Crystal structure and Hirshfeld surface analysis of 4-bromo-6-phenyl-6,7-di­hydro-5H-furo[2,3-f]isoindol-5-one

Alekseeva, K.A.; Grigoriev, M.S.; Kolesnik, I.A.; Murshudlu, N.A.; Hasanov, K.I.; Nazarova, R.Z.; Akkurt, M.; Manahelohe, G.M.

doi:10.1107/S2056989025007170

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ISSN: 2056-9890

Volume 81| Part 9| September 2025| Pages 844-848

https://doi.org/10.1107/S2056989025007170

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Crystal structure and Hirshfeld surface analysis of 4-bromo-6-phenyl-6,7-dihydro-5H-furo[2,3-f]isoindol-5-one

Kseniia A. Alekseeva,^a Mikhail S. Grigoriev,^b Irina A. Kolesnik,^c Narmin A. Murshudlu,^d Khudayar I. Hasanov,^e Roya Z. Nazarova,^f Mehmet Akkurt ^g and Gizachew Mulugeta Manahelohe ^h ^*

^aRUDN University, 6 Miklukho-Maklaya St., Moscow 117198, Russian Federation, ^bFrumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky prosp. 31, bld. 4, 119071, Moscow, Russian Federation, ^cInstitute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 220072 Minsk, Belarus, ^dDepartment of Chemistry, Faculty of Natural Sciences, Sumgait State University, Baku Str. 1, AZ 5008, Sumgait, Azerbaijan, ^eAzerbaijan Medical University, Scientific Research Centre (SRC), A. Kasumzade St. 14, AZ 1022, Baku, Azerbaijan, ^fBaku Engineering University, Khirdalan, Hasan Aliyev str. 120, AZ0101, Absheron, Azerbaijan, ^gDepartment of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Türkiye, and ^hDepartment of Chemistry, University of Gondar, PO Box 196, Gondar, Ethiopia
^*Correspondence e-mail: [email protected]

Edited by B. Therrien, University of Neuchâtel, Switzerland (Received 30 July 2025; accepted 12 August 2025; online 15 August 2025)

The title molecule, C₁₆H₁₀BrNO₂, is essentially planar (r.m.s. deviation = 0.004 Å). In the crystal, molecules are linked by C—H⋯O and C—H⋯Br hydrogen bonds, forming ribbons along the b-axis direction. Furthermore, π-π interactions cause the molecules to form ribbons along the [1 0 $[\overline{10}]$ ] and [1 0 10] directions [centroid-to-centroid distances = 3.703 (3), 3.734 (3), 3.703 (3), and 3.734 (3) Å]. According to a Hirshfeld surface analysis, H⋯H (33.8%), O⋯H/H⋯O (15.1%), C⋯H/H⋯C (14.6%), Br⋯H/H⋯Br (13.8%), and C⋯C (11.9%) interactions are the main contributors to the crystal packing.

Keywords: crystal structure; isoindole; furo[2,3-f]isoindole; IMDAV reaction; Diels–Alder reaction; Hirshfeld surface analysis.

CCDC reference: 2479912

1. Chemical context

Isoindoles and their partially hydrogenated and/or condensed derivatives are widely occurring heterocycles in nature. This scaffold has significant applications in diverse fields, including medicine, photoactive materials, coordination chemistry, and fine organic synthesis. Their unique structural features allow for the creation of derivatives that exhibit a wide range of biological activities. Consequently, developing novel synthetic methods to overcome existing challenges, as well as reactions that leverage isoindoles to access functionally valuable compounds, has attracted considerable attention (for recent reviews, see: Speck & Magauer, 2013 ; Weintraub & Wang, 2023 ; Ou-Ichen et al., 2024 ).

