A new polymorph of dimesitylborinic acid

Matthias Kuhlmann; Thomas Baumgartner; Masood Parvez

doi:10.1107/S1600536808015638

. 2008 Jun 7;64(Pt 7):o1185. doi: 10.1107/S1600536808015638

A new polymorph of dimesitylborinic acid

Matthias Kuhlmann ^a, Thomas Baumgartner ^a, Masood Parvez ^a,^*

PMCID: PMC2961869 PMID: 21202827

Abstract

A new polymorph of dimesitylborinic acid (or hydroxydimesitylborane), C₁₈H₂₃BO, showcasing different crystal packing and symmetry, complements the previously reported polymorph [Weese, Bartlett, Murray, Olmstead & Power (1987 ▶). Inorg. Chem. 26, 2409–2413; Entwistle, Batsanov & Marder (2007 ▶). Acta Cryst. E63, o2639–o2641]. The structure of the title compound contains only one molecule in the asymmetric unit, and no O—H⋯O interactions are observed. However, molecules are linked by weak intermolecuar O—H⋯π(arene) interactions to form centrosymmetric dimers.

Related literature

For related literature, see: Cornet et al. (2003 ▶); Entwistle et al. (2007 ▶); Fraenk et al. (2001 ▶); Kuhlmann et al. (2008 ▶); Weese et al. (1987 ▶).

Experimental

Crystal data

C₁₈H₂₃BO
M _r = 266.17
Monoclinic,
a = 8.942 (4) Å
b = 8.801 (2) Å
c = 19.947 (8) Å
β = 97.800 (16)°
V = 1555.3 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 173 (2) K
0.32 × 0.24 × 0.12 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SORTAV; Blessing, 1997 ▶) T _min = 0.979, T _max = 0.992
6119 measured reflections
3542 independent reflections
2728 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.134
S = 0.91
3542 reflections
188 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: COLLECT (Hooft, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶); data reduction: SCALEPACK (Otwinowski & Minor, 1997 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808015638/om2237sup1.cif

e-64-o1185-sup1.cif^{(20.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808015638/om2237Isup2.hkl

e-64-o1185-Isup2.hkl^{(170.2KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg is the centroid of the C11–C16 phenyl ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯Cgⁱ	0.84 (2)	2.83 (2)	3.523 (2)	141 (2)

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

In the course of our studies on the synthesis and photophysical properties of boron-functionalized dithieno[3,2-b;2',3'-d]phospholes (Kuhlmann et al., 2008), we obtained a new polymorph of the title compound. It crystallizes in space group P2₁/c, which is distinct from the previously reported space group C2/c (Weese et al., 1987; Entwistle et al., 2007).

The structure is composed of unique molecules (Fig. 1) separated by normal van der Waals distances. The mean planes of the phenyl rings are inclined at approximately right angles (86.09 (4)°) with respect to each other. The structure is devoid of any classical hydrogen bonding despite the presence of a hydroxyl group. The previously reported polymorph crystallized as tetramers due to hydrogen bonding involving the OH groups (Weese et al., 1987). There are no indications of π-π stacking interactions between the phenyl groups of the symmetry related molecules in the title compound. However, the hydroxyl group is oriented towards a phenyl ring (C11-C16), thus linking the molecules by rather weak intermolecular O—H···π(arene) interactions to form centrosymmetric dimers about inversion centers (Fig. 2). The boron centers are planar with C2—B1—C11 angle 123.21 (12)°, compared to a wider corresponding angle of 126.0 (4)° reported in the other polymorph (Weese et al., 1987). The structures of trifluoromethyl analogues have also been reported, and they exhibit a similar molecular conformation (Fraenk et al., 2001; Cornet et al., 2003).

Experimental

The title compound was obtained as hydrolysis by-product in the synthesis of 2-(dimetsitylboryl)-5-phenyl-dithieno[3,2 - b;2',3'-d]phosphole, during the recrystallization of the sample from a concentrated pentane solution at 277 K.