Oxybis(dimesitylborane) dichloro­methane hemisolvate

Jung-Ho Son; James D Hoefelmeyer

doi:10.1107/S160053680804275X

. 2009 Feb 6;65(Pt 3):o470. doi: 10.1107/S160053680804275X

Oxybis(dimesitylborane) dichloromethane hemisolvate

Jung-Ho Son ^a, James D Hoefelmeyer ^a,^*

PMCID: PMC2968469 PMID: 21582141

Abstract

The title compound, C₃₆H₄₄B₂O·0.5CH₂Cl₂, contains an almost linear O—B—O linkage [177.23 (15)°] and approximately orthogonal [interplanar angles 89.49 (5) and 80.77 (4)°] trigonal planar B centers, consistent with the previously reported non-solvated structure [Cardinet al. (1983). J. Chem. Res. (S), p. 93]. Intermolecular C—H⋯π interactions exist between mesityl groups, with a C—H⋯centroid separation of 3.6535 (18) Å. The dichloromethane molecules lie on twofold rotation axes.

Related literature

For the non-solvated structure, see: Cardin et al. (1983 ▶). For molecular orbital calculations concerning the parent compound (H₂B)₂O, see: Fjeldberg et al. (1980 ▶).

Experimental

Crystal data

C₃₆H₄₄B₂O·0.5CH₂Cl₂
M _r = 556.80
Monoclinic,
a = 36.563 (2) Å
b = 8.3129 (5) Å
c = 21.6346 (13) Å
β = 102.459 (1)°
V = 6420.9 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.15 mm⁻¹
T = 100 (2) K
0.80 × 0.35 × 0.28 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ▶) T _min = 0.892, T _max = 0.960
30958 measured reflections
5864 independent reflections
4475 reflections with I > 2σ(I)
R _int = 0.038

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.108
S = 1.01
5864 reflections
378 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: SMART (Bruker, 2003 ▶); cell refinement: SAINT (Bruker, 2003 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680804275X/bi2327sup1.cif

e-65-0o470-sup1.cif^{(28KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680804275X/bi2327Isup2.hkl

e-65-0o470-Isup2.hkl^{(281.4KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C18—H18A⋯Cgⁱ	0.98	2.80	3.649 (4)	145

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Symmetry code: (i) Inline graphic . Cg is the centroid of the C19–C24 ring.

Acknowledgments

This work was supported by funding from the South Dakota 2010 Initiative, Center for Research and Development of Light-Activated Materials. Purchase of the X-ray diffractometer was made possible with funds from the National Science Foundation (EPS-0554609).

supplementary crystallographic information

Comment

The overall geometry of the oxybis(dimesitylborane) molecule is very similar to the previously reported non-solvated structure (Cardin et al., 1983). In the title compound, B—O = 1.351 (2) Å and B1—O1—B2 = 177.23 (15)°, compared with the non-solvated structure where B—O = 1.36 (2) Å and B—O—B = 165.5 (12) °. The angle between the boron trigonal planes (ψ) is 87.16 (5) ° which is larger than that of the previous structure (85 °). Ab initio molecular orbital calculation of (H₂B)₂O (Fjeldberg et al., 1980) has predicted that as the B—O—B angle approaches linearity, the ψ angle should approach 90°, which is consistent with the present structure, showing B=O=B character. Orthogonality of the mesityl groups 89.49 (5) ° and 80.77 (4) ° attached on the same boron atom is a similar structural feature to the previous report (85.5 ° and 81.3 °; Cardin et al., 1983). Intermolecular C—H···π interaction between mesityl groups exists with C···π separation of 3.6535 (18) ° (Table 1).

Experimental

The title compound was isolated as a biproduct from the reaction of dimesitylboron fluoride and organolithium reagent in tetrahydrofuran. After removal of THF in vacuo, the residue was extracted with dichloromethane. The slow evaporation of dichloromethane under nitrogen atmosphere led to formation of colorless prismatic crystals. It is probable that unintended inclusion of water hydrolyzes the B—F bond to an intermediate borinic acid that undergoes condensation to form the B—O—B linkage.