Crystal structures of 2,6-di­bromo-4-methyl­benzo­nitrile and 2,6-di­bromo-4-methyl­phenyl isocyanide

Noland, W.E.; Shudy, J.E.; Rieger, J.L.; Tu, Z.H.; Tritch, K.J.

doi:10.1107/S2056989017016395

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Volume 73| Part 12| December 2017| Pages 1913-1916

https://doi.org/10.1107/S2056989017016395

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Crystal structures of 2,6-dibromo-4-methylbenzonitrile and 2,6-dibromo-4-methylphenyl isocyanide

Wayland E. Noland,^a ^* Jessica E. Shudy,^a Janel L. Rieger,^a Zoe H. Tu ^a and Kenneth J. Tritch ^a

^aDepartment of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, MN 55455, USA
^*Correspondence e-mail: nolan001@umn.edu

Edited by A. J. Lough, University of Toronto, Canada (Received 27 October 2017; accepted 15 November 2017; online 21 November 2017)

In the title crystals, C₈H₅Br₂N, which are isomorphous, the steric bulk of the methyl group causes neighboring molecules to become mutually inclined. This prevents the formation of planar or nearly planar sheets, which were observed in the trichloro and tribromo analogs. Instead of CN/NC⋯Br contacts, tetrameric Br⋯Br contacts are observed. These contacts form tetragonally puckered sheets parallel to (001). The CN/NC and methyl groups are grouped at the peaks and troughs. Both molecules lie across crystallographic mirror planes; thus, the methyl H atoms are disordered over two sets of sites with equal occupancy. The title nitrile is a redetermination. The refinement converged at R[F² > 2σ(F²)] = 0.020, whereas the original determination [Gleason & Britton, (1976 ). Cryst. Struct. Commun. 5, 229–232] had R = 0.112.

Keywords: crystal structure; nitrile; isocyanide; Br⋯Br contacts.

CCDC references: 1525809; 1525810

1. Chemical context

As part of an ongoing study of cyano–halo short contacts, the para-Br atom of 2,4,6-tribromobenzonitrile (van Rij & Britton, 1972 ) was replaced by a methyl group (Gleason & Britton, 1976), giving 2,6-dibromo-4-methylbenzonitrile (RCN). The methyl group was bulky enough to disrupt the planar sheet structure that was observed in the tribromo nitrile. As of the most recent update of the Cambridge Structural Database (CSD; Version 5.37, Feb 2017; Groom et al., 2016 ), RCN remains the only example of a 2,6-dihalobenzonitrile with a methyl group at the 4-position. Most of the examples with polyatomic 4-substituents are fluorinated benzonitriles, with applications including tuning the fluoride affinity of phosphoranes (Solyntjes et al., 2016 ), study of magnetostructural correlation (Thomson et al., 2012 ), and use as metal ligands (Díaz-Álvarez et al., 2006 ). The chlorinated and brominated entries are either bis(carbonitriles) [(I), Fig. 1; Britton, 1981 ; Hirshfeld, 1984 ; van Rij & Britton, 1981] or 4-carboxy analogs [(II); Britton, 2012 ; Noland et al., 2017 ]. All of these 4-substituents have stronger interactions than a methyl group, and exhibit different packing motifs than RCN. The comparison of corresponding nitriles and isocyanides is a rare opportunity to explore the subtle differences between molecules that are both isomeric and isoelectronic. In the 2,6-dihaloaryl series, there are only three prior examples in the CSD. The trichloro and tribromo pairs [(III); Pink et al., 2000 ; Britton et al., 2016 ] are polytypic, and the pentafluoro pair [(IV), Fig. 1; Bond et al., 2001 ; Lentz & Preugschat, 1993 ] is isomorphous. The question arose as to whether RCN and its isocyanide (2,6-dibromo-4-methylphenyl isocyanide, RNC) would be isomorphous, polytypic, or polymorphic. A single crystal of RNC and a redetermination of RCN are presented.

Figure 1
Contextual compounds.

