Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807034502/bi2210sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807034502/bi2210Isup2.hkl |
CCDC reference: 657799
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.003 Å
- R factor = 0.055
- wR factor = 0.154
- Data-to-parameter ratio = 12.4
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
Alert level G PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 2 ALERT level G = General alerts; check 3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
An anhydrous ethanol solution (50 ml) of 5-nitrofuran-2-carbaldehyde (1.41 g,10 mmol) was added to an anhydrous ethanol solution (50 ml) of 4-amino-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (2.03 g, 10 mmol) and the mixture was stirred at 350 K for 6 h under N2, forming a red solution. The solvent was removed and the residue was recrystallized from anhydrous ethanol then dried in vacuo to give the title compound in 88% yield. Red single crystals suitable for X-ray analysis were obtained by slow evaporation of an anhydrous ethanol solution.
H atoms were included in calculated positions, with C—H = 0.93 (aromatic) or 0.96 Å (methyl), and refined using a riding model, with Uiso(H) = 1.2Ueq(aromatic C) or 1.5Ueq(methyl C). The methyl groups were allowed to rotate about their local threefold axes.
Metal complexes based on Schiff bases have attracted much attention because they can be utilized as model compounds of active centres in various proteins and enzymes (Kahwa et al., 1986; Santos et al.,2001). As part of an investigation of the coordination properties of Shiff bases functioning as ligands, we report the synthesis and structure of the title compound.
The molecular structure (Figure 1) has expected geometric parameters. The central chromophore (C6–C8/N3/N4) is planar, with an r.m.s. deviation for the fitted atoms of 0.0253 (2) Å. The 5-nitrofuran-2-carbaldehyde group (C1–C4/O3) and phenyl ring (C11–C16) are also planar, with r.m.s. deviations of 0.0013 (3) and 0.0084 (4) Å, respectively. The dihedral angles between these latter two planes and the plane through the C6–C8/N3/N4 ring are 5.66 (6)° and 46.54 (5)°, respectively, while the C1–C4/O3 and C11–C16 planes form an angle of 46.97 (4) Å. The molecules adopt a layered arrangement (Figure 2), with C—H···O interactions formed to the NO2 group.
For related literature, see: Kahwa et al. (1986); Santos et al. (2001).
Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: CrystalStructure (Rigaku/MSC, 2005); software used to prepare material for publication: CrystalStructure.
C16H14N4O4 | F(000) = 680 |
Mr = 326.31 | Dx = 1.406 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 3365 reflections |
a = 7.0722 (14) Å | θ = 2.6–27.9° |
b = 7.8143 (16) Å | µ = 0.10 mm−1 |
c = 27.917 (6) Å | T = 293 K |
