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Acta Cryst. (2009). E65, m179    [ doi:10.1107/S1600536808042748 ]

Bis([mu]-dimesitylborinato-[kappa]2O:O)bis[(2-methylpyridine-[kappa]N)lithium]

K. P. Saravana, J.-H. Son and J. D. Hoefelmeyer

Abstract top

The title compound, [Li2(C18H22BO)2(C6H7N)2], is a lithium dimesitylboroxide dimer in which the lithium cation is also coordinated by one molecule of 2-methylpyridine. At the core of the structure is an Li2O2 four-membered ring. The structure is centrosymmetric with an inversion centre midway between two Li atoms. Intermolecular C-H...[pi] interactions and [pi]-[pi] interactions between the 2-methylpyridine rings exist [centroid-centroid distance = 3.6312 (16) Å].

Comment top

The title compound is structurally similar to the compounds reported in the literature (Weese et al., 1987; Gibson et al., 1997; Cole et al., 2004). The molecule contains a staggered conformation of C—B—C planes about the Li2O2 core, and pyramidalization about the three coordinate lithium(I).

The title compound consist of a lithium(I) cation coordinated to two dimesitylboroxide anions (Li1—O1 = 1.853 (5) Å and Li1—O1i = 1.873 (5) Å) [symmetry code: (i) -x + 1, -y + 2, -z] and one molecule of 2-methylpyridine (Li1—N1 = 2.084 (5) Å). The environment around boron is distorted trigonal planar (sum of the angles around B1 = 360.0°). The asymmetric units are joined via planar Li2O2 four member ring (Li1···Li1i = 2.444 (8) Å). The lithium cation is three-coordinate and slightly pyramidalized (sum of the angles around Li1 = 356.03°). The O1—Li1—O1i and O1i—Li1—N1 angles deviate from an ideal trigonal planar geometry (98.0 (2) ° and 138.6 (3) °, respectively), with the expanded angle a result of steric repulsion between the methyl group (C7) of 2-methylpyridine and dimesitylboroxide group of the adjoining asymmetric unit. The mean plane of boron triangle forms a 48.96 (16) ° angle against the Li2O2 plane. The crystal structure contains intermolecular C5—H5···Cg1ii interaction with H···Cg = 2.96 Å, C—H···Cg angle 146° and C···Cg = 3.787 (3) Å (Cg1 is centroid of C8—C13) [symmetry code: (ii) x, -1 + y, z]. Intermolecular face to face π–π interaction between the 2-methylpyridine rings occurs with Cg2···Cg2iii = 3.6312 (`6) Å (Cg2 is centroid of N1—C6) [symmetry code: (iii) -x + 1, -y + 1, -z].

Related literature top

For related structures, see: Weese et al. (1987); Gibson et al. (1997); Cole et al. (2004). Cg1 is the centroid of the C8–C13 ring.

Experimental top

To a solution of 2-methylpyridine (0.45 ml, 3.8 mmol), n-butyllithium (1.6 M, 2.5 ml, 4.2 mmol) in 10 ml hexane was added dropwise through an addition funnel at -78 °C under inert atmosphere. The resulting red color solution was stirred for 30 minutes at -78 °C. Meanwhile, dimesitylboronfluoride (1.0 g, 3.8 mmol) was dissolved in hexane (10 ml) in a round bottom flask and kept under nitrogen atmosphere. The dimesitylboronfluoride solution was transferred to the organolithium by cannula. The resultant yellow color solution was stirred (18 h) under nitrogen atmosphere. The product was filtered through a frit and a yellowish precipitate formed upon exposure to air. The product was dissolved in toluene, and crystals were recovered upon slow evaporation of the solvent.