Over the past decade, our group has explored the construction of fused isoindoles via the intramolecular Diels–Alder reaction in vinylarenes (the IMDAV reaction) (Zaytsev et al., 2021 , 2023 and a review, Krishna et al., 2022 ) and expanded its synthetic utility through the development of multicomponent one-pot cascade transformations (Voronov et al., 2018 ; Alekseeva et al., 2023 , 2024 ). In a recent study (Alekseeva et al., 2020 ), it was demonstrated that 3-(2-furyl)allylamines and bromomaleic anhydride react via an IMDAV reaction followed by dehydrobromination. Furthermore, in situ-generated HBr was found to induce an aromaticity transfer from the furan ring to the cyclohexane moiety. Based on this observation, we aimed to investigate whether entirely dehydrogenated fused isoindole could be synthesized directly from 3-arylallylamine and halogen-substituted maleic anhydride. Given that the IMDAV reaction between 3-(2-furyl)allylamines and maleic anhydride yields 5-oxo-4a,5,6,7,7a,8-hexahydro-4H-furo[2,3-f]isoindole-4-carboxylic acids (Apponyi et al., 2002 ; Deng et al., 2019 ), we hypothesized that employing dibromomaleic anhydride would facilitate the formation of two carbon–carbon double bonds through successive dehydrobromination reactions.

Contrary to our expectations, the reaction between N-[(2E)-3-(furan-2-yl)prop-2-en-1-yl]aniline (2) and dibromomaleic anhydride was accompanied by simultaneous dehydrobromination and decarboxylation. The resulting product (3) displayed limited solubility in common deuterated solvents. For its characterization by NMR, compound 3 was dissolved in DMSO-d₆ and heated to 353 K to obtain a clear solution. Surprisingly, NMR analysis indicated that DMSO favours oxidation of 3 to yield 4-bromo-6-phenyl-6,7-dihydro-5H-furo[2,3-f]isoindol-5-one (1) (Fig. 1). This aromatization reaction was subsequently confirmed using non-deuterated DMSO.

Figure 1
Synthesis of 4-bromo-6-phenyl-6,7-dihydro-5H-furo[2,3-f]isoindol-5-one.

2. Structural commentary

The conformation of the molecule is stabilized by an intramolecular C—H⋯O hydrogen bond (Table 1, Fig. 2) that forms an S(6) motif (Bernstein et al., 1995 ). Thus, the molecule is planar except for some hydrogen atoms. The distances of the furthest atoms from the least squares plane of the molecule are −0.153 (4), 0.141 (4), −0.097 (4), and 0.090 (5) Å for atoms C15, C12, C16, and C13, respectively. The C5—N6—C11—C12 and C7—N6—C11—C16 torsion angles are 10.9 (6) and 5.7 (5)°, respectively. The geometric parameters of the title compound are normal and consistent with those of related compounds listed in the Database survey (Section 4).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7A⋯O2ⁱ	0.99	2.51	3.463 (5)	162
C8—H8A⋯O2ⁱⁱ	0.95	2.49	3.348 (5)	149
C12—H12A⋯O2	0.95	2.27	2.894 (6)	122
C16—H16A⋯Br1ⁱⁱ	0.95	2.97	3.864 (4)	157
Symmetry codes: (i) $[-x+2, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Figure 2
The title molecules showing the atom-labelling scheme with displacement ellipsoids drawn at the 50% probability level.

3. Supramolecular features

In the crystal, molecules are linked by C—H⋯O and C—H⋯Br hydrogen bonds, forming ribbons along the b-axis direction (Table 1, Figs. 3 and 4). The molecules are further linked by π–π interactions [Cg1⋯Cg3ⁱ = 3.703 (3) Å, slippage = 1.236 Å; Cg2⋯Cg3ⁱⁱ = 3.734 (3) Å, slippage = 1.243 Å; Cg3⋯Cg1^b = 3.703 (3) Å, slippage = 1.227 Å; symmetry codes: (i) −1 + x, y, z; (ii) 1 + x, y, z; where Cg1, Cg2 and Cg3 are the centroids of the O1/C2/C3/C3A/C8A, N6/C5/C4A/C7A/C7 and C3A/C4/C4A/C7A/C8/C8A rings, respectively], thus forming ribbons along the [1 0 $[\overline{10}]$ ] and [1 0 10] directions (Table 1, Fig. 5). C—H⋯π interactions were not observed.

Figure 3
Partial packing of the title compound, viewed down the a-axis direction, showing C—H⋯O and C—H⋯Br hydrogen bonds as dashed lines. H atoms not involved in these interactions have been omitted for clarity.

Figure 4
View of the C—H⋯O and C—H⋯Br interactions down the b-axis direction.

Figure 5
A partial view down the b-axis direction showing the π–π interactions (dashed lines).