2. Structural commentary

RNC and the redetermination of RCN are isomorphous with the original RCN structure (Gleason & Britton, 1976). The molecular structures of RCN (Fig. 2a) and RNC (Fig. 2b) are nearly planar. The two crystals described herein were pseudo-enantiomorphic, roughly being enantiomorphs with swapped cyano C and N atoms, hence the reflected ellipsoid orientations between RCN and RNC. For RCN, the mean deviation from the plane of best fit for the benzene ring (C1–C4) is 0.002 (3) Å. For RNC, this deviation (C11–C14) is 0.001 (2) Å. These planes are roughly parallel to (33 $[\overline{2}]$ ).

Figure 2
The molecular structures of (a) RCN and (b) RNC, with atom labeling and displacement ellipsoids at the 50% probability level. Unlabeled atoms are generated by the (− $[{1\over 2}]$ + y, $[{1\over 2}]$ + x, z) and ( $[{1\over 2}]$ − y, − $[{1\over 2}]$ + x, z) symmetry operations, respectively. For the methyl H atoms, only one of the two mirror-related disorder sites is shown.

3. Supramolecular features

The methyl group is sufficiently bulky to prevent planar ribbons or inversion dimers of the types found in the tribromo analogs. Instead, neighboring molecules of RCN and RNC adopt a mutually inclined arrangement. The inclination between best-fit planes for adjacent molecules of RCN is 38.3 (3)°, and 41.0 (2)° for RNC. This molecular arrangement prevents CN⋯Br and NC⋯Br contacts, but is probably affected by the formation of R₄⁴(4) rings of Br⋯Br contacts (Table 1). Each Br atom participates both as a donor (narrow C—Br⋯Br angle) and an acceptor (wide C—Br⋯Br angle). Each molecule participates in two such R₄⁴(4) rings, forming R₄⁴(24) rings. The result is a tetragonally puckered sheet structure parallel to (001) (Fig. 3). This is similar to the sheet structure reported for 2,6-dibromobenzonitrile (Britton et al., 2000 ), although without the methyl group, the sheets were nearly planar. As future work, we plan to find whether this packing motif changes when the Br atoms are replaced with I atoms.

Table 1
Contact geometry (Å, °)

C—Br⋯Br	C—Br	Br⋯Br	C—Br⋯Br
C2—Br2⋯Br2ⁱ	1.899 (5)	3.5575 (7)	96.8 (2)
C2—Br2⋯Br2ⁱⁱ	1.899 (5)	3.5575 (7)	176.41 (7)
C12—Br12⋯Br12ⁱ	1.895 (4)	3.575 (1)	97.8 (1)
C12—Br12⋯Br12ⁱⁱ	1.895 (4)	3.575 (1)	175.7 (1)
Symmetry codes: (i) 1 − y, x, 1 − z; (ii) y, 1 − x, 1 − z.

Figure 3
The sheet structure of RNC, viewed along [0 $[\overline{1}]$ 3]. The Br⋯Br contacts are represented as pink dotted lines.

4. Synthesis and crystallization

The synthesis of RCN and RNC is shown in Fig. 4.

Figure 4
The synthesis of RCN and RNC.

2,6-Dibromo-4-methylaniline (V) was prepared from 4-methylaniline based on the work of Olivier (1926 ).

RCN was prepared from (V) (980 mg) via the Sandmeyer cyanation procedure described by Britton et al. (2016; Fig. 4), as a tan powder (898 mg, 88%). M.p. 434–435 K (lit. 429–431 K; Gleason & Britton, 1976); R_f = 0.49 (SiO₂ in 2:1 hexane–ethyl acetate); ¹H NMR (500 MHz, CD₂Cl₂) δ 7.490 (s, 2H, H3A), 2.380 (s, 3H, H6A–C); ¹³C NMR (126 MHz, CD₂Cl₂) δ 147.1 (C4), 133.2 (C3), 126.6 (C2), 116.6 (C1 or C5), 116.1 (C5 or C1), 21.7 (C6); IR (KBr, cm⁻¹) 3062, 2231, 1582, 1451, 1197, 857, 747; MS (EI, m/z) [M]⁺ calculated for C₈H₅Br₂N 274.8763, found 274.8766.

