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2,5-Di­methyl-3,3,6,6-tetra­phenyl-1,4-dioxa-2,5-diazo­nia-3,6-di­boratacyclo­hexane, C26H28B2N2O2, occupies a crystallographic inversion centre, and contains a six-membered BONBON heterocyclic ring, with a chair conformation and dative B-N bonds of length 1.640 (1) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014866/om6050sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014866/om6050Isup2.hkl
Contains datablock I

CCDC reference: 175360

Key indicators

  • Single-crystal X-ray study
  • T = 173 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.037
  • wR factor = 0.058
  • Data-to-parameter ratio = 15.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
REFLT_03 From the CIF: _diffrn_reflns_theta_max 27.89 From the CIF: _reflns_number_total 2514 TEST2: Reflns within _diffrn_reflns_theta_max Count of symmetry unique reflns 2733 Completeness (_total/calc) 91.99% Alert C: < 95% complete PLAT_420 Alert C D-H Without Acceptor N(1) - H(1) ?
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

The BONBON heterocycle (I), a condensation product of N-methylhydroxylamine and diphenylborinic acid, is an example of substituted aminoxyboranes, the dimeric nature of which has often been postulated for aminoxy- or iminoxyboranes [references cited in Kliegel et al. (1992, 1994)]. A monocyclic BONBON ring was first established by an X-ray analysis of an oxime diarylborinate (Kliegel et al., 1994). The same ring system is also present in several polycyclic compounds, which have been analysed by X-ray crystallography (Rettig & Trotter, 1983; Amt et al., 1988; Kliegel et al., 1991, 1992). Whereas in solution (1H NMR) and gas phase (mass spectrum) of (I) the presence of the monomer Ph2BONHMe is indicated, the crystals contain exclusively the BONBON dimer (I).

The molecule of (I) contains a centrosymmetric six-membered BONBON ring system, with a chair conformation [ring dihedral angles in a B—O—N—B section being 61.7 (1), -67.6 (1) and 61.1 (1)°], similar to that in related materials [e.g. Kliegel et al. (1994)]. The methyl substituents of the N atoms are in equatorial sites. The dative B—N bond is (typically) fairly long [1.640 (1) Å]. There is no N—H···O hydrogen bond, presumably as a result of the steric influence of the bulky phenyl substituents, the shortest intermolecular non-hydrogen contacts being C1···C12 and C13 = 3.46 and 3.48 Å.

Experimental top

N-Methylhydroxylamine (0.19 g, 4 mmol) and oxybis(diphenylborane) (0.70 g, 2 mmol) were dissolved in 10 ml of ethanol and heated at boiling temperature for several minutes. Evaporation and cooling yielded 0.64 g (76%) of colorless crystals of (I) (m.p. 441–443 K). IR (KBr): 3145 cm-1 (N—H); 1H NMR (400 MHz, CDCl3/TMS), δ (p.p.m.): 1.40–1.90 (s, broad, exchangeable, 20% of 2 H), 2.78 (d, J = 6 Hz, 2 CH3), 6.33 (q, J = 6 Hz, partly exchangeable, 80% of 2 H), 7.23–7.99 (m, 10 aromatic H); EI mass spectrum (70 eV, 513 K), m/z: 422 (1%, M+), 211(51%, 1/2 M+), 165 (100%, Ph2B), 133 (28%, PhBONMe), 107 (21%), 105 (26%, PhBOH), 77 (52%, C6H5). Analysis calculated for C26H28B2N2O2: C 73.96, H 6.70, N 6.64, B 5.12; found: C 74.03, H 6.62, N 6.40, B 4.98. The compound gives a deep-blue color reaction with diphenylcarbazone in methanolic solution, indicating the presence of a diphenylboron moiety (Neu, 1960; Friese & Umland, 1978). Crystals suitable for X-ray analysis were obtained by very slow crystallization from ethanol.

Refinement top

The H1 atom was refined isotropically, while all other H atoms were refined as riding on their attached atoms.

Computing details top

Data collection: D*TREK (Molecular Structure Corporation, 1996-1998); cell refinement: D*TREK; data reduction: D*TREK; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: TEXSAN (Molecular Structure Corporation, 1992-1997); software used to prepare material for publication: TEXSAN.

