N1—C3—C4 | 117.9 (5) | C9—C10—C11 | 105.5 (6) |
C2i—C3—C4 | 122.7 (5) | C9—C10—H10 | 127.2 |
C3—C4—H4A | 109.5 | C11—C10—H10 | 127.2 |
C3—C4—H4B | 109.5 | C10—C11—C8 | 101.5 (5) |
H4A—C4—H4B | 109.5 | C10—C11—C12 | 108.9 (4) |
C3—C4—H4C | 109.5 | C8—C11—C12 | 98.1 (5) |
H4A—C4—H4C | 109.5 | C10—C11—H11 | 115.4 |
H4B—C4—H4C | 109.5 | C8—C11—H11 | 115.4 |
O2—C5—O1 | 122.8 (5) | C12—C11—H11 | 115.4 |
O2—C5—C6 | 124.0 (5) | C13—C12—C11 | 116.0 (5) |
O1—C5—C6 | 113.2 (5) | C13—C12—C6 | 116.2 (4) |
C5—C6—C12 | 116.6 (4) | C11—C12—C6 | 104.3 (4) |
C5—C6—C7 | 112.5 (4) | C13—C12—H12 | 106.5 |
C12—C6—C7 | 100.6 (4) | C11—C12—H12 | 106.5 |
C5—C6—H6 | 108.9 | C6—C12—H12 | 106.5 |
C12—C6—H6 | 108.9 | O4—C13—O3 | 123.2 (5) |
C7—C6—H6 | 108.9 | O4—C13—C12 | 124.7 (5) |
C9—C7—C8 | 100.5 (5) | O3—C13—C12 | 111.9 (6) |
C9—C7—C6 | 108.3 (5) | | |
Symmetry code: (i) −x+3, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O2ii | 0.82 | 1.88 | 2.696 (5) | 174 |
O3—H3···N1 | 0.82 | 1.92 | 2.715 (5) | 164 |
C1—H1C···O3 | 0.96 | 2.59 | 3.399 (5) | 142 |
C8—H8A···O4iii | 0.97 | 2.46 | 3.361 (5) | 154 |
Symmetry codes: (ii) −x+2, −y+2, −z+1; (iii) x−1, y, z. |