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Micro-powder X-ray diffraction patterns of two compounds, namely 3-bromo­phenylboronic acid and tris(4-bromophenyl)boroxine, were recorded with microgram quantities of sample using a recently developed method employing nylon loops with synchrotron radiation and an image-plate detector. This method, besides using small amount of samples, offers the advantage of recording the powder pattern in the shortest possible time (less than a minute). The structures of the two compounds have been solved by ab initio methods using real-space techniques (simulated annealing and/or parallel tempering) followed by Rietveld refinements with soft restraints on the bond lengths of the rigid bodies. The former compound crystallizes in the monoclinic system [a = 15.7797 (4), b = 5.3085 (2), c = 9.3757 (3) Å, β = 93.357 (3)°; space group P21/c; Z = 4; Rp = 16.060, Rwp = 10.543, RB = 4.25] with sheets of individual molecules linked through an extended hydrogen-bonding network. Tris(4-bromophenyl)boroxine, displaying molecular disorder, crystallizes in the orthorhombic system [a = 18.9289 (6), b = 21.8872 (6), c = 4.8842 (2) Å; space group Pnma; Z = 4; Rp = 13.270, Rwp = 12.083, RB = 6.06], with discrete molecules held by weak van der Waals forces in a zigzag fashion. It is believed that this is the first time that powder X-ray diffraction patterns using microgram samples have been successfully employed for the structure solution and refinement of molecules with reasonable complexity.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889805015827/aj5037sup1.cif
Contains datablocks bpba, 3BPBA, T4BPB

CCDC references: 280204; 280205

Computing details top

For both compounds, data collection: MAR; cell refinement: CRYSFIRE, CHEKCELL; data reduction: FIT-2D; program(s) used to solve structure: DASH & FOX; program(s) used to refine structure: TOPAS; molecular graphics: DIAMOND.