β = 91.75 (3)° | Block, red |
V = 1542.1 (6) Å3 | 0.10 × 0.08 × 0.04 mm |
Z = 4 |
Rigaku Saturn CCD diffractometer | 2723 independent reflections |
Radiation source: rotating anode | 2175 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.047 |
ω scans | θmax = 25.0°, θmin = 1.5° |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | h = −8→8 |
Tmin = 0.990, Tmax = 0.996 | k = −9→9 |
9081 measured reflections | l = −33→25 |
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: inferred from neighbouring sites |
wR(F2) = 0.154 | H-atom parameters constrained |
S = 1.17 | w = 1/[σ2(Fo2) + (0.0739P)2 + 0.2344P] where P = (Fo2 + 2Fc2)/3 |
2723 reflections | (Δ/σ)max = 0.005 |
219 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.32 e Å−3 |
C16H14N4O4 | V = 1542.1 (6) Å3 |
Mr = 326.31 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 7.0722 (14) Å | µ = 0.10 mm−1 |
b = 7.8143 (16) Å | T = 293 K |
c = 27.917 (6) Å | 0.10 × 0.08 × 0.04 mm |
β = 91.75 (3)° |
Rigaku Saturn CCD diffractometer | 2723 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | 2175 reflections with I > 2σ(I) |
Tmin = 0.990, Tmax = 0.996 | Rint = 0.047 |
9081 measured reflections |
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.154 | H-atom parameters constrained |
S = 1.17 | Δρmax = 0.25 e Å−3 |
2723 reflections | Δρmin = −0.32 e Å−3 |
219 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 | ||
O1 | 0.6509 (3) | 0.9463 (2) | 1.07595 (9) | 0.0716 (7) | |
O2 | 0.5483 (3) | 0.8358 (3) | 1.14189 (8) | 0.0708 (7) | |
O3 | 0.7068 (2) | 0.64324 (18) | 1.03917 (6) | 0.0381 (4) | |
O4 | 0.8983 (3) | 0.4723 (2) | 0.88083 (6) | 0.0466 (5) | |
N1 | 0.6087 (3) | 0.8236 (3) | 1.10124 (9) | 0.0507 (6) | |
N2 | 0.7851 (3) | 0.2637 (2) | 0.97211 (6) | 0.0353 (5) | |
N3 | 0.9515 (3) | 0.1961 (2) | 0.85268 (7) | 0.0373 (5) | |
N4 | 0.9140 (3) | 0.0287 (2) | 0.86905 (7) | 0.0370 (5) | |
C1 | 0.6319 (3) | 0.6556 (3) | 1.08303 (8) | 0.0374 (6) | |
C2 | 0.5889 (4) | 0.5012 (3) | 1.10137 (9) | 0.0423 (6) | |
H2 | 0.5368 | 0.4791 | 1.1309 | 0.051* | |
C3 | 0.6386 (4) | 0.3810 (3) | 1.06675 (8) | 0.0406 (6) | |
H3 | 0.6253 | 0.2629 | 1.0688 | 0.049* | |
C4 | 0.7105 (3) | 0.4706 (3) | 1.02929 (8) | 0.0342 (5) | |
C5 | 0.7813 (3) | 0.4231 (3) | 0.98341 (8) | 0.0350 (6) | |
H5 | 0.8235 | 0.5060 | 0.9624 | 0.042* | |
C6 | 0.8485 (3) | 0.2121 (3) | 0.92785 (8) | 0.0327 (5) | |
C7 | 0.8621 (3) | 0.0419 (3) | 0.91528 (8) | 0.0345 (5) | |
C8 | 0.8995 (3) | 0.3150 (3) | 0.88740 (8) | 0.0341 (5) | |
C9 | 0.8329 (4) | −0.1113 (3) | 0.94581 (10) | 0.0501 (7) | |
H9A | 0.7707 | −0.1991 | 0.9271 | 0.075* | |
H9B | 0.7561 | −0.0810 | 0.9723 | 0.075* | |
H9C | 0.9532 | −0.1528 | 0.9577 | 0.075* | |
C10 | 1.0214 (4) | −0.1151 (3) | 0.84999 (10) | 0.0463 (6) | |
H10A | 1.1541 | −0.0966 | 0.8562 | 0.069* | |
H10B | 0.9973 | −0.1237 | 0.8160 | 0.069* | |