Using CrystalExplorer 17.5 (Spackman et al., 2021 ), a Hirshfeld surface analysis was performed to visualize the intermolecular interactions (Tables 1 and 2). The red and blue areas in the Hirshfeld surface plotted over the d_norm (Fig. 6) show contacts that are shorter or longer, respectively, than the van der Waals radii, while the white surface shows contacts with distances equal to the sum of the van der Waals radii (Venkatesan et al., 2016 ). Significant π–π interactions are shown by the Hirshfeld surface's shape-index (Fig. 7). Fig. 8 shows the overall two-dimensional fingerprint plot, and Fig. 8b–f shows those delineated into H⋯H (33.8%), O⋯H/H⋯O (15.1%), C⋯H/H⋯C (14.6%), Br⋯H/H⋯Br (13.8%) and C⋯C (11.9%) interactions. Smaller contributions are made by C⋯O/O⋯C (4.9%), C⋯Br/Br⋯C (2.6%), N⋯H/H⋯N (1.8%), C⋯N/N⋯C (0.8%), Br⋯Br (0.6%) and O⋯O (0.1%) contacts.

Table 2
Short interatomic contacts (Å)

Contact	distance	Symmetry operation
O2⋯H7A	2.51	2 − x, − $[{1\over 2}]$ + y, $[{3\over 2}]$ − z
O2⋯H8A	2.49	1 − x, − $[{1\over 2}]$ + y, $[{3\over 2}]$ − z
H7B⋯C11	2.85	−1 + x, y, z
H2A⋯H15A	2.58	$[{3\over 2}]$ − x, 1 − y, − $[{1\over 2}]$ + z
H3A⋯H3A	2.51	− $[{1\over 2}]$ + x, $[{1\over 2}]$ − y, 1 − z
C14⋯H14A	2.91	− $[{1\over 2}]$ + x, $[{1\over 2}]$ − y, 2 − z
H2A⋯H15A	2.54	$[{1\over 2}]$ − x, 1 − y, − $[{1\over 2}]$ + z

Figure 6
View of the three-dimensional Hirshfeld surface of the title compound plotted over d_norm.

Figure 7
Hirshfeld surface of the title compound plotted over shape-index.

Figure 8
Two-dimensional fingerprint plots, showing (a) all interactions, and delineated into (b) H⋯H, (c) O⋯H/H⋯O, (d) C⋯H/H⋯C, (e) C⋯Br/Br⋯C and (f) C⋯C interactions [d_e and d_i represent the distances from a point on the Hirshfeld surface to the nearest atoms outside (external) and inside (internal) the surface, respectively].

4. Database survey

A search of the Cambridge Structural Database (CSD, Version 6.00, last update April 2025; Groom et al., 2016 ) gave nine hits including the 4-bromo-6-phenyl-6,7-dihydro-5H-furo[2,3-f]isoindol-5-one unit, five of which were closely related to the title compound, viz. CSD refcodes HEMVEE (He et al., 2022 ), JOGYIP (Zhou et al., 2014 ), LESXIS (Horak et al., 2013 ), OJIPUV (Zaytsev et al., 2021) and QADZIH (Zubkov et al., 2016 ).

π–π and C—H⋯π interactions are observed in the structure of HEMVEE. In JOGYIP, weak C—H⋯O interactions lead to the formation of a three-dimensional network and C—H⋯π interactions are also observed. In LESXIS, O—H⋯O hydrogen bonds between the carboxylic and carbonyl groups link alternate independent molecules into chains propagating along the b-axis direction. The crystal packing also features weak C—H⋯π interactions. In OJIPUV, molecules are connected by C—H⋯O hydrogen bonds, C—H⋯π interactions and π–π stacking interactions, forming a three-dimensional network. In QADZIH, pairs of O—H⋯O hydrogen bond form dimers with an R₂²(8) motif. C—H⋯O hydrogen bonds, π–π and C—H⋯π interactions were also observed, forming a three-dimensional network.

5. Synthesis and crystallization

N-[(2E)-3-(Furan-2-yl)prop-2-en-1-yl]aniline (1.26 mmol) (2) was dissolved in dry CH₂Cl₂ (10 mL) and cooled to 251 K. Dibromomaleic anhydride (0.32 g, 1.26 mmol) was added, and the mixture was kept at 269 K for 2 d. The resulting precipitate was filtered, dissolved in dry DMSO (10 mL), and stirred at 353 K for 10 h. The mixture was poured into water (50 mL), the resulting precipitate was filtered off, and washed with water (3 × 3 mL). The product was dried in air to constant weight to afford compound 1 as a light-yellow solid (216.6 mg, 0.66 mmol, 52%), m.p. 481–482 K. A single crystal suitable for X-ray analysis was obtained from DMSO-d₆ upon heating to 353 K and slow cooling to r.t.