2,6-Dibromo-4-methylformanilide (VI) was prepared from (V) (997 mg) via the formylation procedure described by Britton et al. (2016), performed at 60% scale, with dichloromethane instead of tetrahydrofuran. The filter cake was recrystallized from toluene, giving white needles (1.00 g, 91%). M.p. 505–506 K; R_f = 0.27 (SiO₂ in 2:1 hexane–ethyl acetate); ¹H NMR (500 MHz, (CD₃)₂SO; 2 conformers obs.) δ 9.993 (s, 1H; major), 9.743 (d, J = 10.9 Hz, 1H; minor), 8.270 (s, 1H; major), 8.021 (d, J = 11.1 Hz, 1H; minor), 7.623 (s, 2H; minor), 7.571 (s, 2H; major), 2.303 (s, 3H; both); ¹³C NMR (126 MHz, (CD₃)₂SO; 2 conformers obs.) δ 164.5 (1C; minor), 159.6 (1C; major), 140.9 (1C; minor), 140.7 (1C; major), 133.0 (2C; minor), 132.6 (2C; major), 131.9 (1C; minor), 131.8 (1C; major), 123.3 (2C; minor), 123.2 (2C; major), 19.8 (1C; both); IR (KBr, cm⁻¹) 3247, 2927, 1656, 1511, 1152, 1060, 840, 747, 684; MS (ESI, m/z) [M–H]⁻ calculated for C₈H₇Br₂NO 289.8822, found 289.8814.

RNC was prepared from (VI) (254 mg) via the amide dehydration procedure described by Britton et al. (2016), performed at 15% scale, as a beige powder (190 mg, 81%). M.p. 401–402 K; R_f = 0.53 (SiO₂ in 3:1 hexane–ethyl acetate); ¹H NMR (400 MHz, CD₂Cl₂) δ 7.456 (s, 2H, H13), 2.346 (s, 3H, H16A–C); ¹³C NMR (101 MHz, CD₂Cl₂) δ 172.7 (C15), 142.9 (C14), 133.2 (C13), 126.0 (C11), 120.8 (C12), 21.2 (C16); IR (KBr, cm⁻¹) 3061, 2922, 2850, 2118, 1654, 1586, 1451, 1384, 1064, 857, 748, 701; MS (EI, m/z) [M]⁺ calculated for C₈H₅Br₂N 274.8783, found 274.8784.

Crystallization: RCN and RNC crystals were grown by slow evaporation of dichloromethane solutions under ambient conditions. Crystals were collected by suction filtration when a small portion of the original solvent remained, and then they were washed with pentane.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. A direct-methods solution was calculated, followed by full-matrix least squares/difference-Fourier cycles. All H atoms were placed in calculated positions (C—H = 0.95 or 0.98 Å) and refined as riding atoms with U_iso(H) set to 1.2U_eq(C) for aryl H atoms and 1.5U_eq(C) for methyl H atoms. Because the molecules lie across mirror planes, the methyl H atoms are disordered across two sets of sites with 1:1 occupancy.

Table 2
Experimental details

	RCN	RNC
Crystal data
Chemical formula	C₈H₅Br₂N	C₈H₅Br₂N
M_r	274.95	274.95
Crystal system, space group	Tetragonal, P $[\overline{4}]$ 2₁m	Tetragonal, P $[\overline{4}]$ 2₁m
Temperature (K)	123	173
a, c (Å)	14.6731 (5), 3.9727 (1)	14.690 (5), 4.0703 (15)
V (Å³)	855.32 (6)	878.3 (7)
Z	4	4
Radiation type	Cu Kα	Mo Kα
μ (mm⁻¹)	11.46	9.16
Crystal size (mm)	0.50 × 0.07 × 0.04	0.40 × 0.14 × 0.08

Data collection
Diffractometer	Bruker Venture PHOTON-II	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996 )	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.314, 0.754	0.255, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	8444, 904, 902	10248, 1074, 1001
R_int	0.039	0.045
(sin θ/λ)_max (Å⁻¹)	0.624	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.020, 0.057, 1.27	0.023, 0.051, 1.14
No. of reflections	904	1074
No. of parameters	60	59
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.37, −0.32	0.30, −0.51
Absolute structure	Flack x determined using 348 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )	Flack x determined using 381 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013)
Absolute structure parameter	−0.02 (3)	−0.024 (13)
Computer programs: APEX2 and SAINT (Bruker, 2012 ), SHELXT2014 (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), Mercury (Macrae et al., 2008 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC references: 1525809; 1525810

Crystal structure: contains datablocks RCN, RNC. DOI: https://doi.org/10.1107/S2056989017016395/lh5859sup1.cif