H10C | 0.9833 | −0.2192 | 0.8652 | 0.069* | |
C11 | 0.9627 (3) | 0.2297 (3) | 0.80267 (8) | 0.0366 (6) | |
C12 | 0.8539 (4) | 0.1400 (3) | 0.76909 (9) | 0.0450 (6) | |
H12 | 0.7689 | 0.0572 | 0.7789 | 0.054* | |
C13 | 0.8724 (4) | 0.1746 (3) | 0.72060 (9) | 0.0524 (7) | |
H13 | 0.8021 | 0.1126 | 0.6979 | 0.063* | |
C14 | 0.9938 (4) | 0.2999 (3) | 0.70615 (10) | 0.0535 (7) | |
H14 | 1.0057 | 0.3226 | 0.6737 | 0.064* | |
C15 | 1.0986 (4) | 0.3926 (3) | 0.73983 (10) | 0.0520 (7) | |
H15 | 1.1781 | 0.4797 | 0.7299 | 0.062* | |
C16 | 1.0858 (4) | 0.3564 (3) | 0.78811 (9) | 0.0453 (6) | |
H16 | 1.1591 | 0.4166 | 0.8106 | 0.054* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0948 (18) | 0.0325 (11) | 0.0871 (16) | −0.0013 (10) | −0.0040 (13) | −0.0034 (10) |
O2 | 0.0737 (15) | 0.0753 (15) | 0.0635 (14) | 0.0122 (11) | 0.0050 (12) | −0.0309 (11) |
O3 | 0.0455 (10) | 0.0303 (8) | 0.0387 (9) | −0.0018 (7) | 0.0023 (7) | 0.0004 (7) |
O4 | 0.0676 (13) | 0.0290 (9) | 0.0437 (10) | −0.0025 (8) | 0.0109 (9) | 0.0037 (7) |
N1 | 0.0510 (14) | 0.0420 (13) | 0.0585 (15) | 0.0044 (10) | −0.0068 (12) | −0.0146 (11) |
N2 | 0.0389 (11) | 0.0359 (11) | 0.0311 (10) | −0.0004 (8) | 0.0016 (8) | 0.0018 (8) |
N3 | 0.0514 (12) | 0.0288 (10) | 0.0322 (10) | −0.0041 (9) | 0.0088 (9) | 0.0047 (8) |
N4 | 0.0469 (12) | 0.0254 (10) | 0.0391 (11) | −0.0016 (8) | 0.0064 (9) | 0.0022 (8) |
C1 | 0.0384 (13) | 0.0385 (13) | 0.0355 (13) | −0.0003 (10) | 0.0006 (10) | −0.0060 (10) |
C2 | 0.0474 (15) | 0.0443 (14) | 0.0355 (13) | −0.0001 (11) | 0.0053 (11) | 0.0018 (10) |
C3 | 0.0508 (15) | 0.0318 (12) | 0.0393 (14) | 0.0000 (10) | 0.0052 (11) | 0.0049 (10) |
C4 | 0.0355 (13) | 0.0289 (11) | 0.0381 (13) | 0.0008 (9) | −0.0019 (10) | −0.0010 (9) |
C5 | 0.0363 (14) | 0.0362 (13) | 0.0324 (12) | −0.0016 (10) | 0.0002 (10) | 0.0041 (9) |
C6 | 0.0351 (13) | 0.0296 (12) | 0.0337 (12) | −0.0006 (9) | 0.0032 (10) | 0.0023 (9) |
C7 | 0.0363 (13) | 0.0335 (12) | 0.0337 (12) | −0.0011 (10) | 0.0013 (10) | 0.0025 (9) |
C8 | 0.0382 (13) | 0.0292 (12) | 0.0351 (12) | −0.0024 (9) | 0.0020 (10) | 0.0007 (9) |
C9 | 0.0706 (19) | 0.0340 (13) | 0.0461 (15) | −0.0027 (12) | 0.0076 (13) | 0.0088 (11) |
C10 | 0.0572 (17) | 0.0329 (13) | 0.0492 (15) | 0.0031 (11) | 0.0075 (12) | −0.0042 (11) |
C11 | 0.0406 (14) | 0.0360 (12) | 0.0337 (12) | 0.0025 (10) | 0.0091 (10) | 0.0028 (9) |
C12 | 0.0497 (16) | 0.0396 (14) | 0.0457 (15) | −0.0061 (11) | 0.0042 (12) | 0.0021 (11) |
C13 | 0.0683 (19) | 0.0502 (15) | 0.0385 (14) | 0.0023 (14) | −0.0031 (13) | −0.0041 (12) |
C14 | 0.073 (2) | 0.0522 (16) | 0.0368 (14) | 0.0094 (14) | 0.0157 (13) | 0.0059 (12) |
C15 | 0.0587 (18) | 0.0511 (15) | 0.0473 (16) | −0.0062 (13) | 0.0207 (13) | 0.0080 (12) |
C16 | 0.0486 (16) | 0.0461 (14) | 0.0415 (14) | −0.0078 (12) | 0.0072 (12) | 0.0018 (11) |
O1—N1 | 1.233 (3) | C6—C7 | 1.380 (3) |