¹H NMR (700.2 MHz, DMSO-d₆, 333 K) (J, Hz): δ 8.21 (br. d, J = 2.2, 1H, H-2-furyl), 7.90–7.89 (m, 3H, H-ortho-Ph, H-8), 7.45 (dd, J = 7.6, 2H, H-meta-Ph), 7.20 (dd, J = 7.6, 1H, H-para-Ph), 7.11–7.09 (m, 1H, H-3-furyl), 5.03 (s, 2H, H-7) ppm. ¹³C{¹H} NMR (176.1 MHz, DMSO-d₆, 333 K): δ 164.3, 155.7, 148.1, 139.7, 139.2, 129.8, 128.7 (2C), 124.3, 124.0, 119.5 (2C), 110.0, 106.7, 105.7, 48.8 ppm. IR (KBr), ν (cm⁻¹): 3072, 1686, 1598, 1503, 1452, 1392, 1295, 1266, 1179, 1136, 1035, 878, 754, 690, 606. MS (ESI) m/z: [M]⁺ 327 (Br⁷⁹), 329 (Br⁸¹).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. All hydrogen atoms were positioned geometrically and refined using a riding model, with C—H = 0.95 and 0.99 Å, and with U_iso(H) = 1.2U_eq(C). Five reflections (0 1 1, 0 0 2, 0 1 3, 0 1 2 and 0 2 0) affected by the incident beam-stop, as well as nine reflections showing poor agreement between observed and calculated intensities (3 0 26, 0 13 9, 3 0 25, 4 12 5, −3 8 22, 0 11 8, 4 4 18, 0 5 32 and 0 2 26), were omitted in the final cycles of refinement. The remaining positive and negative residual electron densities are both located near the bromine atom (at 1.11 and 0.77 Å, respectively).

Table 3
Experimental details

Crystal data
Chemical formula	C₁₆H₁₀BrNO₂
M_r	328.16
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	100
a, b, c (Å)	4.0229 (5), 12.7225 (16), 24.240 (3)
V (Å³)	1240.6 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.31
Crystal size (mm)	0.32 × 0.30 × 0.04

Data collection
Diffractometer	Bruker Kappa APEXII area-detector
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.417, 0.879
No. of measured, independent and observed [I > 2σ(I)] reflections	18771, 3594, 2973
R_int	0.077
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.040, 0.078, 1.02
No. of reflections	3594
No. of parameters	181
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.62
Absolute structure	Flack x determined using 1016 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	0.022 (10)
Computer programs: APEX2 and SAINT (Bruker, 2007 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ) and PLATON (Spek, 2020 ).

Supporting information

CCDC reference: 2479912

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989025007170/tx2102sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989025007170/tx2102Isup2.hkl

checkCIF report

Computing details top

4-Bromo-6-phenyl-6,7-dihydro-5H-furo[2,3-f]isoindol-5-one top

Crystal data top

C₁₆H₁₀BrNO₂	D_x = 1.757 Mg m⁻³
M_r = 328.16	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 3489 reflections
a = 4.0229 (5) Å	θ = 3.0–25.4°
b = 12.7225 (16) Å	µ = 3.31 mm⁻¹
c = 24.240 (3) Å	T = 100 K
V = 1240.6 (3) Å³	Plate, colourless
Z = 4	0.32 × 0.30 × 0.04 mm
F(000) = 656

Data collection top

Bruker Kappa APEXII area-detector diffractometer	2973 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.077
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 30.0°, θ_min = 3.3°
T_min = 0.417, T_max = 0.879	h = −5→5
18771 measured reflections	k = −16→17
3594 independent reflections	l = −34→33

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.040	w = 1/[σ²(F_o²) + (0.0274P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.078	(Δ/σ)_max = 0.001
S = 1.02	Δρ_max = 0.52 e Å⁻³
3594 reflections	Δρ_min = −0.62 e Å⁻³
181 parameters	Absolute structure: Flack x determined using 1016 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: 0.022 (10)

Special details top

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.

