Tetra­kis(di­meth­oxy­bor­yl)methane

The title compound, tetra­kis­(di­meth­oxy­bor­yl)methane (systematic name: octa­methyl methane­tetra­yltetra­boronate), C₉H₂₄B₄O₈ or C[B(OMe)₂]₄, is a useful synthetic inter­mediate. Crystals of this compound at 102 K conform to the ortho­rhom­bic space group Pbcn. The mol­ecules, which reside on sites of crystallographic twofold symmetry, have idealized -4 point symmetry like most other CX₄ mol­ecules in which each X group bears two non-H substituents at the 1-position. The central C atom has a slightly distorted tetra­hedral coordination geometry, with C—B bond lengths of 1.5876 (16) and 1.5905 (16) Å. One of the methoxy groups is disordered over two sets of sites; the major component has an occupancy factor of 0.676 (8).

Key indicators

• Single-crystal X-ray study
• T = 102 K
• Mean [sigma](O-B) = 0.002 Å
• Disorder in main residue
• R factor = 0.037
• wR factor = 0.100
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.497 Check
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          2 Report
PLAT978_ALERT_2_C Number C-C Bonds with Positive Residual Density           0 Note

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite          3 Note
PLAT171_ALERT_4_G The CIF-Embedded .res File Contains EADP Records          1 Report
PLAT172_ALERT_4_G The CIF-Embedded .res File Contains DFIX Records          1 Report
PLAT301_ALERT_3_G Main Residue  Disorder ............ Percentage =         10 Note
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          2 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          6 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   6 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Octamethyl methanetetrayltetraboronate

Crystal data

C9H24B4O8	Dx = 1.218 Mg m^−3
Mr = 303.52	Melting point: 350 K
Orthorhombic, Pbcn	Cu Kα radiation, λ = 1.54178 Å
a = 7.5362 (2) Å	Cell parameters from 9956 reflections
b = 15.1084 (4) Å	θ = 5.9–68.2°
c = 14.5384 (4) Å	µ = 0.83 mm^−1
V = 1655.34 (8) Å^3	T = 102 K
Z = 4	Prism, colourless
F(000) = 648	0.41 × 0.31 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer	1407 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.113
Absorption correction: integration (SADABS; Bruker, 2005)	θmax = 68.2°, θmin = 5.9°
Tmin = 0.800, Tmax = 0.921	h = −9→9
18589 measured reflections	k = −18→16
1515 independent reflections	l = −15→17

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.037	w = 1/[σ^2(Fo^2) + (0.0429P)^2 + 0.7225P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.100	(Δ/σ)max = 0.001
S = 1.07	Δρmax = 0.30 e Å^−3
1515 reflections	Δρmin = −0.19 e Å^−3
106 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.0027 (5)

Special details

Experimental. One distinct cell was identified using APEX2 (Bruker, 2010). Frame series were integrated and filtered for statistical outliers using SAINT (Bruker, 2005) then corrected for absorption by integration using SHELXTL/XPREP V2005/2 (Bruker, 2005) before using SADABS (Bruker, 2005) to sort, merge, and scale the combined data. No decay correction was applied.

