organic compounds
6-Nitro-1,10-phenanthrolin-5-amine
aDepartment of Chemistry, Unversity of the Free State, PO Box 339, Bloemfontein, 9301, South Africa
*Correspondence e-mail: visserhg@ufs.ac.za
In the title compound, C12H8N4O2, the dihedral angle between the phenanthroline ring system and the nitro group is 23.75 (14)°. The molecule features intramolecular N—H⋯O and C—H⋯O hydrogen bonds. In the crystal, N—H⋯(N,N), C—H⋯N and C—H⋯O hydrogen bonds link the molecules into [100] chains.
Keywords: crystal structure; phenanthroline; functionalization; bidentate ligands.
CCDC reference: 1940842
Structure description
When 1,10-phenanthroline coordinates to transition metals, it forms thermally and chemically stable complexes. The combination of electronic transitions of the metal and the conjugated π- electron system of 1,10-phenanthroline leads to complexes with interesting photophysical, photochemical and electrochemical properties. To expand this chemistry, the synthesis of 1,10-phenanthroline derivatives with substituents on positions 3 to 8 is necessary (Khimich et al., 2006). The title compound is formed by the amination of 5-nitro-1,10-phenanthroline using ethanol and dioxane. The use of phendiamine (1,10-phenanthroline-5,6-diamine) as an N,N′-bidentate ligand was one of the main aims in the study. Phendiamine can be coordinated to two metal centres and can act as a bridging ligand. 5-Amino-6-nitro-1,10-phenanthroline is comparable to phendione (1,10-phenanthroline-5,6-dione) and 5-nitro-1,10-phenanthroline.
The title compound crystallizes in Pbca with one molecule in the (Fig. 1). The nitro group is twisted from the rest of the molecule by 23.75 (14)°. The O atoms of the nitro group accept intramolecular hydrogen bonds from the adjacent NH and CH groups (Table 1).
In the extended structure, there are no π–π stacking interactions but infinite chains are observed propagating along the a-axis direction via N3—H4A⋯(N1,N2), C3—H3⋯N1 and C9—H7⋯O1 interactions (Table 1, Fig. 2). Adjacent molecules in the chain are rotated by approximately 90° with respect to each other (Fig. 3).
A search of the Cambridge Structural Database (Version 5.32, update Feb 2011, Groom et al., 2016) for 1,10-phenanthroline derivatives with nitrogen atoms on positions 5 and 6 gave 136 hits, with a variety of substituents on the nitrogen atoms. One of these structures, N′′,N′′′-1,10-phenanthroline-5,6-diylbis (N,N,N′,N′-tetramethylguanidine) reported by Ortmeyer et al., (2017) (refcode ZEQREV) has similar bond distances and angles to those in the title compound.
Synthesis and crystallization
The synthesis of the title compound was achieved according to the literature method of Bolger et al. (1996). 5-Nitro-1,10-phenanthroline (3.49 g, 15.5 mmol) was dissolved in a mixture of 100 ml of ethanol/dioxane (3:2) and heated to 60°C until all the solids were dissolved. It was rapidly cooled to 4°C and formed a fine suspension. Powdered hydroxyl amine hydrochloride (6.84 g, 9.84 mmol) was added, followed by the dropwise addition of KOH (7.27 g, 129.5 mmol) in methanol (100 ml). The solution was stirred at 4°C for one hour and then heated to 60°C for another hour. The solution was poured onto ice and resulted in the formation of a yellow precipitate, which was washed with water and methanol after filtration. Yellow single crystals suitable for X-ray diffraction were obtained in chloroform at room temperature. Yield: 0.5441 g (14%). IR (ATR, cm−1): 1626, 1523, 1486, 1433, 1383, 1302, 1260, 1172, 1095, 827, 796, 734, 670. 1H NMR (300 MHz, DMSO-d6): δ 9.2 (dd, J = 1.35, 4.26 Hz, 1H), 9.1 (dd, J = 1.36, 8.44 Hz, 1H), 8.8 (dd, J = 1.47, 4.27 Hz, 1H), 8.7 (dd, J = 1.48, 8.58 Hz, 1H), 8.6 (s, 2H), 7.9 (dd, J = 4.27, 8.46 Hz, 1H) and 7.7 (dd, J = 4.15, 8.46 Hz, 1H). 13C NMR (600 MHz, DMSO-d6): δ 154, 148, 147, 144, 140, 137, 134, 131, 125, 124, 123, 121. UV/Vis: ∊ (λmax = 419 nm) = 19985 M−1 cm−1.