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

	x	y	z	U_iso*/U_eq
C2	0.1419 (11)	0.4353 (3)	0.53657 (19)	0.0205 (10)
H2A	0.039792	0.449845	0.502063	0.025*
C3	0.2950 (10)	0.3444 (3)	0.54847 (16)	0.0200 (8)
H3A	0.320895	0.285576	0.524699	0.024*
C3A	0.4127 (10)	0.3535 (3)	0.60449 (17)	0.0167 (9)
C4	0.5804 (10)	0.2896 (3)	0.64168 (19)	0.0161 (9)
C4A	0.6479 (10)	0.3280 (3)	0.69413 (18)	0.0147 (9)
C5	0.8145 (11)	0.2779 (3)	0.74191 (17)	0.0163 (9)
C7	0.6555 (10)	0.4511 (3)	0.76800 (17)	0.0150 (9)
H7A	0.811196	0.511277	0.769853	0.018*
H7B	0.461702	0.465597	0.791989	0.018*
C7A	0.5487 (10)	0.4299 (3)	0.70951 (19)	0.0155 (9)
C8	0.3782 (11)	0.4975 (3)	0.67421 (19)	0.0188 (10)
H8A	0.311613	0.566361	0.684592	0.023*
C8A	0.3142 (10)	0.4549 (3)	0.62221 (18)	0.0170 (8)
C11	0.9486 (9)	0.3387 (3)	0.83835 (17)	0.0149 (8)
C12	1.1382 (11)	0.2504 (3)	0.8542 (2)	0.0198 (10)
H12A	1.187944	0.197127	0.827962	0.024*
C13	1.2511 (13)	0.2415 (3)	0.90762 (18)	0.0220 (9)
H13A	1.378112	0.181725	0.917973	0.026*
C14	1.1824 (11)	0.3186 (3)	0.94674 (19)	0.0215 (10)
H14A	1.259007	0.311386	0.983614	0.026*
C15	1.0007 (11)	0.4061 (3)	0.9311 (2)	0.0216 (10)
H15A	0.954266	0.459313	0.957452	0.026*
C16	0.8850 (10)	0.4174 (3)	0.87735 (19)	0.0178 (9)
H16A	0.763101	0.478337	0.867127	0.021*
Br1	0.71800 (10)	0.15364 (3)	0.61842 (2)	0.01845 (12)
N6	0.8208 (8)	0.3525 (2)	0.78384 (14)	0.0160 (7)
O1	0.1493 (8)	0.5055 (2)	0.58015 (12)	0.0221 (8)
O2	0.9264 (8)	0.1878 (2)	0.74491 (13)	0.0206 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C2	0.020 (2)	0.026 (2)	0.015 (2)	0.0007 (18)	−0.0004 (19)	−0.0008 (18)
C3	0.019 (2)	0.025 (2)	0.016 (2)	−0.004 (2)	0.0013 (18)	−0.0036 (18)
C3A	0.0174 (18)	0.016 (2)	0.017 (2)	−0.0025 (17)	0.0048 (16)	0.0012 (18)
C4	0.015 (2)	0.010 (2)	0.023 (3)	−0.0015 (15)	0.0071 (18)	−0.0017 (17)
C4A	0.0145 (19)	0.010 (2)	0.020 (2)	−0.0007 (14)	0.0036 (16)	0.0018 (15)
C5	0.018 (2)	0.0134 (18)	0.018 (2)	−0.0019 (16)	0.0033 (19)	0.0004 (16)
C7	0.017 (2)	0.0124 (19)	0.016 (2)	0.0004 (15)	0.0021 (18)	0.0000 (16)
C7A	0.016 (2)	0.012 (2)	0.019 (2)	−0.0004 (16)	0.0037 (18)	−0.0009 (17)
C8	0.017 (2)	0.015 (2)	0.024 (3)	0.0031 (16)	0.0043 (18)	−0.0005 (19)
C8A	0.0164 (19)	0.0164 (18)	0.018 (2)	0.0002 (15)	0.000 (2)	0.0032 (17)
C11	0.0139 (19)	0.014 (2)	0.017 (2)	−0.0021 (17)	0.0039 (16)	0.0023 (18)
C12	0.019 (2)	0.014 (2)	0.027 (3)	−0.0009 (16)	0.000 (2)	0.0022 (18)
C13	0.020 (2)	0.0184 (19)	0.027 (2)	−0.002 (2)	−0.001 (2)	0.0050 (17)
C14	0.022 (2)	0.023 (2)	0.020 (2)	−0.0056 (18)	0.001 (2)	0.0036 (17)
C15	0.017 (2)	0.022 (2)	0.026 (3)	−0.0022 (18)	0.005 (2)	−0.005 (2)
C16	0.0175 (19)	0.015 (2)	0.020 (2)	0.0000 (14)	0.000 (2)	−0.0019 (19)
Br1	0.02005 (19)	0.01300 (17)	0.0223 (2)	0.00054 (17)	0.0027 (2)	−0.00368 (18)
N6	0.0195 (17)	0.0117 (15)	0.0168 (17)	−0.0017 (16)	0.0024 (14)	−0.0014 (15)
O1	0.027 (2)	0.0178 (16)	0.0215 (18)	0.0016 (13)	−0.0013 (14)	0.0030 (13)
O2	0.0301 (18)	0.0098 (14)	0.0217 (19)	0.0055 (12)	−0.0003 (14)	0.0004 (12)