Refinement top

C-bound H atoms were positioned geometrically with C—H (aromatic) = 0.95 Å and C—H (methyl) = 0.98 Å and allowed to ride on the parent atoms with Uiso(H) = 1.2Ueq(C) and Uiso(H) = 1.5Ueq(C), respectively.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. ORTEP drawing of Bis-µ2-[(2-methylpyridine)lithium(I)]-bis(dimesitylboroxide). Unlabled atoms are related with labeled part by inversion symmetry. Displacement ellipsoids are drawn at the 50% probability level. H atoms are omitted for clarity.
[Figure 2] Fig. 2. Packing diagram of Bis-µ2-[(2-methylpyridine)lithium(I)]-bis(dimesitylboroxide) viewed along a axis. Dotted lines show C— H···π and π–π interactions.
Bis(µ-dimesitylborinato-κ2O:O)bis[(2-methylpyridine-κN)lithium] top
Crystal data top
[Li2(C18H22BO)2(C6H7N)2]F(000) = 784
Mr = 730.46Dx = 1.177 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1946 reflections
a = 8.6075 (11) Åθ = 2.5–23.1°
b = 9.1307 (11) ŵ = 0.07 mm−1
c = 26.220 (3) ÅT = 100 K
β = 90.124 (2)°Needle, colorless
V = 2060.7 (4) Å30.63 × 0.19 × 0.14 mm
Z = 2
Data collection top
Bruker SMART APEXII
diffractometer		2848 independent reflections
Radiation source: fine-focus sealed tube2011 reflections with I > 2σ(I)
graphiteRint = 0.036
ω scansθmax = 23.4°, θmin = 1.6°
Absorption correction: multi-scan
(SADABS; Bruker, 2006)		h = −9→9
Tmin = 0.958, Tmax = 0.990k = −10→9
8145 measured reflectionsl = −28→29
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.043Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.140H-atom parameters constrained
S = 1.26 w = 1/[σ2(Fo2) + (0.1P)2]
where P = (Fo2 + 2Fc2)/3
2848 reflections(Δ/σ)max = 0.001
260 parametersΔρmax = 0.30 e Å−3
0 restraintsΔρmin = −0.24 e Å−3
Crystal data top
[Li2(C18H22BO)2(C6H7N)2]V = 2060.7 (4) Å3
Mr = 730.46Z = 2
Monoclinic, P21/nMo Kα radiation
a = 8.6075 (11) ŵ = 0.07 mm−1
b = 9.1307 (11) ÅT = 100 K
c = 26.220 (3) Å0.63 × 0.19 × 0.14 mm
β = 90.124 (2)°
Data collection top
Bruker SMART APEXII
diffractometer		2848 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2006)		2011 reflections with I > 2σ(I)
Tmin = 0.958, Tmax = 0.990Rint = 0.036
8145 measured reflectionsθmax = 23.4°
Refinement top
R[F2 > 2σ(F2)] = 0.043H-atom parameters constrained
wR(F2) = 0.140Δρmax = 0.30 e Å−3
S = 1.26Δρmin = −0.24 e Å−3
2848 reflectionsAbsolute structure: ?
260 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C20.7338 (3)0.5897 (3)−0.00706 (10)0.0223 (6)
C30.7904 (3)0.4572 (3)0.01163 (10)0.0263 (7)
H30.86960.4059−0.00620.032*
C40.7299 (3)0.4011 (3)0.05639 (10)0.0282 (7)
H40.76810.31140.06990.034*
C50.6140 (3)0.4763 (3)0.08128 (10)0.0281 (7)
H50.56990.43950.11190.034*
C60.5637 (3)0.6068 (3)0.06045 (10)0.0253 (7)
H60.48310.65840.07740.030*
C70.7948 (3)0.6533 (3)−0.05569 (10)0.0297 (7)
H7A0.84230.5755−0.07620.045*
H7B0.87300.7281−0.04780.045*