Structure factors: contains datablock RCN. DOI: https://doi.org/10.1107/S2056989017016395/lh5859RCNsup2.hkl

Structure factors: contains datablock RNC. DOI: https://doi.org/10.1107/S2056989017016395/lh5859RNCsup3.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989017016395/lh5859RCNsup4.cml

Supporting information file. DOI: https://doi.org/10.1107/S2056989017016395/lh5859RNCsup5.cml

checkCIF report

Computing details top

For both structures, data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

3,5-Dibromo-4-methylbenzonitrile (RCN) top

Crystal data top

C₈H₅Br₂N	Melting point: 434 K
M_r = 274.95	Cu Kα radiation, λ = 1.54178 Å
Tetragonal, P42₁m	Cell parameters from 2980 reflections
a = 14.6731 (5) Å	θ = 4.3–74.0°
c = 3.9727 (1) Å	µ = 11.46 mm⁻¹
V = 855.32 (6) Å³	T = 123 K
Z = 4	Needle, colourless
F(000) = 520	0.50 × 0.07 × 0.04 mm
D_x = 2.135 Mg m⁻³

Data collection top

Bruker Venture PHOTON-II diffractometer	902 reflections with I > 2σ(I)
Radiation source: ImuS micro-focus	R_int = 0.039
φ and ω scans	θ_max = 74.2°, θ_min = 6.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −18→18
T_min = 0.314, T_max = 0.754	k = −17→17
8444 measured reflections	l = −4→4
904 independent reflections

Refinement top

Refinement on F²	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ²(F_o²) + 2.1952P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.020	(Δ/σ)_max = 0.001
wR(F²) = 0.057	Δρ_max = 0.37 e Å⁻³
S = 1.27	Δρ_min = −0.32 e Å⁻³
904 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
60 parameters	Extinction coefficient: 0.0055 (4)
0 restraints	Absolute structure: Flack x determined using 348 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
Hydrogen site location: inferred from neighbouring sites	Absolute structure parameter: −0.02 (3)

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	Occ. (<1)
C1	0.2722 (3)	0.7722 (3)	0.357 (2)	0.0156 (13)
C2	0.2985 (3)	0.6837 (4)	0.2695 (13)	0.0177 (10)
Br2	0.41762 (3)	0.64354 (3)	0.38319 (19)	0.0222 (2)
C3	0.2404 (3)	0.6240 (3)	0.1067 (15)	0.0185 (9)
H3A	0.2605	0.5645	0.0486	0.022*
C4	0.1517 (3)	0.6517 (3)	0.0283 (18)	0.0189 (15)
C5	0.3328 (4)	0.8328 (4)	0.532 (2)	0.0223 (17)
N1	0.3806 (3)	0.8806 (3)	0.676 (2)	0.0309 (17)
C6	0.0866 (3)	0.5866 (3)	−0.138 (2)	0.0212 (13)
H6A	0.0306	0.6190	−0.1991	0.032*	0.5
H6B	0.0720	0.5369	0.0175	0.032*	0.5
H6C	0.1148	0.5615	−0.3417	0.032*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0183 (18)	0.0183 (18)	0.010 (3)	−0.003 (2)	0.000 (2)	0.000 (2)
C2	0.015 (2)	0.019 (2)	0.019 (3)	0.0001 (19)	0.0034 (19)	0.0025 (19)
Br2	0.0147 (3)	0.0236 (3)	0.0282 (3)	0.00002 (17)	−0.0017 (2)	0.0042 (3)
C3	0.018 (2)	0.015 (2)	0.022 (2)	−0.0001 (17)	0.002 (3)	−0.003 (2)
C4	0.018 (2)	0.018 (2)	0.020 (4)	−0.005 (3)	0.0031 (18)	0.0031 (18)
C5	0.022 (2)	0.022 (2)	0.024 (4)	−0.002 (3)	0.000 (2)	0.000 (2)
N1	0.031 (2)	0.031 (2)	0.030 (4)	−0.009 (3)	−0.003 (2)	−0.003 (2)
C6	0.023 (2)	0.023 (2)	0.017 (3)	−0.005 (3)	0.000 (2)	0.000 (2)