Figures top
[Figure 1] Fig. 1. View of the title molecule (50% probability ellipsoids).
(I) top
Crystal data top
C26H28B2N2O2F(000) = 448
Mr = 422.14Dx = 1.225 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.7107 Å
a = 6.9184 (3) ÅCell parameters from 6804 reflections
b = 8.8703 (3) Åθ = 3.2–27.9°
c = 18.7337 (9) ŵ = 0.08 mm1
β = 95.444 (3)°T = 173 K
V = 1144.47 (8) Å3Block, colorless
Z = 20.50 × 0.30 × 0.25 mm
Data collection top
Rigaku/ADSC CCD
diffractometer
2514 independent reflections
Radiation source: X-ray tube2059 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.028
Detector resolution: 11.76 pixels mm-1θmax = 27.9°, θmin = 3.2°
area detector scansh = 87
Absorption correction: multi-scan
D*TREK (Molecular Structure Corporation, 1996-1998)
k = 1010
Tmin = 0.96, Tmax = 0.98l = 2321
9941 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: full0 constraints
R[F2 > 2σ(F2)] = 0.037H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.058Weighting scheme based on measured s.u.'s w = 1/[σ2(Fo2)]
S = 1.91(Δ/σ)max = 0.005
2362 reflectionsΔρmax = 0.32 e Å3
149 parametersΔρmin = 0.20 e Å3
Crystal data top
C26H28B2N2O2V = 1144.47 (8) Å3
Mr = 422.14Z = 2
Monoclinic, P21/nMo Kα radiation
a = 6.9184 (3) ŵ = 0.08 mm1
b = 8.8703 (3) ÅT = 173 K
c = 18.7337 (9) Å0.50 × 0.30 × 0.25 mm
β = 95.444 (3)°
Data collection top
Rigaku/ADSC CCD
diffractometer
2514 independent reflections
Absorption correction: multi-scan
D*TREK (Molecular Structure Corporation, 1996-1998)
2059 reflections with I > 3σ(I)
Tmin = 0.96, Tmax = 0.98Rint = 0.028
9941 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.058H atoms treated by a mixture of independent and constrained refinement
S = 1.91Δρmax = 0.32 e Å3
2362 reflectionsΔρmin = 0.20 e Å3
149 parameters
Special details top