H7C0.70920.6979−0.07490.045*
C80.4570 (3)1.0810 (3)0.13862 (9)0.0197 (6)
C90.3566 (3)1.1589 (3)0.17090 (9)0.0208 (6)
C100.4168 (3)1.2560 (3)0.20712 (9)0.0236 (6)
H100.34691.31110.22750.028*
C110.5757 (3)1.2744 (3)0.21418 (10)0.0218 (6)
C120.6750 (3)1.1964 (3)0.18272 (10)0.0232 (7)
H120.78411.20700.18690.028*
C130.6178 (3)1.1022 (3)0.14482 (10)0.0222 (6)
C140.1828 (3)1.1379 (3)0.16953 (10)0.0276 (7)
H14A0.15581.04660.18700.041*
H14B0.14751.13310.13400.041*
H14C0.13221.22040.18670.041*
C150.6359 (3)1.3743 (3)0.25549 (10)0.0304 (7)
H15A0.74691.35620.26080.046*
H15B0.57961.35520.28720.046*
H15C0.62021.47650.24530.046*
C160.7350 (3)1.0196 (3)0.11262 (10)0.0272 (7)
H16A0.71700.91410.11600.041*
H16B0.84031.04310.12430.041*
H16C0.72331.04830.07680.041*
C170.2773 (3)0.8374 (3)0.11617 (9)0.0214 (6)
C180.3143 (3)0.7485 (3)0.15886 (9)0.0227 (6)
C190.2096 (3)0.6436 (3)0.17580 (10)0.0230 (7)
H190.23830.58300.20370.028*
C200.0641 (3)0.6238 (3)0.15342 (10)0.0235 (7)
C210.0300 (3)0.7095 (3)0.11096 (10)0.0228 (6)
H21−0.06750.69710.09450.027*
C220.1331 (3)0.8122 (3)0.09178 (9)0.0212 (6)
C230.4655 (3)0.7641 (3)0.18735 (10)0.0312 (7)
H23A0.46460.85540.20700.047*
H23B0.55170.76620.16300.047*
H23C0.47870.68090.21060.047*
C24−0.0507 (3)0.5159 (3)0.17434 (11)0.0358 (8)
H24A−0.04580.42500.15450.054*
H24B−0.15560.55710.17210.054*
H24C−0.02560.49510.21010.054*
C250.0840 (3)0.8989 (3)0.04561 (10)0.0276 (7)
H25A−0.01980.86750.03480.041*
H25B0.15810.88240.01790.041*
H25C0.08171.00340.05420.041*
Li10.5311 (5)0.8695 (5)−0.00153 (16)0.0253 (10)
B10.3913 (3)0.9657 (3)0.09683 (11)0.0203 (7)
N10.6228 (3)0.6653 (2)0.01732 (8)0.0236 (6)
O10.43136 (19)0.97903 (18)0.04806 (6)0.0246 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C20.0251 (16)0.0196 (15)0.0222 (15)0.0003 (12)0.0001 (13)−0.0035 (12)
C30.0253 (16)0.0231 (15)0.0306 (16)0.0050 (13)0.0003 (13)−0.0029 (13)
C40.0328 (17)0.0207 (15)0.0312 (17)0.0029 (13)−0.0033 (14)0.0031 (13)
C50.0326 (17)0.0260 (16)0.0258 (16)−0.0022 (13)−0.0004 (14)0.0043 (13)
C60.0231 (16)0.0281 (16)0.0246 (16)0.0015 (13)0.0027 (13)−0.0027 (13)
C70.0296 (16)0.0274 (16)0.0320 (17)0.0042 (13)0.0060 (13)0.0009 (13)
C80.0238 (15)0.0167 (13)0.0186 (14)0.0002 (12)0.0031 (12)0.0072 (11)
C90.0209 (15)0.0236 (15)0.0181 (14)0.0007 (12)0.0018 (12)0.0030 (12)
C100.0266 (16)0.0229 (14)0.0214 (15)0.0038 (13)0.0047 (12)0.0024 (12)
C110.0233 (16)0.0215 (15)0.0205 (14)−0.0017 (12)0.0001 (13)0.0046 (12)
C120.0225 (15)0.0219 (14)0.0253 (15)−0.0031 (12)0.0009 (13)0.0088 (12)
C130.0244 (16)0.0186 (14)0.0235 (15)0.0014 (12)0.0053 (12)0.0068 (12)
C140.0252 (16)0.0308 (16)0.0267 (16)0.0022 (13)0.0037 (13)−0.0041 (13)
C150.0308 (17)0.0310 (16)0.0293 (16)−0.0039 (13)0.0005 (14)0.0018 (13)
C160.0207 (15)0.0257 (15)0.0352 (16)0.0009 (12)0.0047 (13)0.0008 (13)
