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Crystalline 2-bromo-2-propyl mesityl sulfone (α-bromo­iso­propyl mesityl sulfone), C12H17BrO2S, exhibits significant rotational disorder of its α-bromo­iso­propyl group, although it is freely rotating in solution, as demonstrated by NMR.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801006687/om6022sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801006687/om6022Isup2.hkl
Contains datablock I

CCDC reference: 165666

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.009 Å
  • Disorder in main residue
  • R factor = 0.055
  • wR factor = 0.169
  • Data-to-parameter ratio = 14.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
PLAT_301 Alert C Main Residue Disorder ........................ 16.00 Perc. General Notes
FORMU_01 There is a discrepancy between the atom counts in the _chemical_formula_sum and the formula from the _atom_site* data. Atom count from _chemical_formula_sum:C12 H17 Br1 O2 S1 Atom count from the _atom_site data: C12.002 H17.00600 Br0.983 O2 S1 CELLZ_01 From the CIF: _cell_formula_units_Z 2 From the CIF: _chemical_formula_sum C12 H17 Br1 O2 S1 TEST: Compare cell contents of formula and atom_site data atom Z*formula cif sites diff C 24.00 24.00 0.00 H 34.00 34.01 -0.01 Br 2.00 1.97 0.03 O 4.00 4.00 0.00 S 2.00 2.00 0.00 Difference between formula and atom_site contents detected. ALERT: check formula stoichiometry or atom site occupancies.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

Unlike related isopropyl sulfones, 2-propyl mesityl sulfone could not be α-brominated with CBrCl3 in powdered KOH–tert-BuOH, but was successfully brominated by treatment with nBuLi followed by Br2 (Chan-Yu-King, 1986), to provide 2-bromo-2-propyl mesityl sulfone, (I). In a study undertaken to determine why the initial synthetic attempt was unsuccessful (Meyers et al., 1998), (I) was prepared again and its stereochemistry examined by X-ray analysis. The X-ray structure of (I) is shown with atom numbering in Fig. 1.

A salient feature of the X-ray structure resides with the significant rotational disorder of the α-bromoisopropyl group, also shown in Fig. 1. Restrained site-occupancy refinement of the six disordered sites produced the following site-occupancy values: Br1 = 0.327 (3), C11 = 0.655 (10), Br2 = 0.551 (4), C12 = 0.437 (11), Br3 = 0.105 (4), and C13 = 0.910 (11). This disorder may be associated with the small intra- and intermolecular non-bonding distances. For example, the intramolecular distances O1···C8 and O2···C7 are 0.45 and 0.42 Å, respectively, less than the sum of their van der Waals radii, while C2···C12, C6···C13, C7···C13 and C8···C12 are larger by only 0.12, 0.18, 0.10 and 0.18 Å, respectively, and the intermolecular distances O2···C7 and O2···C9 are larger by only 0.18 and 0.17 Å, respectively. However, the NMR (CDCl3) spectrum of (I) exhibits one sharp singlet (6H) for the isopropyl methyl groups.

Experimental top

2-Bromo-2-propyl mesityl sulfone, (I), was prepared by treating a tetrahydrofuran solution of mesityl 2-propyl sulfone (Hua, 1979) with nBuLi followed by the addition of Br2 in hexane, as reported by Chan-Yu-King (1986) and Meyers et al. (1998), affording crystals (from hexanes) (m.p. 361–362 K). The m.p. and X-ray analysis of these crystals were identical to those obtained with the crystals from an acetone solution which evaporated leaving an oil which slowly crystallized on standing.