Geometric parameters (Å, º) top

C1—C2ⁱ	1.399 (6)	C4—C3ⁱ	1.398 (6)
C1—C2	1.399 (6)	C4—C6	1.505 (10)
C1—C5	1.437 (10)	C5—N1	1.145 (11)
C2—C3	1.383 (8)	C6—H6A	0.9800
C2—Br2	1.899 (5)	C6—H6B	0.9800
C3—C4	1.398 (6)	C6—H6C	0.9800
C3—H3A	0.9500

C2ⁱ—C1—C2	116.8 (7)	C3ⁱ—C4—C6	120.3 (3)
C2ⁱ—C1—C5	121.6 (3)	C3—C4—C6	120.3 (3)
C2—C1—C5	121.6 (3)	N1—C5—C1	179.0 (9)
C3—C2—C1	122.3 (5)	C4—C6—H6A	109.5
C3—C2—Br2	118.8 (4)	C4—C6—H6B	109.5
C1—C2—Br2	118.9 (4)	H6A—C6—H6B	109.5
C2—C3—C4	119.6 (5)	C4—C6—H6C	109.5
C2—C3—H3A	120.2	H6A—C6—H6C	109.5
C4—C3—H3A	120.2	H6B—C6—H6C	109.5
C3ⁱ—C4—C3	119.5 (6)

C2ⁱ—C1—C2—C3	−0.5 (10)	C1—C2—C3—C4	−0.7 (9)
C5—C1—C2—C3	178.7 (7)	Br2—C2—C3—C4	178.5 (5)
C2ⁱ—C1—C2—Br2	−179.7 (4)	C2—C3—C4—C3ⁱ	1.9 (11)
C5—C1—C2—Br2	−0.5 (9)	C2—C3—C4—C6	−178.0 (6)

Symmetry code: (i) y−1/2, x+1/2, z.

2,6-Dibromo-4-methylphenyl isocyanide (RNC) top

Crystal data top

C₈H₅Br₂N	Melting point: 401 K
M_r = 274.95	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42₁m	Cell parameters from 2995 reflections
a = 14.690 (5) Å	θ = 2.8–26.9°
c = 4.0703 (15) Å	µ = 9.16 mm⁻¹
V = 878.3 (7) Å³	T = 173 K
Z = 4	Needle, colourless
F(000) = 520	0.40 × 0.14 × 0.08 mm
D_x = 2.079 Mg m⁻³

Data collection top

Bruker APEXII CCD diffractometer	1001 reflections with I > 2σ(I)
Radiation source: sealed tube	R_int = 0.045
φ and ω scans	θ_max = 27.6°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −18→19
T_min = 0.255, T_max = 0.746	k = −19→19
10248 measured reflections	l = −5→5
1074 independent reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.023	w = 1/[σ²(F_o²) + (0.0267P)² + 0.0073P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.051	(Δ/σ)_max < 0.001
S = 1.14	Δρ_max = 0.30 e Å⁻³
1074 reflections	Δρ_min = −0.51 e Å⁻³
59 parameters	Absolute structure: Flack x determined using 381 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: −0.024 (13)

Special details top

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Br12	0.64344 (3)	0.58324 (2)	0.38265 (14)	0.03268 (14)
N11	0.8281 (2)	0.6719 (2)	0.5307 (11)	0.0278 (11)
C11	0.7708 (2)	0.7292 (2)	0.3538 (15)	0.0228 (11)
C12	0.6845 (3)	0.7013 (3)	0.2671 (9)	0.0245 (8)
C13	0.6256 (2)	0.7587 (2)	0.0981 (10)	0.0243 (8)
H13A	0.5664	0.7382	0.0402	0.029*
C14	0.6535 (3)	0.8465 (3)	0.0132 (13)	0.0237 (11)
C15	0.8753 (3)	0.6247 (3)	0.6829 (18)	0.0474 (18)
C16	0.5894 (3)	0.9106 (3)	−0.1624 (14)	0.0328 (12)
H16A	0.5318	0.8793	−0.2065	0.049*	0.5
H16B	0.6169	0.9300	−0.3703	0.049*	0.5
H16C	0.5781	0.9640	−0.0241	0.049*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br12	0.0337 (2)	0.02125 (19)	0.0431 (2)	−0.00062 (15)	0.0071 (2)	0.0013 (2)
N11	0.0268 (15)	0.0268 (15)	0.030 (3)	0.009 (2)	0.0005 (13)	−0.0005 (13)
C11	0.0238 (15)	0.0238 (15)	0.021 (3)	0.0067 (19)	0.0031 (16)	−0.0031 (16)
C12	0.0267 (19)	0.0202 (18)	0.027 (2)	0.0008 (16)	0.0080 (16)	−0.0028 (15)
C13	0.0214 (17)	0.0240 (17)	0.0273 (19)	0.0001 (14)	0.0017 (18)	−0.0043 (19)
C14	0.0245 (16)	0.0245 (16)	0.022 (3)	0.007 (2)	0.0038 (14)	−0.0038 (14)
C15	0.048 (2)	0.048 (2)	0.046 (5)	0.016 (3)	−0.002 (2)	0.002 (2)
C16	0.0329 (18)	0.0329 (18)	0.033 (3)	0.009 (3)	−0.0013 (18)	0.0013 (18)