C170.0276 (16)0.0188 (14)0.0176 (14)0.0042 (12)0.0042 (12)−0.0023 (11)
C180.0299 (17)0.0207 (14)0.0175 (14)0.0030 (13)0.0042 (12)0.0014 (12)
C190.0289 (16)0.0201 (14)0.0200 (14)0.0028 (13)0.0040 (13)0.0026 (11)
C200.0256 (16)0.0204 (15)0.0245 (15)−0.0010 (12)0.0083 (13)−0.0031 (12)
C210.0199 (15)0.0243 (15)0.0243 (15)0.0031 (12)0.0026 (12)−0.0041 (12)
C220.0275 (16)0.0195 (14)0.0167 (14)0.0034 (12)0.0045 (12)−0.0047 (11)
C230.0387 (18)0.0306 (16)0.0242 (15)−0.0017 (14)−0.0066 (14)0.0074 (13)
C240.0365 (18)0.0321 (17)0.0387 (17)−0.0080 (14)0.0045 (15)0.0021 (14)
C250.0262 (16)0.0302 (16)0.0264 (15)0.0024 (13)−0.0014 (13)−0.0006 (13)
Li10.026 (3)0.025 (2)0.025 (2)−0.003 (2)0.005 (2)−0.0003 (19)
B10.0181 (17)0.0217 (16)0.0211 (17)0.0092 (13)0.0021 (14)0.0010 (13)
N10.0270 (13)0.0230 (12)0.0208 (13)0.0008 (10)0.0007 (11)−0.0012 (10)
O10.0290 (11)0.0235 (10)0.0212 (11)0.0030 (8)0.0036 (9)0.0023 (8)
Geometric parameters (Å, °) top
C2—N11.342 (3)C15—H15C0.9800
C2—C31.393 (4)C16—H16A0.9800
C2—C71.497 (4)C16—H16B0.9800
C3—C41.383 (4)C16—H16C0.9800
C3—H30.9500C17—C221.414 (4)
C4—C51.377 (4)C17—C181.419 (3)
C4—H40.9500C17—B11.611 (4)
C5—C61.380 (4)C18—C191.389 (3)
C5—H50.9500C18—C231.506 (4)
C6—N11.351 (3)C19—C201.393 (4)
C6—H60.9500C19—H190.9500
C7—H7A0.9800C20—C211.392 (4)
C7—H7B0.9800C20—C241.500 (4)
C7—H7C0.9800C21—C221.386 (4)
C8—C91.405 (3)C21—H210.9500
C8—C131.406 (3)C22—C251.506 (3)
C8—B11.620 (4)C23—H23A0.9800
C9—C101.398 (3)C23—H23B0.9800
C9—C141.509 (4)C23—H23C0.9800
C10—C111.390 (4)C24—H24A0.9800
C10—H100.9500C24—H24B0.9800
C11—C121.386 (4)C24—H24C0.9800
C11—C151.507 (4)C25—H25A0.9800
C12—C131.403 (4)C25—H25B0.9800
C12—H120.9500C25—H25C0.9800
C13—C161.517 (4)Li1—O11.853 (5)
C14—H14A0.9800Li1—O1i1.873 (5)
C14—H14B0.9800Li1—N12.084 (5)
C14—H14C0.9800Li1—Li1i2.444 (8)
C15—H15A0.9800B1—O11.331 (3)
C15—H15B0.9800O1—Li1i1.873 (5)
N1—C2—C3121.8 (2)C13—C16—H16C109.5
N1—C2—C7117.2 (2)H16A—C16—H16C109.5
C3—C2—C7120.9 (3)H16B—C16—H16C109.5
C4—C3—C2119.3 (3)C22—C17—C18117.3 (2)
C4—C3—H3120.4C22—C17—B1120.7 (2)
C2—C3—H3120.4C18—C17—B1121.9 (2)
C5—C4—C3119.5 (2)C19—C18—C17120.2 (2)
C5—C4—H4120.3C19—C18—C23117.9 (2)
C3—C4—H4120.3C17—C18—C23122.0 (2)
C4—C5—C6118.0 (3)C18—C19—C20122.6 (2)
C4—C5—H5121.0C18—C19—H19118.7
C6—C5—H5121.0C20—C19—H19118.7
N1—C6—C5123.7 (3)C21—C20—C19116.8 (2)
N1—C6—H6118.2C21—C20—C24121.6 (2)
C5—C6—H6118.2C19—C20—C24121.6 (2)
C2—C7—H7A109.5C22—C21—C20122.5 (2)
C2—C7—H7B109.5C22—C21—H21118.8
H7A—C7—H7B109.5C20—C21—H21118.8
C2—C7—H7C109.5C21—C22—C17120.5 (2)
H7A—C7—H7C109.5C21—C22—C25118.0 (2)
H7B—C7—H7C109.5C17—C22—C25121.5 (2)
C9—C8—C13117.9 (2)C18—C23—H23A109.5
C9—C8—B1121.5 (2)C18—C23—H23B109.5
C13—C8—B1120.6 (2)H23A—C23—H23B109.5
C10—C9—C8120.2 (2)C18—C23—H23C109.5
C10—C9—C14117.6 (2)H23A—C23—H23C109.5
C8—C9—C14122.2 (2)H23B—C23—H23C109.5
C11—C10—C9122.0 (3)C20—C24—H24A109.5