Refinement top

During refinement the sum of the site-occupancy factors for the disordered Br and C sites were restrained to values of 1.0 and 2.0, respectively. Also the total site occupancy of each disordered Br/C site was restrained to 1.0. In addition, the C10—Br and C10—C distances were restrained to chemically reasonable values of 1.91 and 1.54 Å, and the C10—Br—C vectors were restrained so that they would remain relatively linear. The Br atoms were refined anisotropically, while the disordered C atoms were refined isotropically. The rotational orientation of the C7, C8, and C9 methyl groups were refined by the circular Fourier method available in SHELXL97 (Sheldrick, 1997). All H atoms were treated as riding. Although tetrahedral geometry of the α-bromoisopropyl group was not forced during the refinement, Table 1 shows that the group is relatively well behaved.

Computing details top

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1996); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: PROCESS in TEXSAN (Molecular Structure Corporation, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: LS in TEXSAN and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP in TEXSAN (Johnson, 1965); software used to prepare material for publication: TEXSAN, SHELXL97, and PLATON (Spek, 2000).

Figures top
[Figure 1] Fig. 1. The molecular structure and atom-numbering scheme for (I) with displacement ellipsoids at the 50% probability level. The apparent overlap of Br1/C11 Me, Br12/C12 Me, and Br13/C13 Me, respectively, reflects the rotational disorder of the α-bromoisopropyl group.
α-bromoisopropyl mesityl sulfone top
Crystal data top
C12H17BrO2SF(000) = 312
Mr = 305.23Dx = 1.528 Mg m3
Triclinic, P1Melting point = 361–362 K
a = 9.2865 (16) ÅMo Kα radiation, λ = 0.71069 Å
b = 9.6572 (18) ÅCell parameters from 24 reflections
c = 8.2077 (18) Åθ = 14.1–14.9°
α = 98.813 (18)°µ = 3.24 mm1
β = 92.841 (17)°T = 296 K
γ = 65.794 (12)°Irregular fragment, colorless
V = 663.4 (2) Å30.30 × 0.22 × 0.21 mm
Z = 2
Data collection top
Rigaku AFC-5S
diffractometer
1269 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.024
Graphite monochromatorθmax = 25.0°, θmin = 2.3°
ω/2θ scansh = 1111
Absorption correction: ψ scan
(North et al. 1968)
k = 1111
Tmin = 0.444, Tmax = 0.506l = 09
2526 measured reflections3 standard reflections every 100 reflections
2346 independent reflections intensity decay: 0.6%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.055H-atom parameters constrained
wR(F2) = 0.169 w = 1/[σ2(Fo2) + (0.0644P)2 + 1.0978P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
2346 reflectionsΔρmax = 0.66 e Å3
167 parametersΔρmin = 0.61 e Å3
14 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.037 (5)
Crystal data top
C12H17BrO2Sγ = 65.794 (12)°
Mr = 305.23V = 663.4 (2) Å3
Triclinic, P1Z = 2
a = 9.2865 (16) ÅMo Kα radiation
b = 9.6572 (18) ŵ = 3.24 mm1