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2
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Structural data
CCDC reference: 1940842
https://doi.org/10.1107/S2414314619010162/hb4300sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314619010162/hb4300Isup2.hkl
Data collection: APEX2 (Bruker, 2012); cell
SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).C12H8N4O2 | F(000) = 992 |
Mr = 240.22 | Dx = 1.58 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 1396 reflections |
a = 14.265 (8) Å | θ = 3.7–23.4° |
b = 8.060 (4) Å | µ = 0.11 mm−1 |
c = 17.564 (9) Å | T = 100 K |
V = 2019.4 (19) Å3 | Cuboid, yellow |
Z = 8 | 0.37 × 0.12 × 0.09 mm |
Bruker APEXII CCD diffractometer | 1204 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.093 |
Absorption correction: multi-scan (SADABS; Bruker, 2012) | θmax = 28.0°, θmin = 4.0° |
Tmin = 0.984, Tmax = 0.99 | h = −18→18 |
13477 measured reflections | k = −7→10 |
2426 independent reflections | l = −22→23 |
Refinement on F2 | Hydrogen site location: mixed |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.058 | w = 1/[σ2(Fo2) + (0.0669P)2 + 0.4998P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.176 | (Δ/σ)max < 0.001 |
S = 1.03 | Δρmax = 0.36 e Å−3 |
2426 reflections | Δρmin = −0.39 e Å−3 |
172 parameters | Extinction correction: SHELXL-2018/3 (Sheldrick 2015) |
0 restraints | Extinction coefficient: 0.0047 (14) |
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. Aromatic H atoms were positioned geometrically with a C—H distance of 0.95 Å and constrained to ride on their parent atoms with Uiso (H) = 1.2 Ueq(C). |
x | y | z | Uiso*/Ueq | ||
N1 | 0.40826 (14) | 0.4435 (3) | 0.33237 (13) | 0.0383 (6) | |
C12 | 0.26583 (16) | 0.3587 (3) | 0.27163 (14) | 0.0286 (6) | |
C6 | 0.15781 (17) | 0.5134 (3) | 0.38771 (14) | 0.0309 (6) | |
C7 | 0.25963 (17) | 0.5190 (3) | 0.39240 (14) | 0.0300 (6) | |
C11 | 0.31313 (17) | 0.4415 (3) | 0.33443 (15) | 0.0305 (6) | |
C4 | 0.16718 (16) | 0.3585 (3) | 0.26734 (14) | 0.0284 (6) | |
N2 | 0.32090 (15) | 0.2864 (3) | 0.21825 (13) | 0.0356 (6) | |
N3 | 0.01725 (16) | 0.4325 (3) | 0.31972 (18) | 0.0445 (7) | |
C5 | 0.11029 (17) | 0.4399 (3) | 0.32623 (15) | 0.0311 (6) | |
O1 | 0.02003 (14) | 0.6244 (3) | 0.43663 (12) | 0.0562 (7) | |
N4 | 0.10335 (16) | 0.5857 (3) | 0.44757 (14) | 0.0421 (6) | |
C9 | 0.40771 (19) | 0.6088 (4) | 0.44486 (17) | 0.0458 (8) | |
H7 | 0.442575 | 0.66799 | 0.482097 | 0.055* | |
C8 | 0.31192 (19) | 0.6052 (4) | 0.44809 (16) | 0.0404 (7) | |
H6 | 0.280266 | 0.661066 | 0.488166 | 0.048* | |
C1 | 0.27861 (19) | 0.2137 (4) | 0.15956 (15) | 0.0393 (7) | |
H1 | 0.316626 | 0.164069 | 0.121416 | 0.047* | |