Geometric parameters (Å, º) top

Br12—C12	1.896 (4)	C13—H13A	0.9500
N11—C15	1.161 (8)	C14—C13ⁱ	1.396 (4)
N11—C11	1.391 (7)	C14—C16	1.511 (7)
C11—C12	1.379 (5)	C16—H16A	0.9800
C11—C12ⁱ	1.379 (5)	C16—H16B	0.9800
C12—C13	1.389 (6)	C16—H16C	0.9800
C13—C14	1.396 (4)

C15—N11—C11	178.9 (6)	C13—C14—C13ⁱ	118.7 (5)
C12—C11—C12ⁱ	118.7 (5)	C13—C14—C16	120.6 (2)
C12—C11—N11	120.6 (3)	C13ⁱ—C14—C16	120.6 (2)
C12ⁱ—C11—N11	120.6 (3)	C14—C16—H16A	109.5
C11—C12—C13	121.3 (4)	C14—C16—H16B	109.5
C11—C12—Br12	120.0 (3)	H16A—C16—H16B	109.5
C13—C12—Br12	118.7 (3)	C14—C16—H16C	109.5
C12—C13—C14	120.0 (4)	H16A—C16—H16C	109.5
C12—C13—H13A	120.0	H16B—C16—H16C	109.5
C14—C13—H13A	120.0

C12ⁱ—C11—C12—C13	−0.5 (8)	C11—C12—C13—C14	−0.1 (6)
N11—C11—C12—C13	178.2 (4)	Br12—C12—C13—C14	179.2 (3)
C12ⁱ—C11—C12—Br12	−179.8 (3)	C12—C13—C14—C13ⁱ	0.7 (7)
N11—C11—C12—Br12	−1.1 (7)	C12—C13—C14—C16	−178.3 (4)

Symmetry code: (i) −y+3/2, −x+3/2, z.

Contact geometry (Å, °). top

C—Br···Br	C—Br	Br···Br	C—Br···Br
C2—Br2···Br2ⁱ	1.899 (5)	3.5575 (7)	96.8 (2)
C2—Br2···Br2ⁱⁱ	1.899 (5)	3.5575 (7)	176.41 (7)
C12—Br12···Br12ⁱ	1.895 (4)	3.575 (1)	97.8 (1)
C12—Br12···Br12ⁱⁱ	1.895 (4)	3.575 (1)	175.7 (1)

Symmetry codes: (i) 1 – y, x, 1 – z; (ii) y, 1 – x, 1 – z.

Acknowledgements

The authors thank Victor G. Young, Jr. (X-Ray Crystallographic Laboratory, University of Minnesota) for assistance with the crystallographic determination, the Wayland E. Noland Research Fellowship Fund at the University of Minnesota Foundation for generous financial support of this project, and Doyle Britton (deceased July 7, 2015) for providing the basis of this project. This work was taken in large part from the PhD thesis of KJT (Tritch, 2017 ).

References

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Volume 73| Part 12| December 2017| Pages 1913-1916

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research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Crystal structures of 2,6-di­bromo-4-methyl­benzo­nitrile and 2,6-di­bromo-4-methyl­phenyl isocyanide

1. Chemical context

2. Structural commentary

3. Supra­molecular features

4. Synthesis and crystallization

5. Refinement

Supporting information

Acknowledgements

References

research communications

Crystal structures of 2,6-dibromo-4-methylbenzonitrile and 2,6-dibromo-4-methylphenyl isocyanide

3. Supramolecular features