c = 8.2077 (18) ÅT = 296 K
α = 98.813 (18)°0.30 × 0.22 × 0.21 mm
β = 92.841 (17)°
Data collection top
Rigaku AFC-5S
diffractometer
1269 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al. 1968)
Rint = 0.024
Tmin = 0.444, Tmax = 0.5063 standard reflections every 100 reflections
2526 measured reflections intensity decay: 0.6%
2346 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.05514 restraints
wR(F2) = 0.169H-atom parameters constrained
S = 1.03Δρmax = 0.66 e Å3
2346 reflectionsΔρmin = 0.61 e Å3
167 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Br10.6179 (4)0.2887 (4)0.4156 (4)0.1018 (16)0.327 (3)
Br20.4640 (3)0.0775 (2)0.3236 (3)0.0839 (8)0.551 (4)
Br30.6237 (13)0.1585 (15)0.0515 (10)0.114 (6)0.105 (4)
S10.31680 (16)0.40056 (16)0.23108 (18)0.0505 (5)
O10.2389 (5)0.4457 (5)0.3891 (5)0.0666 (12)
O20.3596 (5)0.5100 (5)0.1681 (6)0.0710 (12)
C10.2039 (6)0.3339 (6)0.0815 (6)0.0428 (12)
C20.0953 (6)0.2811 (6)0.1351 (6)0.0477 (13)
C30.0171 (7)0.2220 (6)0.0138 (8)0.0579 (16)
C40.0376 (7)0.2175 (6)0.1522 (7)0.0577 (16)
C50.1378 (7)0.2761 (7)0.1987 (7)0.0601 (16)
C60.2217 (6)0.3360 (6)0.0862 (7)0.0507 (14)
C70.3229 (8)0.4008 (9)0.1608 (8)0.076 (2)
C80.0502 (8)0.2852 (9)0.3114 (7)0.0734 (19)
C90.0490 (9)0.1501 (8)0.2793 (9)0.086 (2)
C100.4941 (5)0.2393 (4)0.2452 (4)0.0665 (17)
C110.5961 (17)0.2888 (16)0.3755 (11)0.060 (4)*0.655 (10)
C120.473 (3)0.1026 (15)0.299 (2)0.048 (7)*0.437 (11)
C130.6035 (10)0.1677 (9)0.0923 (8)0.045 (2)*0.910 (11)
H30.05220.18380.04650.070*
H50.15040.27580.31040.072*
H7a0.31020.39170.27820.115*
H7b0.43170.34470.13580.115*
H7c0.29070.50700.11560.115*
H8a0.00340.38970.36440.110*
H8b0.14280.22880.36980.110*
H8c0.02430.23960.31150.110*
H9a0.08830.21470.36360.129*
H9b0.13580.14360.22690.129*
H9c0.02210.04940.32780.129*
H11a0.53810.33060.47780.090*0.655 (10)
H11b0.62230.36520.33830.090*0.655 (10)
H11c0.69120.20130.39140.090*0.655 (10)
H12a0.41400.06640.21800.071*0.437 (11)
H12b0.41800.13470.40330.071*0.437 (11)
H12c0.57520.02140.31010.071*0.437 (11)
H13a0.54740.13710.00270.067*0.910 (11)
H13b0.69390.07960.11730.067*0.910 (11)
H13c0.63740.24180.06170.067*0.910 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0659 (18)0.124 (3)0.085 (2)0.0254 (15)0.0363 (16)0.0228 (16)
Br20.0893 (13)0.0624 (10)0.0941 (13)0.0200 (9)0.0128 (9)0.0297 (9)
Br30.075 (7)0.158 (10)0.071 (7)0.019 (6)0.018 (5)0.017 (6)
S10.0408 (8)0.0494 (9)0.0530 (9)0.0145 (6)0.0024 (6)0.0042 (6)
O10.058 (2)0.078 (3)0.050 (2)0.022 (2)0.005 (2)0.017 (2)
O20.065 (3)0.057 (2)0.097 (3)0.033 (2)0.006 (2)0.009 (2)
C10.037 (3)0.043 (3)0.043 (3)0.011 (2)0.004 (2)0.005 (2)
C20.043 (3)0.056 (3)0.043 (3)0.019 (3)0.002 (2)0.007 (2)
C30.048 (3)0.060 (4)0.071 (4)0.027 (3)0.006 (3)0.010 (3)
C40.051 (3)0.048 (3)0.057 (4)0.008 (3)0.011 (3)0.004 (3)
C50.061 (4)0.066 (4)0.038 (3)0.012 (3)0.004 (3)0.004 (3)
C60.042 (3)0.055 (3)0.048 (3)0.010 (3)0.004 (2)0.013 (3)
C70.076 (5)0.100 (5)0.064 (4)0.041 (4)0.001 (3)0.027 (4)
