3H-2,1-Benzoxaborole-1-spiro-4'-(5-oxa-3a-aza-4-borapyrene).

In the title compound, C(20)H(14)BNO(2), the B atom has a tetra-hedral geometry with two short B-O and two long B-C and B-N bonds, revealing a significant difference between C(ar)-O-B and C(alk-yl)-O-B bond distances. Inter-molecular Ar-H⋯O hydrogen bonds and strong π-π inter-actions (3.368 Å) between aromatic cores of neighbouring mol-ecules result in hexa-gonal channels along the crystallographic c axis, which are potentially accessible for small mol-ecules.

Related literature

For the general synthesis and applications of benzoboroxoles, see: Nicolaou et al. (1998 ▶, 1999 ▶); Tan et al. (2001 ▶); Benkovic et al. (2005 ▶); Baker et al. (2006 ▶); Alexander et al. (1999 ▶). For the crystal structures of benzoboroxoles, see: Tan et al. (2001 ▶); Sporzynski et al. (2005 ▶); Coghlan et al. (2005 ▶); Arcus et al. (1993 ▶); Murafuji et al. (1999 ▶); Zhdankin et al. (1999 ▶); Yamamoto et al. (2005 ▶); Gunasekera et al. (2007 ▶).

For related literature, see: Allen (2002 ▶); Prince (1982 ▶); Watkin (1994 ▶).

Experimental

Crystal data

C20H14BNO2

M = 311.13

Trigonal,

a = 33.079 (5) Å

c = 7.358 (5) Å

V = 6973 (5) Å3

Z = 18

Mo Kα radiation

μ = 0.09 mm−1

T = 295 K

0.58 × 0.12 × 0.07 mm

Data collection

Rigaku AFC-7R diffractometer

Absorption correction: ψ scan (North et al., 1968 ▶) T min = 0.96, T max = 0.99

3564 measured reflections

3564 independent reflections

1558 reflections with I > 2.0σ(I)

3 standard reflections every 150 reflections intensity decay: none

Refinement

R[F 2 > 2σ(F 2)] = 0.068

wR(F 2) = 0.093

S = 1.07

1779 reflections

218 parameters

H-atom parameters constrained

Δρmax = 0.31 e Å−3

Δρmin = −0.28 e Å−3

Data collection: AFC-7R Diffractometer Control Software (Rigaku/MSC, 1997 ▶); cell refinement: WinAFC (Rigaku/MSC, 2000 ▶); data reduction: TEXSAN (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ▶); molecular graphics: CAMERON (Watkin et al., 1996 ▶); software used to prepare material for publication: CRYSTALS.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536807066731/em2005sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807066731/em2005Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C20H14BNO2	Z = 18
Mr = 311.13	F000 = 2916
Trigonal, R3	Dx = 1.334 Mg m−3
Hall symbol: -R 3	Mo Kα radiation λ = 0.71073 Å
a = 33.079 (5) Å	Cell parameters from 25 reflections
b = 33.079 (5) Å	θ = 15–18º
c = 7.358 (5) Å	µ = 0.09 mm−1
α = 90º	T = 295 K
β = 90º	Needle, yellow
γ = 120º	0.58 × 0.12 × 0.07 mm
V = 6973 (5) Å3

Serial diffractometer	Rint = 0.000
Monochromator: graphite	θmax = 27.5º
T = 295 K	θmin = 2.9º
ω/2θ scans	h = 0→42
Absorption correction: ψ scan(North et al., 1968)	k = −36→36
Tmin = 0.96, Tmax = 0.99	l = 0→9
3564 measured reflections	3 standard reflections
3564 independent reflections	every 150 reflections
1558 reflections with I > 2.0σ(I)	intensity decay: 0.00%

Refinement on F2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.068	Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) [weight] = 1.0/[A0*T0(x) + A1*T1(x) ··· + An-1]*Tn-1(x)] where Ai are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] * [1-(deltaF/6*sigmaF)2]2 Ai are: 6.52 6.79 1.78
wR(F2) = 0.093	(Δ/σ)max = 0.0003
S = 1.07	Δρmax = 0.31 e Å−3
1779 reflections	Δρmin = −0.28 e Å−3
218 parameters	Extinction correction: Larson (1970), Equation 22
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 269 (15)