Experimental. Data were collected in 0.50° oscillations with 35.0 s exposures. A sweep of data was done using ϕ oscillations from 0.0 to 190.0° at χ = -90° and a second sweep was performed using ω oscillations between -18.0 and 23.0° at χ = 90.0°. The crystal-to-detector distance was 39.80 mm. The detector swing angle was -5.0°. The absorption correction is based on a three-dimensional analysis of symmetry-equivalent data and is performed along with batch scaling in a single step.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.30565 (8)0.52581 (7)0.01485 (4)0.0189 (2)
N10.3988 (1)0.62161 (9)0.03335 (5)0.0177 (2)
C10.2742 (1)0.7565 (1)0.04507 (7)0.0288 (3)
C20.3175 (1)0.3004 (1)0.07083 (5)0.0203 (2)
C30.1584 (2)0.3628 (1)0.11227 (6)0.0317 (3)
C40.1030 (2)0.3134 (2)0.18177 (7)0.0442 (4)
C50.2011 (2)0.1980 (2)0.21108 (6)0.0462 (4)
C60.3545 (2)0.1297 (2)0.17050 (7)0.0436 (4)
C70.4121 (2)0.1815 (1)0.10167 (6)0.0315 (3)
C80.2759 (1)0.2759 (1)0.07272 (5)0.0189 (2)
C90.2614 (1)0.3455 (1)0.13907 (6)0.0257 (3)
C100.1824 (2)0.2706 (1)0.19474 (6)0.0319 (3)
C110.1167 (1)0.1238 (1)0.18547 (6)0.0309 (3)
C120.1303 (1)0.0520 (1)0.12055 (6)0.0282 (3)
C130.2089 (1)0.1277 (1)0.06504 (6)0.0228 (3)
B10.3677 (1)0.3656 (1)0.00934 (6)0.0174 (3)
H10.391 (2)0.571 (1)0.0767 (7)0.024 (3)*
H20.34390.83430.06950.035*
H30.15490.72940.07470.035*
H40.24130.79520.00130.035*
H50.08410.44350.09180.038*
H60.00690.36130.20990.053*
H70.16310.16410.26020.055*
H80.42270.04490.19030.052*
H90.52230.13290.07400.038*
H100.30780.44920.14650.031*
H110.17330.32180.24060.038*
H120.06090.07110.22460.037*
H130.08460.05200.11370.034*
H140.21740.07560.01930.027*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0149 (3)0.0155 (4)0.0266 (4)0.0017 (2)0.0038 (2)0.0032 (3)
N10.0160 (4)0.0133 (4)0.0235 (4)0.0016 (3)0.0003 (3)0.0029 (3)
C10.0203 (5)0.0174 (5)0.0475 (7)0.0057 (4)0.0025 (4)0.0067 (5)
C20.0195 (5)0.0192 (5)0.0221 (5)0.0052 (3)0.0012 (3)0.0030 (4)
C30.0328 (6)0.0234 (6)0.0361 (6)0.0036 (4)0.0120 (4)0.0027 (5)
C40.0534 (8)0.0383 (7)0.0361 (7)0.0174 (6)0.0210 (6)0.0107 (6)
C50.0634 (8)0.0556 (9)0.0192 (6)0.0326 (7)0.0020 (5)0.0022 (6)
C60.0451 (7)0.0529 (9)0.0352 (7)0.0138 (6)0.0159 (5)0.0179 (6)
C70.0275 (5)0.0368 (7)0.0307 (6)0.0006 (4)0.0055 (4)0.0080 (5)
C80.0134 (4)0.0194 (5)0.0236 (5)0.0030 (3)0.0004 (3)0.0026 (4)
C90.0253 (5)0.0263 (5)0.0247 (5)0.0019 (4)0.0007 (4)0.0003 (4)
C100.0325 (6)0.0410 (7)0.0220 (5)0.0007 (5)0.0016 (4)0.0007 (5)
C110.0258 (5)0.0379 (7)0.0294 (6)0.0023 (4)0.0042 (4)0.0151 (5)
C120.0243 (5)0.0215 (5)0.0390 (6)0.0015 (4)0.0045 (4)0.0095 (4)
C130.0212 (5)0.0180 (5)0.0295 (6)0.0036 (3)0.0035 (4)0.0017 (4)
B10.0127 (5)0.0147 (5)0.0242 (5)0.0016 (3)0.0008 (4)0.0006 (4)
Geometric parameters (Å, º) top
O1—N11.436 (1)C5—H70.98
O1—B11.491 (1)C6—C71.391 (2)
N1—C11.479 (1)C6—H80.98
N1—B1i1.640 (1)C7—H90.98
N1—H10.93 (1)C8—C91.400 (2)
C1—H20.98C8—C131.397 (1)
C1—H30.98C8—B11.609 (1)
C1—H40.98C9—C101.391 (2)
C2—C31.400 (1)C9—H100.98
C2—C71.395 (2)C10—C111.384 (2)
C2—B11.616 (1)C10—H110.98
C3—C41.393 (2)C11—C121.384 (2)
C3—H50.98C11—H120.98
C4—C51.372 (2)C12—C131.391 (1)
C4—H60.98C12—H130.98
C5—C61.385 (2)C13—H140.98
C1···C12ii3.459 (1)C1···C13ii3.483 (1)
N1—O1—B1111.78 (6)C2—C7—C6122.0 (1)
O1—N1—C1106.39 (7)C2—C7—H9119.1
O1—N1—B1i110.95 (7)C6—C7—H9119.0
O1—N1—H1105.8 (8)C9—C8—C13117.08 (9)
C1—N1—B1i122.01 (7)C9—C8—B1120.25 (9)
C1—N1—H1106.3 (8)C13—C8—B1122.68 (9)
B1i—N1—H1104.3 (7)C8—C9—C10121.4 (1)
N1—C1—H2109.4C8—C9—H10119.3
N1—C1—H3109.4C10—C9—H10119.2
N1—C1—H4109.4C9—C10—C11120.2 (1)
H2—C1—H3109.6C9—C10—H11119.9
H2—C1—H4109.5C11—C10—H11119.9
H3—C1—H4109.5C10—C11—C12119.6 (1)
C3—C2—C7116.4 (1)C10—C11—H12120.3
C3—C2—B1117.52 (9)C12—C11—H12120.1
C7—C2—B1126.01 (9)C11—C12—C13119.9 (1)
C2—C3—C4121.8 (1)C11—C12—H13120.1
C2—C3—H5119.1C13—C12—H13119.9
C4—C3—H5119.2C8—C13—C12121.8 (1)
C3—C4—C5120.4 (1)C8—C13—H14119.1
C3—C4—H6119.8C12—C13—H14119.1
C5—C4—H6119.8O1—B1—N1i101.40 (7)
C4—C5—C6119.3 (1)O1—B1—C2111.58 (8)
C4—C5—H7120.4O1—B1—C8106.50 (7)
C6—C5—H7120.4N1i—B1—C2113.50 (8)
C5—C6—C7120.1 (1)N1i—B1—C8106.21 (7)
C5—C6—H8119.8C2—B1—C8116.34 (8)
C7—C6—H8120.0
O1—N1—B1i—C2i58.7 (1)C2—B1—C8—C9161.06 (9)
O1—N1—B1i—C8i172.27 (7)C2—B1—C8—C1319.3 (1)
O1—N1—B1i—O1i61.14 (9)C3—C2—C7—C61.5 (2)
O1—B1—N1i—C1i172.29 (8)C3—C2—B1—C894.0 (1)
O1—B1—C2—C328.5 (1)C3—C4—C5—C60.8 (2)
O1—B1—C2—C7155.16 (9)C4—C3—C2—C72.8 (2)
O1—B1—C8—C936.0 (1)C4—C3—C2—B1179.5 (1)
O1—B1—C8—C13144.35 (8)C4—C5—C6—C72.1 (2)
N1—O1—B1—C259.41 (9)C6—C7—C2—B1177.9 (1)
N1—O1—B1—C8172.64 (7)C7—C2—B1—C882.4 (1)
N1—O1—B1—N1i61.73 (9)C8—C9—C10—C110.3 (2)
N1—B1i—C2i—C3i142.28 (9)C8—C13—C12—C110.1 (1)
N1—B1i—C2i—C7i41.3 (1)C9—C8—C13—C120.2 (1)
N1—B1i—C8i—C9i71.5 (1)C9—C10—C11—C120.1 (2)
N1—B1i—C8i—C13i108.14 (9)C10—C9—C8—C130.4 (1)
C1—N1—O1—B1157.63 (8)C10—C9—C8—B1179.90 (8)
C1—N1—B1i—C2i67.9 (1)C10—C11—C12—C130.3 (2)
C1—N1—B1i—C8i61.2 (1)C12—C13—C8—B1179.90 (8)
C2—C3—C4—C51.7 (2)B1—O1—N1—B1i67.60 (9)
C2—C7—C6—C51.0 (2)
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC26H28B2N2O2
Mr422.14
Crystal system, space groupMonoclinic, P21/n
Temperature (K)173
a, b, c (Å)6.9184 (3), 8.8703 (3), 18.7337 (9)
β (°) 95.444 (3)
V3)1144.47 (8)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.50 × 0.30 × 0.25
Data collection
DiffractometerRigaku/ADSC CCD
diffractometer
Absorption correctionMulti-scan
D*TREK (Molecular Structure Corporation, 1996-1998)
Tmin, Tmax0.96, 0.98
No. of measured, independent and
observed [I > 3σ(I)] reflections
9941, 2514, 2059
Rint0.028
(sin θ/λ)max1)0.658
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.058, 1.91
No. of reflections2362
No. of parameters149
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.32, 0.20