C80.074 (4)0.106 (5)0.053 (4)0.049 (4)0.008 (3)0.008 (4)
C90.088 (5)0.071 (5)0.080 (5)0.025 (4)0.030 (4)0.011 (4)
C100.053 (4)0.072 (4)0.060 (4)0.014 (3)0.002 (3)0.001 (3)
Geometric parameters (Å, º) top
Br1—C101.895 (2)C3—H30.9300
Br2—C101.903 (2)C11—H11a0.9600
Br3—C101.904 (2)C11—H11b0.9600
C11—C101.543 (2)C11—H11c0.9600
C12—C101.541 (2)C12—H12a0.9600
C13—C101.539 (2)C12—H12b0.9600
S1—O11.434 (4)C12—H12c0.9600
S1—O21.440 (4)C13—H13a0.9600
S1—C101.756 (5)C13—H13b0.9600
S1—C11.790 (5)C13—H13c0.9600
C1—C61.399 (7)C7—H7a0.9600
C1—C21.416 (7)C7—H7b0.9600
C2—C31.391 (7)C7—H7c0.9600
C3—C41.377 (8)C8—H8a0.9600
C4—C51.365 (8)C8—H8b0.9600
C5—C61.389 (8)C8—H8c0.9600
C2—C81.516 (8)C9—H9a0.9600
C4—C91.516 (8)C9—H9b0.9600
C6—C71.518 (8)C9—H9c0.9600
C5—H50.9300
Br1—C10—C12102.9 (9)C2—C3—H3118.5
Br1—C10—C13106.0 (5)C10—C11—H11a109.5
Br1—C10—S1109.4 (2)C10—C11—H11b109.5
C13—C10—C12104.0 (7)C10—C11—H11c109.5
C12—C10—S1114.3 (10)C10—C12—H12a109.5
C13—C10—S1118.7 (4)C10—C12—H12b109.5
Br2—C10—C11105.6 (4)C10—C12—H12c109.5
Br2—C10—C13107.2 (4)C10—C13—H13a109.5
Br2—C10—S1112.9 (2)C10—C13—H13b109.5
C13—C10—C11103.9 (7)C10—C13—H13c109.5
C11—C10—S1107.4 (6)H11a—C11—H11b109.5
Br3—C10—C11104.7 (8)H11a—C11—H11c109.5
Br3—C10—C12106.0 (8)H11b—C11—H11c109.5
Br3—C10—S1116.2 (4)H12a—C12—H12b109.5
C12—C10—C11107.5 (10)H12a—C12—H12c109.5
O1—S1—O2117.7 (3)H12b—C12—H12c109.5
O1—S1—C10107.7 (2)H13a—C13—H13b109.5
O2—S1—C10105.9 (2)H13a—C13—H13c109.5
O1—S1—C1110.0 (2)H13b—C13—H13c109.5
O2—S1—C1109.9 (3)C6—C7—H7a109.5
C10—S1—C1104.89 (19)C6—C7—H7b109.5
C6—C1—C2120.6 (5)C6—C7—H7c109.5
C6—C1—S1120.2 (4)H7a—C7—H7b109.5
C2—C1—S1119.3 (4)H7a—C7—H7c109.5
C3—C2—C1117.2 (5)H7b—C7—H7c109.5
C3—C2—C8115.5 (5)C2—C8—H8a109.5
C1—C2—C8127.3 (5)C2—C8—H8b109.5
C4—C3—C2123.1 (6)C2—C8—H8c109.5
C5—C4—C3118.0 (5)H8a—C8—H8b109.5
C5—C4—C9121.1 (6)H8a—C8—H8c109.5
C3—C4—C9120.9 (7)H8b—C8—H8c109.5
C4—C5—C6122.8 (5)C4—C9—H9a109.5
C5—C6—C1118.2 (5)C4—C9—H9b109.5
C5—C6—C7115.2 (5)C4—C9—H9c109.5
C1—C6—C7126.5 (5)H9a—C9—H9b109.5
C4—C5—H5118.6H9a—C9—H9c109.5
C6—C5—H5118.6H9b—C9—H9c109.5
C4—C3—H3118.5
O1—S1—C1—C6157.0 (4)C2—C1—C6—C7174.8 (5)
O2—S1—C1—C625.9 (5)S1—C1—C6—C74.4 (8)
C10—S1—C1—C687.5 (4)O1—S1—C10—C13179.1 (5)
O1—S1—C1—C222.3 (5)O2—S1—C10—C1352.4 (5)
O2—S1—C1—C2153.3 (4)C1—S1—C10—C1363.7 (5)
C10—S1—C1—C293.3 (4)O1—S1—C10—C1257.4 (8)
C6—C1—C2—C34.4 (8)O2—S1—C10—C12175.9 (8)
S1—C1—C2—C3176.3 (4)C1—S1—C10—C1259.7 (8)
C6—C1—C2—C8173.7 (6)O1—S1—C10—C1161.8 (5)
S1—C1—C2—C85.5 (8)O2—S1—C10—C1164.9 (5)
C1—C2—C3—C41.9 (8)C1—S1—C10—C11178.9 (5)
C8—C2—C3—C4176.4 (5)O1—S1—C10—Br157.4 (3)
C2—C3—C4—C51.0 (9)O2—S1—C10—Br169.3 (3)
C2—C3—C4—C9179.2 (5)C1—S1—C10—Br1174.5 (3)
C3—C4—C5—C61.6 (9)O1—S1—C10—Br254.2 (3)
C9—C4—C5—C6178.7 (5)O2—S1—C10—Br2179.1 (2)
C4—C5—C6—C10.9 (8)C1—S1—C10—Br262.9 (3)
C4—C5—C6—C7178.0 (5)O1—S1—C10—Br3178.6 (6)
C2—C1—C6—C54.0 (8)O2—S1—C10—Br351.9 (6)
S1—C1—C6—C5176.8 (4)C1—S1—C10—Br364.2 (6)