C3 | 0.12573 (19) | 0.2785 (3) | 0.20499 (15) | 0.0364 (7) | |
H3 | 0.059429 | 0.274357 | 0.200254 | 0.044* | |
C2 | 0.18162 (19) | 0.2063 (4) | 0.15100 (16) | 0.0383 (7) | |
H2 | 0.154655 | 0.151906 | 0.108296 | 0.046* | |
C10 | 0.4533 (2) | 0.5254 (4) | 0.38678 (18) | 0.0471 (8) | |
H8 | 0.51987 | 0.526878 | 0.385799 | 0.057* | |
O2 | 0.13845 (16) | 0.6016 (4) | 0.51179 (13) | 0.0786 (9) | |
H4A | −0.009 (2) | 0.385 (4) | 0.2794 (19) | 0.062 (11)* | |
H4B | −0.020 (3) | 0.483 (5) | 0.356 (2) | 0.089 (13)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0250 (12) | 0.0449 (14) | 0.0449 (15) | −0.0012 (10) | −0.0059 (10) | −0.0005 (11) |
C12 | 0.0267 (13) | 0.0276 (13) | 0.0316 (15) | 0.0004 (10) | −0.0020 (11) | 0.0042 (11) |
C6 | 0.0295 (14) | 0.0318 (15) | 0.0314 (16) | 0.0029 (11) | 0.0023 (11) | 0.0023 (11) |
C7 | 0.0311 (13) | 0.0289 (13) | 0.0299 (15) | 0.0011 (10) | −0.0031 (11) | 0.0039 (11) |
C11 | 0.0241 (13) | 0.0319 (14) | 0.0357 (17) | −0.0018 (10) | −0.0045 (11) | 0.0059 (12) |
C4 | 0.0250 (13) | 0.0297 (13) | 0.0305 (15) | −0.0010 (11) | −0.0015 (11) | 0.0049 (11) |
N2 | 0.0286 (12) | 0.0423 (14) | 0.0359 (14) | 0.0018 (10) | 0.0011 (10) | −0.0001 (11) |
N3 | 0.0244 (12) | 0.0594 (17) | 0.0496 (18) | 0.0033 (11) | −0.0012 (12) | −0.0095 (14) |
C5 | 0.0249 (13) | 0.0335 (14) | 0.0349 (16) | −0.0005 (10) | 0.0005 (11) | 0.0040 (12) |
O1 | 0.0419 (12) | 0.0726 (16) | 0.0540 (15) | 0.0196 (11) | 0.0072 (10) | −0.0093 (11) |
N4 | 0.0380 (14) | 0.0534 (16) | 0.0349 (15) | −0.0023 (12) | 0.0047 (12) | −0.0033 (11) |
C9 | 0.0395 (17) | 0.0499 (19) | 0.048 (2) | −0.0064 (14) | −0.0132 (14) | −0.0088 (15) |
C8 | 0.0392 (16) | 0.0405 (16) | 0.0415 (18) | −0.0008 (13) | −0.0048 (13) | −0.0052 (13) |
C1 | 0.0400 (16) | 0.0447 (17) | 0.0331 (17) | 0.0039 (13) | 0.0041 (13) | 0.0003 (13) |
C3 | 0.0293 (14) | 0.0395 (16) | 0.0405 (17) | −0.0023 (12) | −0.0049 (12) | 0.0011 (13) |
C2 | 0.0392 (15) | 0.0423 (17) | 0.0333 (17) | −0.0042 (13) | −0.0035 (12) | −0.0008 (13) |
C10 | 0.0269 (14) | 0.0532 (19) | 0.061 (2) | −0.0059 (13) | −0.0116 (14) | −0.0047 (16) |
O2 | 0.0519 (15) | 0.142 (3) | 0.0419 (15) | −0.0144 (15) | 0.0048 (12) | −0.0285 (14) |
N1—C10 | 1.327 (3) | N3—H4A | 0.89 (3) |
N1—C11 | 1.358 (3) | N3—H4B | 0.93 (4) |
C12—N2 | 1.355 (3) | O1—N4 | 1.244 (3) |
C12—C4 | 1.409 (3) | N4—O2 | 1.241 (3) |
C12—C11 | 1.455 (3) | C9—C8 | 1.368 (4) |
C6—C5 | 1.406 (4) | C9—C10 | 1.384 (4) |
C6—N4 | 1.431 (3) | C9—H7 | 0.95 |
C6—C7 | 1.456 (3) | C8—H6 | 0.95 |
C7—C8 | 1.413 (4) | C1—C2 | 1.393 (4) |
C7—C11 | 1.418 (4) | C1—H1 | 0.95 |
C4—C3 | 1.402 (4) | C3—C2 | 1.369 (4) |
C4—C5 | 1.469 (4) | C3—H3 | 0.95 |
N2—C1 | 1.331 (3) | C2—H2 | 0.95 |
N3—C5 | 1.333 (3) | C10—H8 | 0.95 |