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.0000	0.90014 (10)	0.7500	0.0155 (4)
B1	0.12770 (19)	0.95880 (9)	0.81186 (9)	0.0169 (3)
O11	0.08349 (11)	1.03111 (5)	0.86281 (6)	0.0192 (3)
C11	−0.09245 (17)	1.06218 (9)	0.87896 (9)	0.0227 (3)
H11A	−0.1752	1.0308	0.8384	0.034*
H11B	−0.0982	1.1258	0.8663	0.034*
H11C	−0.1249	1.0512	0.9432	0.034*
O12	0.30328 (12)	0.93573 (6)	0.81320 (7)	0.0254 (3)
C12	0.42669 (19)	0.98075 (12)	0.87109 (11)	0.0369 (4)
H12A	0.3794	0.9837	0.9338	0.055*
H12B	0.4459	1.0408	0.8477	0.055*
H12C	0.5396	0.9486	0.8715	0.055*
B2	−0.11652 (19)	0.84032 (9)	0.81675 (9)	0.0193 (3)
O21	−0.11510 (12)	0.86140 (6)	0.90809 (6)	0.0208 (3)
C21	−0.2149 (2)	0.81036 (9)	0.97275 (9)	0.0286 (4)
H21A	−0.1618	0.7514	0.9787	0.043*
H21B	−0.3375	0.8047	0.9512	0.043*
H21C	−0.2136	0.8400	1.0327	0.043*
O22	−0.21478 (16)	0.76806 (6)	0.79387 (6)	0.0334 (3)
C22A	−0.2612 (10)	0.7418 (4)	0.7017 (3)	0.0324 (11)	0.677 (14)
H22A	−0.2640	0.6771	0.6978	0.049*	0.677 (14)
H22B	−0.1728	0.7649	0.6584	0.049*	0.677 (14)
H22C	−0.3784	0.7657	0.6860	0.049*	0.677 (14)
C22B	−0.2050 (18)	0.7274 (8)	0.7041 (6)	0.0324 (11)	0.323 (14)
H22D	−0.2996	0.6833	0.6980	0.049*	0.323 (14)
H22E	−0.0895	0.6985	0.6967	0.049*	0.323 (14)
H22F	−0.2193	0.7729	0.6566	0.049*	0.323 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0213 (8)	0.0111 (7)	0.0141 (8)	0.000	0.0014 (6)	0.000
B1	0.0188 (7)	0.0150 (6)	0.0168 (6)	−0.0001 (5)	0.0010 (5)	0.0023 (5)
O11	0.0176 (5)	0.0168 (5)	0.0233 (5)	−0.0019 (3)	0.0011 (3)	−0.0041 (3)
C11	0.0220 (7)	0.0186 (6)	0.0277 (7)	0.0026 (5)	0.0022 (5)	−0.0058 (5)
O12	0.0186 (5)	0.0303 (5)	0.0273 (5)	0.0039 (4)	−0.0027 (4)	−0.0042 (4)
C12	0.0192 (7)	0.0502 (10)	0.0413 (9)	0.0013 (6)	−0.0075 (6)	−0.0095 (7)
B2	0.0273 (7)	0.0132 (6)	0.0172 (7)	−0.0029 (5)	−0.0005 (6)	0.0003 (5)
O21	0.0288 (5)	0.0187 (5)	0.0149 (5)	−0.0073 (4)	0.0024 (4)	−0.0001 (3)
C21	0.0404 (8)	0.0275 (7)	0.0178 (7)	−0.0126 (6)	0.0055 (6)	0.0019 (5)
O22	0.0583 (7)	0.0247 (5)	0.0173 (5)	−0.0221 (5)	0.0004 (4)	−0.0021 (4)
C22A	0.052 (3)	0.025 (2)	0.0204 (8)	−0.0169 (19)	−0.0027 (15)	−0.0053 (10)
C22B	0.052 (3)	0.025 (2)	0.0204 (8)	−0.0169 (19)	−0.0027 (15)	−0.0053 (10)

Geometric parameters (Å, º)

C1—B1^i	1.5876 (16)	B2—O22	1.3604 (17)
C1—B1	1.5876 (16)	B2—O21	1.3656 (16)
C1—B2^i	1.5905 (16)	O21—C21	1.4295 (15)
C1—B2	1.5905 (16)	C21—H21A	0.9800
B1—O11	1.3613 (16)	C21—H21B	0.9800
B1—O12	1.3685 (17)	C21—H21C	0.9800
O11—C11	1.4260 (15)	O22—C22A	1.441 (4)
C11—H11A	0.9800	O22—C22B	1.444 (8)
C11—H11B	0.9800	C22A—H22A	0.9800
C11—H11C	0.9800	C22A—H22B	0.9800
O12—C12	1.4268 (18)	C22A—H22C	0.9800
C12—H12A	0.9800	C22B—H22D	0.9800
C12—H12B	0.9800	C22B—H22E	0.9800
C12—H12C	0.9800	C22B—H22F	0.9800
B1^i—C1—B1	112.12 (13)	O22—B2—C1	127.39 (11)
B1^i—C1—B2^i	107.83 (7)	O21—B2—C1	117.16 (10)
B1—C1—B2^i	109.16 (7)	B2—O21—C21	120.63 (10)
B1^i—C1—B2	109.16 (7)	O21—C21—H21A	109.5
B1—C1—B2	107.83 (7)	O21—C21—H21B	109.5
B2^i—C1—B2	110.74 (14)	H21A—C21—H21B	109.5
O11—B1—O12	115.68 (11)	O21—C21—H21C	109.5
O11—B1—C1	127.44 (11)	H21A—C21—H21C	109.5
O12—B1—C1	116.87 (10)	H21B—C21—H21C	109.5
B1—O11—C11	125.54 (10)	B2—O22—C22A	125.5 (2)
O11—C11—H11A	109.5	B2—O22—C22B	122.3 (5)
O11—C11—H11B	109.5	O22—C22A—H22A	109.5
H11A—C11—H11B	109.5	O22—C22A—H22B	109.5
O11—C11—H11C	109.5	H22A—C22A—H22B	109.5
H11A—C11—H11C	109.5	O22—C22A—H22C	109.5
H11B—C11—H11C	109.5	H22A—C22A—H22C	109.5
B1—O12—C12	121.15 (11)	H22B—C22A—H22C	109.5
O12—C12—H12A	109.5	O22—C22B—H22D	109.5
O12—C12—H12B	109.5	O22—C22B—H22E	109.5
H12A—C12—H12B	109.5	H22D—C22B—H22E	109.5
O12—C12—H12C	109.5	O22—C22B—H22F	109.5
H12A—C12—H12C	109.5	H22D—C22B—H22F	109.5
H12B—C12—H12C	109.5	H22E—C22B—H22F	109.5
O22—B2—O21	115.42 (11)

Symmetry code: (i) −x, y, −z+3/2.