Geometric parameters (Å, º) top

C2—C3	1.342 (6)	C7A—C8	1.393 (6)
C2—O1	1.384 (5)	C8—C8A	1.396 (6)
C2—H2A	0.9500	C8—H8A	0.9500
C3—C3A	1.443 (5)	C8A—O1	1.376 (5)
C3—H3A	0.9500	C11—C16	1.401 (6)
C3A—C4	1.389 (6)	C11—C12	1.411 (6)
C3A—C8A	1.416 (5)	C11—N6	1.429 (5)
C4—C4A	1.389 (6)	C12—C13	1.378 (6)
C4—Br1	1.902 (4)	C12—H12A	0.9500
C4A—C7A	1.407 (5)	C13—C14	1.392 (6)
C4A—C5	1.482 (6)	C13—H13A	0.9500
C5—O2	1.233 (4)	C14—C15	1.385 (6)
C5—N6	1.391 (5)	C14—H14A	0.9500
C7—N6	1.470 (5)	C15—C16	1.390 (6)
C7—C7A	1.506 (6)	C15—H15A	0.9500
C7—H7A	0.9900	C16—H16A	0.9500
C7—H7B	0.9900

C3—C2—O1	112.5 (4)	C7A—C8—H8A	123.0
C3—C2—H2A	123.8	C8A—C8—H8A	123.0
O1—C2—H2A	123.8	O1—C8A—C8	125.2 (4)
C2—C3—C3A	106.5 (4)	O1—C8A—C3A	109.7 (4)
C2—C3—H3A	126.8	C8—C8A—C3A	125.2 (4)
C3A—C3—H3A	126.8	C16—C11—C12	119.0 (4)
C4—C3A—C8A	118.2 (4)	C16—C11—N6	118.1 (4)
C4—C3A—C3	136.3 (4)	C12—C11—N6	122.9 (4)
C8A—C3A—C3	105.5 (4)	C13—C12—C11	119.9 (4)
C4A—C4—C3A	118.9 (4)	C13—C12—H12A	120.0
C4A—C4—Br1	122.3 (3)	C11—C12—H12A	120.0
C3A—C4—Br1	118.8 (3)	C12—C13—C14	121.1 (4)
C4—C4A—C7A	120.7 (4)	C12—C13—H13A	119.4
C4—C4A—C5	130.8 (4)	C14—C13—H13A	119.4
C7A—C4A—C5	108.5 (4)	C15—C14—C13	119.0 (4)
O2—C5—N6	125.8 (4)	C15—C14—H14A	120.5
O2—C5—C4A	127.6 (4)	C13—C14—H14A	120.5
N6—C5—C4A	106.6 (3)	C14—C15—C16	121.1 (4)
N6—C7—C7A	102.8 (3)	C14—C15—H15A	119.4
N6—C7—H7A	111.2	C16—C15—H15A	119.4
C7A—C7—H7A	111.2	C15—C16—C11	119.8 (4)
N6—C7—H7B	111.2	C15—C16—H16A	120.1
C7A—C7—H7B	111.2	C11—C16—H16A	120.1
H7A—C7—H7B	109.1	C5—N6—C11	126.7 (3)
C8—C7A—C4A	123.1 (4)	C5—N6—C7	112.5 (3)
C8—C7A—C7	127.5 (4)	C11—N6—C7	120.6 (3)
C4A—C7A—C7	109.5 (4)	C8A—O1—C2	105.9 (3)
C7A—C8—C8A	113.9 (4)