(3BPBA) 3-borophenylboronic acid top
Crystal data top
Br(C6H4)B(OH)2Z = 4
Mr = 200.83Dx = 1.70 Mg m3
Monoclinic, P21/csynchrotron radiation, λ = 0.619383 Å
Hall symbol: -P_2ybcµ = 35.0 mm1
a = 15.7797 (4) ÅT = 295 K
b = 5.3085 (2) ÅParticle morphology: fine_powder
c = 9.3757 (3) Åwhite
β = 93.357 (3)°near_spehrical, 0.18 × 0.18 mm
V = 784.02 (4) Å3
Data collection top
1-BM
diffractometer
Specimen mounting: Small nylon loops (Hampton Research), 20 mm thick (500 to 700 mm in diameter), mounted on magnetic bases were used for sample mounting. For efficient sample preparation a very small amount (5 to 10 mg) of the sample was made into thick paste using mineral oil under the microscope, and was then scooped at the tip of the loop. The sample was rolled with care to ensure the sample remained near spherical.
Radiation source: synchrotron, APS beamline 1-BMData collection mode: transmission
PSL Si(111) monochromatorScan method: Stationary detector
Refinement top
Rp = 0.16130 parameters
Rwp = 0.105H-atom parameters not refined
Rexp = 0.198(Δ/σ)max = 0.01
3450 data pointsBackground function: Chebychev 10th order polynomial
Profile function: pseudo-VoigtPreferred orientation correction: 4th order Spherical Harmonics
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.07920.31310.68981.000*
C10.31730.36350.52321.000*
C20.24870.31120.60491.000*
C30.17400.45090.59831.000*
C40.16930.65810.50731.000*
C50.23370.72650.41971.000*
C60.30490.57940.43071.000*
B10.39910.20700.52881.000*
O10.42790.11230.65881.000*
O20.44640.16630.41281.000*
Geometric parameters (Å, º) top
Br1—C31.913C1—B11.533
C3—C21.391B1—O11.371
C3—C41.391B1—O21.372
C2—C11.390C4—C51.392
C1—C61.444C5—C61.367
C2—C3—C4117.61O1—B1—O2118.66
C2—C3—Br1117.33O1—B1—C1117.62
C4—C3—Br1124.22O2—B1—C1123.66
C3—C2—C1123.65C3—C4—C5123.61
C2—C1—C6114.02C6—C5—C4115.58
C2—C1—B1123.64C5—C6—C1125.5
C6—C1—B1122.34
(T4BPB) Tris(4-bromophenyl)boroxine top
Crystal data top
Br(C6H4)3(BO)3Z = 4
Mr = 548.31Dx = 1.80 Mg m3
Orthorhombic, Pnmasynchrotron radiation, λ = 0.619383 Å
Hall symbol: -P_2ac_2nµ = 41.8 mm1
a = 18.9289 (6) ÅT = 295 K
b = 21.8872 (6) ÅParticle morphology: fine_powder
c = 4.8842 (2) Åwhite
V = 2023.5 (1) Å3near_spehrical, 0.16 × 0.16 mm
Data collection top
1-BM
diffractometer
Specimen mounting: Small nylon loops (Hampton Research), 20 mm thick (500 to 700 mm in diameter), mounted on magnetic bases were used for sample mounting. For efficient sample preparation a very small amount (5 to 10 mg) of the sample was made into thick paste using mineral oil under the microscope, and was then scooped at the tip of the loop. The sample was rolled with care to ensure the sample remained near spherical.
Radiation source: synchrotron, APS beamline 1-BMData collection mode: transmission
PSL Si(111) monochromatorScan method: Stationary detector
Refinement top
Rp = 0.13329 parameters
Rwp = 0.121H-atom parameters not refined
Rexp = 0.133(Δ/σ)max = 0.01
2587 data pointsBackground function: Chebychev 10th order polynomial
Profile function: pseudo-VoigtPreferred orientation correction: 4th order Spherical Harmonics
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
B20.42370.30110.43441*0.500
C30.40260.36500.53991*0.500
C40.35350.36990.75031*0.500
C50.33490.42700.84921*0.500
C60.36550.47900.73971*0.500
Br70.34010.55720.87531*0.500
C80.43350.41710.43171*0.500
C90.41470.47390.53091*0.500
B100.41930.20140.44211*0.500
C110.39340.14050.56511*0.500
C120.34390.14060.77491*0.500
C130.32070.08580.88551*0.500
C140.34680.03100.78691*0.500
Br150.31500.95600.93831*0.500
C160.41970.08560.46651*0.500
C170.39650.03100.57691*0.500
O180.47250.29620.22401*0.500
O190.46860.20130.23381*0.500
B200.50560.24800.10481*0.500
C210.56540.24510.89081*0.500
C220.59400.18830.81941*0.500
C230.64760.18520.62731*0.500
C240.67280.23780.50661*0.500
Br250.74630.23410.24311*0.500
C260.59950.29860.80581*0.500
C270.65310.29640.61361*0.500
O280.39320.25380.54061*0.500
Geometric parameters (Å, º) top
B2—O281.295C11—C121.389
B2—O181.386C12—C131.386
B2—C31.543C13—C141.385
C3—C81.386C14—C171.391
C3—C41.389C16—C171.382
C4—C51.386O18—B201.358
C5—C61.385O19—B201.391
C6—C91.386C21—C221.400
C6—Br71.898C21—C261.400
C8—C91.382C22—C231.384
B10—O281.338C23—C241.377
B10—O191.380C24—C271.434
B10—C111.543C24—Br251.897
C11—C161.386C26—C271.384
O28—B2—O18122.19C12—C11—B10120.03
O28—B2—C3118.4C13—C12—C11120.03
O18—B2—C3119.37C14—C13—C12120.03
C8—C3—C4120.03C13—C14—C17120.03
C8—C3—B2120.57C17—C16—C11119.99
C4—C3—B2119.38C16—C17—C14120.19
C5—C4—C3119.85B20—O18—B2133.29
C6—C5—C4120.02B10—O19—B20132.34
C5—C6—C9119.96O18—B20—O1998.25
C5—C6—Br7120.01C22—C21—C26119.42
C9—C6—Br7120.03C23—C22—C21119.7
C9—C8—C3119.93C24—C23—C22120.22
C8—C9—C6120.21C23—C24—C27120.07
O28—B10—O19121.11C23—C24—Br25120.58
O28—B10—C11118.86C27—C24—Br25118.35
O19—B10—C11120.02C27—C26—C21120.51
C16—C11—C12119.95C26—C27—C24118.02
C16—C11—B10120.02B2—O28—B10112.09
 

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