Computer programs: D*TREK (Molecular Structure Corporation, 1996-1998), D*TREK, SIR97 (Altomare et al., 1999), TEXSAN (Molecular Structure Corporation, 1992-1997), TEXSAN.

Selected geometric parameters (Å, º) top
O1—N11.436 (1)C5—C61.385 (2)
O1—B11.491 (1)C6—C71.391 (2)
N1—C11.479 (1)C8—C91.400 (2)
N1—B1i1.640 (1)C8—C131.397 (1)
C2—C31.400 (1)C8—B11.609 (1)
C2—C71.395 (2)C9—C101.391 (2)
C2—B11.616 (1)C10—C111.384 (2)
C3—C41.393 (2)C11—C121.384 (2)
C4—C51.372 (2)C12—C131.391 (1)
N1—O1—B1111.78 (6)C9—C8—B1120.25 (9)
O1—N1—C1106.39 (7)C13—C8—B1122.68 (9)
O1—N1—B1i110.95 (7)C8—C9—C10121.4 (1)
C1—N1—B1i122.01 (7)C9—C10—C11120.2 (1)
C3—C2—C7116.4 (1)C10—C11—C12119.6 (1)
C3—C2—B1117.52 (9)C11—C12—C13119.9 (1)
C7—C2—B1126.01 (9)C8—C13—C12121.8 (1)
C2—C3—C4121.8 (1)O1—B1—N1i101.40 (7)
C3—C4—C5120.4 (1)O1—B1—C2111.58 (8)
C4—C5—C6119.3 (1)O1—B1—C8106.50 (7)
C5—C6—C7120.1 (1)N1i—B1—C2113.50 (8)
C2—C7—C6122.0 (1)N1i—B1—C8106.21 (7)
C9—C8—C13117.08 (9)C2—B1—C8116.34 (8)
Symmetry code: (i) x+1, y+1, z.
 

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