O2—N1 | 1.229 (3) | C6—C8 | 1.441 (3) |
O3—C1 | 1.352 (3) | C7—C9 | 1.488 (3) |
O3—C4 | 1.378 (3) | C9—H9A | 0.960 |
O4—C8 | 1.242 (3) | C9—H9B | 0.960 |
N1—C1 | 1.419 (3) | C9—H9C | 0.960 |
N2—C5 | 1.285 (3) | C10—H10A | 0.960 |
N2—C6 | 1.387 (3) | C10—H10B | 0.960 |
N3—C8 | 1.400 (3) | C10—H10C | 0.960 |
N3—N4 | 1.413 (2) | C11—C12 | 1.385 (3) |
N3—C11 | 1.425 (3) | C11—C16 | 1.388 (3) |
N4—C7 | 1.357 (3) | C12—C13 | 1.390 (4) |
N4—C10 | 1.466 (3) | C12—H12 | 0.930 |
C1—C2 | 1.349 (3) | C13—C14 | 1.371 (4) |
C2—C3 | 1.400 (4) | C13—H13 | 0.930 |
C2—H2 | 0.930 | C14—C15 | 1.384 (4) |
C3—C4 | 1.369 (3) | C14—H14 | 0.930 |
C3—H3 | 0.930 | C15—C16 | 1.383 (4) |
C4—C5 | 1.438 (3) | C15—H15 | 0.930 |
C5—H5 | 0.930 | C16—H16 | 0.930 |
C1—O3—C4 | 105.17 (17) | O4—C8—C6 | 131.8 (2) |
O2—N1—O1 | 124.4 (2) | N3—C8—C6 | 104.42 (19) |
O2—N1—C1 | 116.8 (2) | C7—C9—H9A | 109.5 |
O1—N1—C1 | 118.8 (2) | C7—C9—H9B | 109.5 |
C5—N2—C6 | 120.64 (19) | H9A—C9—H9B | 109.5 |
C8—N3—N4 | 109.55 (18) | C7—C9—H9C | 109.5 |
C8—N3—C11 | 125.39 (19) | H9A—C9—H9C | 109.5 |
N4—N3—C11 | 120.27 (18) | H9B—C9—H9C | 109.5 |
C7—N4—N3 | 107.26 (17) | N4—C10—H10A | 109.5 |
C7—N4—C10 | 124.19 (19) | N4—C10—H10B | 109.5 |
N3—N4—C10 | 119.18 (19) | H10A—C10—H10B | 109.5 |
C2—C1—O3 | 112.3 (2) | N4—C10—H10C | 109.5 |
C2—C1—N1 | 131.4 (2) | H10A—C10—H10C | 109.5 |
O3—C1—N1 | 116.3 (2) | H10B—C10—H10C | 109.5 |
C1—C2—C3 | 105.9 (2) | C12—C11—C16 | 120.2 (2) |
C1—C2—H2 | 127.1 | C12—C11—N3 | 121.6 (2) |
C3—C2—H2 | 127.1 | C16—C11—N3 | 118.2 (2) |
C4—C3—C2 | 107.0 (2) | C11—C12—C13 | 119.6 (2) |
C4—C3—H3 | 126.5 | C11—C12—H12 | 120.2 |
C2—C3—H3 | 126.5 | C13—C12—H12 | 120.2 |
C3—C4—O3 | 109.8 (2) | C14—C13—C12 | 120.3 (2) |
C3—C4—C5 | 134.1 (2) | C14—C13—H13 | 119.9 |
O3—C4—C5 | 116.1 (2) | C12—C13—H13 | 119.9 |
N2—C5—C4 | 118.6 (2) | C13—C14—C15 | 120.1 (3) |
N2—C5—H5 | 120.7 | C13—C14—H14 | 120.0 |
C4—C5—H5 | 120.7 | C15—C14—H14 | 120.0 |
C7—C6—N2 | 122.2 (2) | C16—C15—C14 | 120.4 (3) |
C7—C6—C8 | 108.5 (2) | C16—C15—H15 | 119.8 |
N2—C6—C8 | 129.1 (2) | C14—C15—H15 | 119.8 |
N4—C7—C6 | 109.74 (19) | C15—C16—C11 | 119.4 (2) |
N4—C7—C9 | 122.0 (2) | C15—C16—H16 | 120.3 |
C6—C7—C9 | 128.2 (2) | C11—C16—H16 | 120.3 |
O4—C8—N3 | 123.7 (2) | ||
C8—N3—N4—C7 | −7.3 (2) | C10—N4—C7—C9 | −27.0 (3) |
C11—N3—N4—C7 | −164.1 (2) | N2—C6—C7—N4 | 175.44 (19) |
C8—N3—N4—C10 | −155.3 (2) | C8—C6—C7—N4 | −1.4 (3) |
C11—N3—N4—C10 | 48.0 (3) | N2—C6—C7—C9 | −6.5 (4) |
C4—O3—C1—C2 | 0.2 (3) | C8—C6—C7—C9 | 176.7 (2) |
C4—O3—C1—N1 | −178.63 (19) | N4—N3—C8—O4 | −172.3 (2) |
O2—N1—C1—C2 | 4.5 (4) | C11—N3—C8—O4 | −17.0 (4) |
O1—N1—C1—C2 | −176.1 (3) | N4—N3—C8—C6 | 6.2 (2) |
O2—N1—C1—O3 | −177.0 (2) | C11—N3—C8—C6 | 161.5 (2) |
O1—N1—C1—O3 | 2.5 (3) | C7—C6—C8—O4 | 175.4 (2) |
O3—C1—C2—C3 | −0.3 (3) | N2—C6—C8—O4 | −1.2 (4) |