	x	y	z	Uiso*/Ueq
B1	0.60386 (17)	0.50314 (19)	0.3431 (8)	0.0461
N1	0.54645 (12)	0.47492 (12)	0.3338 (5)	0.0441
O1	0.61889 (10)	0.50681 (11)	0.1583 (4)	0.0556
O2	0.61678 (10)	0.54880 (11)	0.4258 (5)	0.0557
C1	0.62617 (15)	0.47612 (16)	0.4450 (7)	0.0470
C2	0.62919 (18)	0.46446 (19)	0.6229 (7)	0.0641
C3	0.65528 (19)	0.4431 (2)	0.6641 (8)	0.0738
C4	0.67847 (17)	0.43392 (18)	0.5313 (8)	0.0612
C5	0.67633 (15)	0.44539 (16)	0.3534 (7)	0.0536
C6	0.64948 (15)	0.46632 (15)	0.3118 (7)	0.0453
C7	0.64298 (16)	0.48142 (17)	0.1297 (7)	0.0549
C8	0.52178 (17)	0.42836 (16)	0.3387 (7)	0.0556
C9	0.47493 (17)	0.40339 (17)	0.2966 (7)	0.0615
C10	0.45304 (16)	0.42688 (17)	0.2430 (7)	0.0568
C11	0.47733 (16)	0.47560 (17)	0.2342 (7)	0.0465
C12	0.52458 (15)	0.49909 (15)	0.2852 (6)	0.0420
C13	0.45737 (18)	0.5029 (2)	0.1721 (7)	0.0611
C14	0.48327 (19)	0.5502 (2)	0.1649 (7)	0.0603
C15	0.53031 (18)	0.57485 (17)	0.2257 (7)	0.0524
C16	0.55138 (15)	0.54933 (15)	0.2865 (6)	0.0441
C17	0.5559 (2)	0.62379 (19)	0.2316 (8)	0.0699
C18	0.5997 (2)	0.64575 (19)	0.3060 (9)	0.0767
C19	0.62077 (18)	0.62144 (17)	0.3711 (8)	0.0655
C20	0.59680 (16)	0.57271 (16)	0.3584 (7)	0.0492
H11	0.6135	0.4706	0.7139	0.0862*
H12	0.6569	0.4352	0.7841	0.1024*
H13	0.6955	0.4194	0.5614	0.0794*
H14	0.6922	0.4396	0.2624	0.0612*
H15	0.5372	0.4125	0.3718	0.0623*
H16	0.4586	0.3710	0.3045	0.0698*
H17	0.4215	0.4107	0.2128	0.0625*
H71	0.6732	0.5015	0.0712	0.0750*
H72	0.6242	0.4541	0.0528	0.0750*
H131	0.4263	0.4879	0.1352	0.0773*
H141	0.4698	0.5669	0.1193	0.0818*
H171	0.5430	0.6412	0.1877	0.0923*
H181	0.6162	0.6782	0.3100	0.0853*
H191	0.6501	0.6370	0.4249	0.0712*

	U11	U22	U33	U12	U13	U23
B1	0.033 (3)	0.048 (3)	0.056 (4)	0.020 (3)	0.000 (3)	0.000 (3)
N1	0.033 (2)	0.039 (2)	0.060 (3)	0.0174 (18)	0.0013 (19)	−0.0006 (19)
O1	0.049 (2)	0.060 (2)	0.063 (2)	0.0316 (19)	0.0060 (18)	0.0093 (18)
O2	0.0365 (18)	0.046 (2)	0.083 (3)	0.0192 (16)	−0.0066 (17)	−0.0093 (18)
C1	0.034 (3)	0.048 (3)	0.057 (3)	0.019 (2)	−0.002 (2)	−0.007 (2)
C2	0.060 (3)	0.086 (4)	0.061 (4)	0.048 (3)	0.000 (3)	0.000 (3)
C3	0.077 (4)	0.105 (5)	0.063 (4)	0.062 (4)	−0.002 (3)	0.007 (3)
C4	0.053 (3)	0.072 (4)	0.071 (4)	0.041 (3)	−0.006 (3)	−0.002 (3)
C5	0.039 (3)	0.054 (3)	0.068 (4)	0.024 (3)	0.004 (3)	−0.002 (3)
C6	0.035 (3)	0.042 (3)	0.054 (3)	0.016 (2)	0.002 (2)	−0.004 (2)
C7	0.050 (3)	0.056 (3)	0.063 (4)	0.030 (3)	0.009 (3)	−0.001 (3)
C8	0.048 (3)	0.038 (3)	0.080 (4)	0.022 (2)	0.006 (3)	0.003 (3)
C9	0.047 (3)	0.041 (3)	0.084 (4)	0.012 (3)	0.004 (3)	−0.007 (3)
C10	0.034 (3)	0.055 (3)	0.069 (4)	0.013 (3)	−0.003 (3)	−0.010 (3)
C11	0.039 (3)	0.051 (3)	0.051 (3)	0.024 (2)	0.001 (2)	−0.006 (2)
C12	0.036 (3)	0.044 (3)	0.048 (3)	0.021 (2)	0.001 (2)	−0.004 (2)
C13	0.045 (3)	0.081 (4)	0.067 (4)	0.039 (3)	−0.005 (3)	−0.005 (3)
C14	0.068 (4)	0.072 (4)	0.063 (4)	0.052 (3)	0.007 (3)	0.007 (3)
C15	0.056 (3)	0.056 (3)	0.055 (3)	0.036 (3)	0.010 (3)	0.005 (3)
C16	0.040 (3)	0.040 (3)	0.055 (3)	0.021 (2)	0.006 (2)	−0.002 (2)
C17	0.079 (4)	0.054 (4)	0.093 (5)	0.045 (3)	0.023 (4)	0.015 (3)
C18	0.081 (4)	0.041 (3)	0.110 (5)	0.032 (3)	0.031 (4)	0.010 (3)
C19	0.048 (3)	0.043 (3)	0.092 (5)	0.013 (3)	0.014 (3)	−0.009 (3)
C20	0.043 (3)	0.040 (3)	0.065 (3)	0.022 (2)	0.007 (2)	−0.004 (2)