C10—N1—C11 | 118.1 (2) | C6—C5—C4 | 117.5 (2) |
N2—C12—C4 | 122.8 (2) | O2—N4—O1 | 120.0 (2) |
N2—C12—C11 | 116.9 (2) | O2—N4—C6 | 119.4 (2) |
C4—C12—C11 | 120.3 (2) | O1—N4—C6 | 120.5 (2) |
C5—C6—N4 | 118.3 (2) | C8—C9—C10 | 119.3 (3) |
C5—C6—C7 | 122.5 (2) | C8—C9—H7 | 120.4 |
N4—C6—C7 | 119.2 (2) | C10—C9—H7 | 120.4 |
C8—C7—C11 | 115.5 (2) | C9—C8—C7 | 120.6 (3) |
C8—C7—C6 | 125.6 (2) | C9—C8—H6 | 119.7 |
C11—C7—C6 | 118.9 (2) | C7—C8—H6 | 119.7 |
N1—C11—C7 | 123.5 (2) | N2—C1—C2 | 123.6 (3) |
N1—C11—C12 | 116.7 (2) | N2—C1—H1 | 118.2 |
C7—C11—C12 | 119.8 (2) | C2—C1—H1 | 118.2 |
C3—C4—C12 | 117.6 (2) | C2—C3—C4 | 119.4 (2) |
C3—C4—C5 | 121.5 (2) | C2—C3—H3 | 120.3 |
C12—C4—C5 | 120.9 (2) | C4—C3—H3 | 120.3 |
C1—N2—C12 | 117.6 (2) | C3—C2—C1 | 119.1 (3) |
C5—N3—H4A | 121 (2) | C3—C2—H2 | 120.5 |
C5—N3—H4B | 119 (2) | C1—C2—H2 | 120.5 |
H4A—N3—H4B | 120 (3) | N1—C10—C9 | 123.0 (3) |
N3—C5—C6 | 124.4 (3) | N1—C10—H8 | 118.5 |
N3—C5—C4 | 118.0 (3) | C9—C10—H8 | 118.5 |
C5—C6—C7—C8 | 173.1 (3) | C7—C6—C5—N3 | −179.8 (2) |
N4—C6—C7—C8 | −6.7 (4) | N4—C6—C5—C4 | −176.8 (2) |
C5—C6—C7—C11 | −2.7 (4) | C7—C6—C5—C4 | 3.4 (4) |
N4—C6—C7—C11 | 177.5 (2) | C3—C4—C5—N3 | 1.4 (4) |
C10—N1—C11—C7 | −1.4 (4) | C12—C4—C5—N3 | −178.7 (2) |
C10—N1—C11—C12 | 176.6 (2) | C3—C4—C5—C6 | 178.4 (2) |
C8—C7—C11—N1 | 1.9 (4) | C12—C4—C5—C6 | −1.7 (4) |
C6—C7—C11—N1 | 178.2 (2) | C5—C6—N4—O2 | 156.5 (3) |
C8—C7—C11—C12 | −176.0 (2) | C7—C6—N4—O2 | −23.7 (4) |
C6—C7—C11—C12 | 0.2 (3) | C5—C6—N4—O1 | −19.7 (4) |
N2—C12—C11—N1 | 2.2 (3) | C7—C6—N4—O1 | 160.1 (3) |
C4—C12—C11—N1 | −176.7 (2) | C10—C9—C8—C7 | −0.7 (4) |
N2—C12—C11—C7 | −179.7 (2) | C11—C7—C8—C9 | −0.8 (4) |
C4—C12—C11—C7 | 1.4 (4) | C6—C7—C8—C9 | −176.7 (3) |
N2—C12—C4—C3 | 0.4 (4) | C12—N2—C1—C2 | −1.0 (4) |
C11—C12—C4—C3 | 179.2 (2) | C12—C4—C3—C2 | −0.7 (4) |
N2—C12—C4—C5 | −179.4 (2) | C5—C4—C3—C2 | 179.1 (2) |
C11—C12—C4—C5 | −0.6 (4) | C4—C3—C2—C1 | 0.2 (4) |
C4—C12—N2—C1 | 0.4 (4) | N2—C1—C2—C3 | 0.6 (4) |
C11—C12—N2—C1 | −178.4 (2) | C11—N1—C10—C9 | −0.3 (4) |
N4—C6—C5—N3 | −0.1 (4) | C8—C9—C10—N1 | 1.4 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H4A···N1i | 0.89 (3) | 2.34 (3) | 3.092 (4) | 143 (3) |
N3—H4A···N2i | 0.89 (3) | 2.55 (3) | 3.111 (4) | 122 (2) |
N3—H4B···O1 | 0.93 (4) | 1.90 (4) | 2.571 (4) | 127 (3) |
C3—H3···N1i | 0.95 | 2.61 | 3.438 (4) | 145 |
C8—H6···O2 | 0.95 | 2.12 | 2.716 (4) | 119 |
C9—H7···O1ii | 0.95 | 2.46 | 3.395 (4) | 167 |
Symmetry codes: (i) x−1/2, y, −z+1/2; (ii) x+1/2, −y+3/2, −z+1. |
Funding information
This research was supported by the Central Research Fund (CRF) of the University of the Free State for 2018.
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