N1—C1—C2—C3 | 178.2 (2) | C7—C6—C8—N3 | −3.0 (2) |
C1—C2—C3—C4 | 0.4 (3) | N2—C6—C8—N3 | −179.6 (2) |
C2—C3—C4—O3 | −0.3 (3) | C8—N3—C11—C12 | −120.2 (3) |
C2—C3—C4—C5 | −178.5 (2) | N4—N3—C11—C12 | 32.7 (3) |
C1—O3—C4—C3 | 0.1 (2) | C8—N3—C11—C16 | 59.5 (3) |
C1—O3—C4—C5 | 178.64 (19) | N4—N3—C11—C16 | −147.6 (2) |
C6—N2—C5—C4 | 178.65 (19) | C16—C11—C12—C13 | 1.7 (4) |
C3—C4—C5—N2 | −0.8 (4) | N3—C11—C12—C13 | −178.6 (2) |
O3—C4—C5—N2 | −178.96 (19) | C11—C12—C13—C14 | −1.8 (4) |
C5—N2—C6—C7 | 177.2 (2) | C12—C13—C14—C15 | 0.0 (4) |
C5—N2—C6—C8 | −6.6 (4) | C13—C14—C15—C16 | 1.9 (4) |
N3—N4—C7—C6 | 5.3 (3) | C14—C15—C16—C11 | −1.9 (4) |
C10—N4—C7—C6 | 151.2 (2) | C12—C11—C16—C15 | 0.1 (4) |
N3—N4—C7—C9 | −172.9 (2) | N3—C11—C16—C15 | −179.6 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.93 | 2.49 | 3.407 (3) | 170 |
Symmetry code: (i) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | C16H14N4O4 |
Mr | 326.31 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 7.0722 (14), 7.8143 (16), 27.917 (6) |
β (°) | 91.75 (3) |
V (Å3) | 1542.1 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.10 × 0.08 × 0.04 |
Data collection | |
Diffractometer | Rigaku Saturn CCD |
Absorption correction | Multi-scan (CrystalClear; Rigaku/MSC, 2005) |
Tmin, Tmax | 0.990, 0.996 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9081, 2723, 2175 |
Rint | 0.047 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.154, 1.17 |
No. of reflections | 2723 |
No. of parameters | 219 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.32 |
Computer programs: CrystalClear (Rigaku/MSC, 2005), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), CrystalStructure (Rigaku/MSC, 2005), CrystalStructure.
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.93 | 2.49 | 3.407 (3) | 170 |
Symmetry code: (i) x, y−1, z. |
Metal complexes based on Schiff bases have attracted much attention because they can be utilized as model compounds of active centres in various proteins and enzymes (Kahwa et al., 1986; Santos et al.,2001). As part of an investigation of the coordination properties of Shiff bases functioning as ligands, we report the synthesis and structure of the title compound.
The molecular structure (Figure 1) has expected geometric parameters. The central chromophore (C6–C8/N3/N4) is planar, with an r.m.s. deviation for the fitted atoms of 0.0253 (2) Å. The 5-nitrofuran-2-carbaldehyde group (C1–C4/O3) and phenyl ring (C11–C16) are also planar, with r.m.s. deviations of 0.0013 (3) and 0.0084 (4) Å, respectively. The dihedral angles between these latter two planes and the plane through the C6–C8/N3/N4 ring are 5.66 (6)° and 46.54 (5)°, respectively, while the C1–C4/O3 and C11–C16 planes form an angle of 46.97 (4) Å. The molecules adopt a layered arrangement (Figure 2), with C—H···O interactions formed to the NO2 group.