O2—C20	1.354 (5)	C3—H12	0.930
B1—O2	1.479 (6)	C4—C5	1.374 (7)
C20—C16	1.405 (6)	C4—H13	0.930
C20—C19	1.399 (6)	C5—H14	0.930
C16—C12	1.440 (6)	C8—C9	1.378 (6)
C16—C15	1.410 (6)	C8—H15	0.930
C12—N1	1.367 (5)	C9—C10	1.359 (6)
C12—C11	1.405 (6)	C9—H16	0.930
B1—N1	1.646 (6)	C10—C11	1.397 (6)
N1—C8	1.335 (5)	C10—H17	0.930
B1—O1	1.432 (6)	C11—C13	1.434 (6)
B1—C1	1.602 (7)	C13—C14	1.358 (7)
O1—C7	1.433 (5)	C13—H131	0.930
C7—C6	1.482 (6)	C14—C15	1.420 (7)
C7—H71	0.980	C14—H141	0.930
C7—H72	0.980	C15—C17	1.403 (7)
C6—C1	1.382 (6)	C17—C18	1.368 (7)
C6—C5	1.406 (6)	C17—H171	0.930
C1—C2	1.382 (6)	C18—C19	1.387 (7)
C2—C3	1.396 (7)	C18—H181	0.930
C2—H11	0.930	C19—H191	0.930
C3—C4	1.366 (7)
C20—O2—B1	118.0 (4)	C4—C3—H12	120.0
O2—C20—C16	121.1 (4)	C3—C4—C5	120.5 (5)
O2—C20—C19	119.2 (5)	C3—C4—H13	119.7
C16—C20—C19	119.6 (5)	C5—C4—H13	119.8
C20—C16—C12	120.6 (4)	C6—C5—C4	118.4 (5)
C20—C16—C15	120.2 (4)	C6—C5—H14	120.5
C12—C16—C15	119.1 (4)	C4—C5—H14	121.1
C16—C12—N1	118.2 (4)	N1—C8—C9	122.8 (5)
C16—C12—C11	120.8 (4)	N1—C8—H15	117.9
N1—C12—C11	120.9 (4)	C9—C8—H15	119.3
C12—N1—B1	118.5 (4)	C8—C9—C10	118.9 (5)
C12—N1—C8	119.0 (4)	C8—C9—H16	120.6
B1—N1—C8	121.3 (4)	C10—C9—H16	120.5
N1—B1—O2	105.0 (4)	C9—C10—C11	120.6 (4)
N1—B1—O1	105.2 (4)	C9—C10—H17	120.3
O2—B1—O1	113.1 (4)	C11—C10—H17	119.0
N1—B1—C1	115.2 (4)	C12—C11—C10	117.7 (4)
O2—B1—C1	113.5 (4)	C12—C11—C13	118.2 (5)
O1—B1—C1	104.7 (4)	C10—C11—C13	124.1 (5)
B1—O1—C7	111.2 (4)	C11—C13—C14	120.9 (5)
O1—C7—C6	106.4 (4)	C11—C13—H131	119.4
O1—C7—H71	110.0	C14—C13—H131	119.7
C6—C7—H71	110.8	C13—C14—C15	121.9 (5)
O1—C7—H72	110.0	C13—C14—H141	119.0
C6—C7—H72	110.1	C15—C14—H141	119.1
H71—C7—H72	109.5	C14—C15—C16	118.9 (5)
C7—C6—C1	111.7 (4)	C14—C15—C17	121.9 (5)
C7—C6—C5	126.6 (4)	C16—C15—C17	119.1 (5)
C1—C6—C5	121.6 (5)	C15—C17—C18	119.6 (5)
B1—C1—C6	105.4 (4)	C15—C17—H171	120.2
B1—C1—C2	135.8 (5)	C18—C17—H171	120.2
C6—C1—C2	118.7 (4)	C17—C18—C19	122.4 (5)
C1—C2—C3	119.8 (5)	C17—C18—H181	118.6
C1—C2—H11	119.6	C19—C18—H181	119.0
C3—C2—H11	120.6	C20—C19—C18	119.0 (5)
C2—C3—C4	121.0 (5)	C20—C19—H191	120.0
C2—C3—H12	119.0	C18—C19—H191	120.9

D—H···A	D—H	H···A	D···A	D—H···A
C9—H16···O2i	0.93	2.59	3.490 (8)	163

Table 1

Selected bond lengths (Å)

B1—O2	1.479 (6)
B1—N1	1.646 (6)
B1—O1	1.432 (6)
B1—C1	1.602 (7)

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H16⋯O2i	0.93	2.59	3.490 (8)	163

Symmetry code: (i) .