BY 4.0 license Open Access Published online by De Gruyter (O) October 13, 2021

The crystal structure of 3-bromopicolinic acid, C6H4BrNO2

Guang Huang ORCID logo


C6H4BrNO2, orthorhombic, Pna21 (no. 33), a = 14.3975(12) Å, b = 7.5773(7) Å, c = 12.2500(10) Å, β = 90°, V = 1336.4(2) Å3, Z = 8, Rgt(F) = 0.0281, wRref(F2) = 0.0536, T = 150(2) K.

CCDC no.: 2113913

The asymmetric unit of the title crystal structure is shown in the figure. Table 1 contains crystallographic data and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters.

Table 1:

Data collection and handling.

Crystal:Colorless block
Size:0.25 × 0.15 × 0.10 mm
Wavelength:Mo Kα radiation (0.71073 Å)
μ:6.08 mm−1
Diffractometer, scan mode:Bruker APEX-II, φ and ω
θmax, completeness:26.4°, >99%
N(hkl)measured, N(hkl)unique, Rint:15,847, 2696, 0.054
Criterion for Iobs, N(hkl)gt:Iobs > 2 σ(Iobs), 2341
Programs:Bruker [1], Olex2 [2], SHELX [3, 4]
Table 2:

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2).

Br10.22803 (4)0.52861 (7)0.81495 (6)0.03716 (14)
Br20.46236 (4)0.82636 (10)0.14898 (5)0.04430 (17)
C10.3262 (4)0.5618 (8)0.5733 (5)0.0336 (14)
C20.3808 (4)0.6122 (8)0.6736 (5)0.0307 (14)
C30.3489 (4)0.6082 (8)0.7803 (5)0.0317 (13)
C40.4073 (4)0.6555 (8)0.8646 (5)0.0349 (14)
C50.4973 (4)0.7054 (8)0.8414 (5)0.0364 (15)
C60.5243 (4)0.7069 (8)0.7339 (5)0.0357 (15)
C70.5299 (4)0.8165 (8)0.4021 (5)0.0333 (13)
C80.6007 (3)0.8671 (7)0.3169 (5)0.0308 (11)
C90.5811 (4)0.8806 (8)0.2070 (5)0.0328 (14)
C100.6498 (4)0.9304 (8)0.1339 (5)0.0372 (14)
C110.7372 (4)0.9665 (8)0.1751 (5)0.0375 (14)
C120.7519 (4)0.9514 (8)0.2861 (5)0.0384 (16)
N10.4685 (3)0.6596 (6)0.6511 (6)0.0326 (9)
N20.6860 (3)0.9025 (7)0.3558 (4)0.0325(11)
O10.2493 (3)0.6525 (6)0.5614 (4)0.0396 (10)
O20.3556 (3)0.4546 (6)0.5101 (4)0.0491 (12)
O30.5656 (3)0.7083 (6)0.4753 (3)0.0361 (10)
O40.4513 (3)0.8729 (6)0.4024 (4)0.0449 (11)

Source of material

All starting materials were used as received. For the recrystallization 2.01 g (10 mmol) 3-bromopicolinic acid was mixed with 10 mL tetrahydrofuran and 1 mL deionized water under room temperature and was stirred to form a clear solution. The solution was filtered and evaporated naturally. Several days later, colorless block crystals of the title compound were obtained, yield 82% (based on the raw 3-bromopicolinic acid).

Experimental details

The structure was solved by direct methods with the SHELXS-2018 program. All H-atoms from C and N atoms were positioned with idealized geometry and refined isotropic (Uiso(H) = 1.2Ueq(C)) using a riding model with C–H = 0.95 Å. The H-atoms from O atoms positioned using peaks from the difference Fourier map and refined isotropic with the distance of O1–H1 = 0.84 Å and O3–H3 = 0.84 Å (Uiso(H) = 1.5Ueq(O)). The distance of Br1 and O4 is 3.034 Å, which indicates a short inter HL⃛A contact between Br1 and O4, resulting an Alert level B for checkcif. But there is no reasonable hydrogen bond. There may be some intermolecular weak interaction between Br1 and O4.


Among the mono-bromide-substituted picolinic acids, including 4-, 5- and 6-bromide-substituted picolinic acids and their derivatives, only the crystal structures of 4-bromopico-linic acid and methyl 5-bromo-6-methylpicolinate have been reported [5, 6]. Some of their metal complexes [7], [8], [9], [10], [11], [12], [13], [14], [15] and organometal complexes [16], [17], [18], [19], [20], [21], [22] have been also reported elsewhere. To the best of our knowledge, the crystal structures of 3-bromide-substituted picolinic acid has not been reported. Herein we reported the crystal structure of 3-bromopicolinic acid.

The asymmetric unit is made of two 3-bromopicolinic acid molecules, which show a slightly different conformation about the C1–C2 and C7–C8 bond, respectively. All bond lengths of the title compound are comparable with the reported results [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22]. There is one dimensional chain generated by hydrogen bonds O1–H1⃛N2 and O3–H3⃛N1.

Corresponding author: Guang Huang, Sino-Portugal Belt and Road Joint Laboratory on Science of Cultural Heritage Conservation, City University of Macau, Macau, P. R. China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, P. R. China, E-mail:

  1. Author contributions: The author has accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Conflict of interest statement: The author declares no conflicts of interest regarding this article.


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Received: 2021-08-28
Published Online: 2021-10-13

© 2021 Guang Huang, published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 International License.