Experimental details

Crystal data
Chemical formulaC12H17BrO2S
Mr305.23
Crystal system, space groupTriclinic, P1
Temperature (K)296
a, b, c (Å)9.2865 (16), 9.6572 (18), 8.2077 (18)
α, β, γ (°)98.813 (18), 92.841 (17), 65.794 (12)
V3)663.4 (2)
Z2
Radiation typeMo Kα
µ (mm1)3.24
Crystal size (mm)0.30 × 0.22 × 0.21
Data collection
DiffractometerRigaku AFC-5S
diffractometer
Absorption correctionψ scan
(North et al. 1968)
Tmin, Tmax0.444, 0.506
No. of measured, independent and
observed [I > 2σ(I)] reflections
2526, 2346, 1269
Rint0.024
(sin θ/λ)max1)0.596
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.055, 0.169, 1.03
No. of reflections2346
No. of parameters167
No. of restraints14
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.66, 0.61

Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1996), MSC/AFC Diffractometer Control Software, PROCESS in TEXSAN (Molecular Structure Corporation, 1997), SHELXS97 (Sheldrick, 1990), LS in TEXSAN and SHELXL97 (Sheldrick, 1997), ORTEP in TEXSAN (Johnson, 1965), TEXSAN, SHELXL97, and PLATON (Spek, 2000).

Selected geometric parameters (Å, º) top
Br1—C101.895 (2)C12—C101.541 (2)
Br2—C101.903 (2)C13—C101.539 (2)
Br3—C101.904 (2)S1—C101.756 (5)
C11—C101.543 (2)
Br1—C10—C12102.9 (9)Br2—C10—S1112.9 (2)
Br1—C10—C13106.0 (5)C13—C10—C11103.9 (7)
Br1—C10—S1109.4 (2)C11—C10—S1107.4 (6)
C13—C10—C12104.0 (7)Br3—C10—C11104.7 (8)
C12—C10—S1114.3 (10)Br3—C10—C12106.0 (8)
C13—C10—S1118.7 (4)Br3—C10—S1116.2 (4)
Br2—C10—C11105.6 (4)C12—C10—C11107.5 (10)
Br2—C10—C13107.2 (4)
 

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