C11—C10—H10119.0C20—C24—H24B109.5
C9—C10—H10119.0H24A—C24—H24B109.5
C12—C11—C10117.8 (2)C20—C24—H24C109.5
C12—C11—C15121.8 (2)H24A—C24—H24C109.5
C10—C11—C15120.3 (2)H24B—C24—H24C109.5
C11—C12—C13121.4 (2)C22—C25—H25A109.5
C11—C12—H12119.3C22—C25—H25B109.5
C13—C12—H12119.3H25A—C25—H25B109.5
C12—C13—C8120.7 (2)C22—C25—H25C109.5
C12—C13—C16117.8 (2)H25A—C25—H25C109.5
C8—C13—C16121.5 (2)H25B—C25—H25C109.5
C9—C14—H14A109.5O1—Li1—O1i98.0 (2)
C9—C14—H14B109.5O1—Li1—N1119.5 (2)
H14A—C14—H14B109.5O1i—Li1—N1138.6 (3)
C9—C14—H14C109.5O1—Li1—Li1i49.36 (16)
H14A—C14—H14C109.5O1i—Li1—Li1i48.66 (16)
H14B—C14—H14C109.5N1—Li1—Li1i161.4 (3)
C11—C15—H15A109.5O1—B1—C17121.9 (2)
C11—C15—H15B109.5O1—B1—C8120.0 (2)
H15A—C15—H15B109.5C17—B1—C8118.1 (2)
C11—C15—H15C109.5C2—N1—C6117.7 (2)
H15A—C15—H15C109.5C2—N1—Li1128.1 (2)
H15B—C15—H15C109.5C6—N1—Li1114.2 (2)
C13—C16—H16A109.5B1—O1—Li1138.3 (2)
C13—C16—H16B109.5B1—O1—Li1i137.6 (2)
H16A—C16—H16B109.5Li1—O1—Li1i82.0 (2)
N1—C2—C3—C40.4 (4)C18—C17—C22—C213.3 (4)
C7—C2—C3—C4−179.3 (2)B1—C17—C22—C21−174.9 (2)
C2—C3—C4—C50.7 (4)C18—C17—C22—C25−179.0 (2)
C3—C4—C5—C6−0.7 (4)B1—C17—C22—C252.8 (4)
C4—C5—C6—N1−0.5 (4)C22—C17—B1—O1−50.9 (3)
C13—C8—C9—C101.2 (3)C18—C17—B1—O1131.0 (3)
B1—C8—C9—C10179.0 (2)C22—C17—B1—C8128.9 (3)
C13—C8—C9—C14−176.5 (2)C18—C17—B1—C8−49.2 (3)
B1—C8—C9—C141.4 (3)C9—C8—B1—O1125.9 (3)
C8—C9—C10—C11−2.9 (4)C13—C8—B1—O1−56.3 (3)
C14—C9—C10—C11174.9 (2)C9—C8—B1—C17−53.9 (3)
C9—C10—C11—C122.2 (4)C13—C8—B1—C17123.9 (3)
C9—C10—C11—C15−176.8 (2)C3—C2—N1—C6−1.6 (3)
C10—C11—C12—C130.2 (4)C7—C2—N1—C6178.1 (2)
C15—C11—C12—C13179.1 (2)C3—C2—N1—Li1176.2 (2)
C11—C12—C13—C8−1.8 (4)C7—C2—N1—Li1−4.1 (3)
C11—C12—C13—C16−179.2 (2)C5—C6—N1—C21.7 (4)
C9—C8—C13—C121.1 (3)C5—C6—N1—Li1−176.4 (2)
B1—C8—C13—C12−176.8 (2)O1—Li1—N1—C2−159.0 (2)
C9—C8—C13—C16178.4 (2)O1i—Li1—N1—C2−7.0 (5)
B1—C8—C13—C160.5 (3)Li1i—Li1—N1—C2−110.7 (10)
C22—C17—C18—C19−1.2 (4)O1—Li1—N1—C618.8 (3)
B1—C17—C18—C19177.0 (2)O1i—Li1—N1—C6170.8 (3)
C22—C17—C18—C23179.1 (2)Li1i—Li1—N1—C667.1 (11)
B1—C17—C18—C23−2.7 (4)C17—B1—O1—Li1−60.0 (4)
C17—C18—C19—C20−2.1 (4)C8—B1—O1—Li1120.2 (3)
C23—C18—C19—C20177.6 (2)C17—B1—O1—Li1i143.1 (3)
C18—C19—C20—C213.3 (4)C8—B1—O1—Li1i−36.6 (4)
C18—C19—C20—C24−176.3 (2)O1i—Li1—O1—B1−164.5 (3)
C19—C20—C21—C22−1.1 (4)N1—Li1—O1—B1−2.8 (5)
C24—C20—C21—C22178.4 (2)Li1i—Li1—O1—B1−164.5 (3)
C20—C21—C22—C17−2.1 (4)O1i—Li1—O1—Li1i0.0
C20—C21—C22—C25−180.0 (2)N1—Li1—O1—Li1i161.7 (4)
Symmetry codes: (i) −x+1, −y+2, −z.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···Cg1ii0.952.963.787 (3)146
Symmetry codes: (ii) x, y−1, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···Cg1i0.952.963.787 (3)146
Symmetry codes: (i) x, y−1, z.
Acknowledgements top

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).

references
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