O1—C2—C3—C3A	0.5 (5)	C4—C3A—C8A—O1	−179.3 (3)
C2—C3—C3A—C4	178.6 (5)	C3—C3A—C8A—O1	−0.4 (4)
C2—C3—C3A—C8A	0.0 (4)	C4—C3A—C8A—C8	1.4 (6)
C8A—C3A—C4—C4A	−0.8 (6)	C3—C3A—C8A—C8	−179.7 (4)
C3—C3A—C4—C4A	−179.3 (4)	C16—C11—C12—C13	1.5 (6)
C8A—C3A—C4—Br1	−179.5 (3)	N6—C11—C12—C13	−179.4 (4)
C3—C3A—C4—Br1	2.1 (7)	C11—C12—C13—C14	−0.2 (7)
C3A—C4—C4A—C7A	−0.1 (6)	C12—C13—C14—C15	−0.8 (7)
Br1—C4—C4A—C7A	178.6 (3)	C13—C14—C15—C16	0.5 (7)
C3A—C4—C4A—C5	178.8 (4)	C14—C15—C16—C11	0.8 (6)
Br1—C4—C4A—C5	−2.6 (6)	C12—C11—C16—C15	−1.8 (6)
C4—C4A—C5—O2	−1.2 (8)	N6—C11—C16—C15	179.0 (4)
C7A—C4A—C5—O2	177.7 (4)	O2—C5—N6—C11	−1.8 (7)
C4—C4A—C5—N6	179.0 (4)	C4A—C5—N6—C11	178.0 (3)
C7A—C4A—C5—N6	−2.1 (5)	O2—C5—N6—C7	−177.8 (4)
C4—C4A—C7A—C8	0.4 (6)	C4A—C5—N6—C7	2.0 (5)
C5—C4A—C7A—C8	−178.6 (4)	C16—C11—N6—C5	−170.0 (4)
C4—C4A—C7A—C7	−179.5 (4)	C12—C11—N6—C5	10.9 (6)
C5—C4A—C7A—C7	1.4 (5)	C16—C11—N6—C7	5.7 (5)
N6—C7—C7A—C8	179.8 (4)	C12—C11—N6—C7	−173.4 (4)
N6—C7—C7A—C4A	−0.2 (4)	C7A—C7—N6—C5	−1.2 (4)
C4A—C7A—C8—C8A	0.1 (6)	C7A—C7—N6—C11	−177.4 (3)
C7—C7A—C8—C8A	−179.9 (4)	C8—C8A—O1—C2	179.9 (4)
C7A—C8—C8A—O1	179.8 (4)	C3A—C8A—O1—C2	0.7 (4)
C7A—C8—C8A—C3A	−1.0 (6)	C3—C2—O1—C8A	−0.7 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···O2ⁱ	0.99	2.51	3.463 (5)	162
C8—H8A···O2ⁱⁱ	0.95	2.49	3.348 (5)	149
C12—H12A···O2	0.95	2.27	2.894 (6)	122
C16—H16A···Br1ⁱⁱ	0.95	2.97	3.864 (4)	157

Symmetry codes: (i) −x+2, y+1/2, −z+3/2; (ii) −x+1, y+1/2, −z+3/2.

Short interatomic contacts (Å) top

Contact	distance	Symmetry operation
O2···H7A	2.51	2 - x, -1/2 + y, 3/2 - z
O2···H8A	2.49	1 - x, -1/2 + y, 3/2 - z
H7B···C11	2.85	-1 + x, y, z
H2A···H15A	2.58	3/2 - x, 1 - y, -1/2 + z
H3A···H3A	2.51	-1/2 + x, 1/2 - y, 1 - z
C14···H14A	2.91	-1/2 + x, 1/2 - y, 2 - z
H2A···H15A	2.54	1/2 - x, 1 - y, -1/2 + z

Acknowledgements

The authors' contributions are as follows; conceptualization, MA, GMM; synthesis, KAA; X-ray analysis, MSG, IAK; founding, NAM, KIH; writing (review and editing of the manuscript) MA, KIH, RZN; supervision, MA, GMM.

Funding information

Funding for this research was provided by the Russian Science Foundation (project No. 23–43–10024) and the Belarusian Republican Foundation for Fundamental Research (project No. X23RNF-051).

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