Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010901172X/dn3110sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010901172X/dn3110Isup2.hkl |
CCDC reference: 735102
For related literature, see: Allen (2002); Bernstein et al. (1995); Binder et al. (1993); Gainsford & Kemmitt (2004, 2005); Izod et al. (2007); Kemmitt & Gainsford (2009); Knizek et al. (2006); Ruiz et al. (2008); Wagler & Hill (2008).
NaAlH4 (0.65 g, 12 mmol) was added in small aliquots over a period of 15 min to a rapidly stirred flask containing NaB[OCH(CH3)2]4 (2.70 g, 10 mmol) in tetrahydrofuran (100 ml)at 273 K. The reaction mixture was allowed to return to room temperature and was stirred for 16 h. The reaction mixture was filtered and the volume reduced under partial vacuum. After the reaction mixture had been left in a freezer (261 K) for 16 h, the product appeared as colourless needles, which were filtered off and dried in vacuo (yield 0.8 g, 84%). 1H NMR (d6-DMSO): δ 0.9, (d, 6.1 Hz, CH3, 6H), 2.01 (q, 88 Hz, BH3, 3H), 3.17(sept, CH, 1H) p.p.m. 13C NMR (d6-DMSO): δ 24.72 (CH3), 61.84 (CH) p.p.m. 11B NMR (d6-DMSO): δ -9.7 p.p.m. (88 Hz).
The positional parameters of all H atoms were freely refined, with Uiso(H) fixed at 1.5 or 1.2 (for H4) times Ueq of their carrier atoms. A total of 37 of the 1077 expected reflections within the sinθ/λ limit of 0.60 either could not be processed correctly (25) or were omitted as outliers (12).
Data collection: CrystalClear (Rigaku, 2005); cell refinement: FSProcess in Process-Auto (Rigaku, 1998); data reduction: FSProcess in Process-Auto (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP in WinGX (Farrugia, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
[Na(C3H10BO)] | F(000) = 416 |
Mr = 95.91 | Dx = 1.073 Mg m−3 |
Orthorhombic, Pbca | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 4075 reflections |
a = 5.5071 (11) Å | θ = 6.8–72.0° |
b = 11.094 (2) Å | µ = 1.19 mm−1 |
c = 19.438 (4) Å | T = 173 K |
V = 1187.6 (4) Å3 | Rod, colourless |
Z = 8 | 0.5 × 0.05 × 0.02 mm |
Rigaku Spider diffractometer | 1119 independent reflections |
Radiation source: Rigaku MM007 rotating anode | 849 reflections with I > 2σ(I) |
Rigaku VariMax-HF Confocal Optical System monochromator | Rint = 0.104 |
Detector resolution: 10 pixels mm-1 | θmax = 72.2°, θmin = 8.0° |
ω–scans | h = −6→6 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −13→13 |
Tmin = 0.492, Tmax = 1.0 | l = −21→22 |
9917 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.070 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.194 | Only H-atom coordinates refined |
S = 1.08 | w = 1/[σ2(Fo2) + (0.1163P)2] where P = (Fo2 + 2Fc2)/3 |
1119 reflections | (Δ/σ)max < 0.001 |
85 parameters | Δρmax = 0.49 e Å−3 |
0 restraints | Δρmin = −0.35 e Å−3 |
[Na(C3H10BO)] | V = 1187.6 (4) Å3 |
Mr = 95.91 | Z = 8 |
Orthorhombic, Pbca | Cu Kα radiation |
a = 5.5071 (11) Å | µ = 1.19 mm−1 |
b = 11.094 (2) Å | T = 173 K |
c = 19.438 (4) Å | 0.5 × 0.05 × 0.02 mm |
Rigaku Spider diffractometer | 1119 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 849 reflections with I > 2σ(I) |
Tmin = 0.492, Tmax = 1.0 | Rint = 0.104 |
9917 measured reflections |
R[F2 > 2σ(F2)] = 0.070 | 0 restraints |
wR(F2) = 0.194 | Only H-atom coordinates refined |
S = 1.08 | Δρmax = 0.49 e Å−3 |
1119 reflections | Δρmin = −0.35 e Å−3 |
85 parameters |
Experimental. Because of the small crystal size, X-ray data collection was not possible on a standard sealed tube/CCD system, but was achieved with a microfocus rotating anode system (Rigaku MM007) with confocal optics (Osmic-Rigaku) delivering copper K-alpha radiation to the sample, coupled with a wrap-around image-plate detector (Rigagu Spider). |
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. |
x | y | z | Uiso*/Ueq | ||
Na1 | 0.29141 (16) | 0.39362 (9) | 0.49521 (5) | 0.0498 (5) | |
O1 | 0.6138 (3) | 0.45558 (14) | 0.42507 (8) | 0.0472 (6) | |
C1 | 0.4338 (6) | 0.5736 (3) | 0.33565 (17) | 0.0645 (8) | |
H5 | 0.423 (6) | 0.585 (3) | 0.288 (2) | 0.097* | |
H6 | 0.493 (7) | 0.642 (3) | 0.358 (2) | 0.097* | |
H7 | 0.260 (8) | 0.558 (3) | 0.3569 (19) | 0.097* | |
C2 | 0.5954 (4) | 0.4665 (2) | 0.35194 (13) | 0.0490 (7) | |
H4 | 0.769 (5) | 0.483 (2) | 0.3363 (12) | 0.059* | |
C3 | 0.5002 (6) | 0.3528 (3) | 0.31911 (18) | 0.0636 (8) | |
H8 | 0.494 (7) | 0.357 (3) | 0.272 (2) | 0.095* | |
H9 | 0.335 (7) | 0.331 (3) | 0.3394 (18) | 0.095* | |
H10 | 0.609 (6) | 0.286 (3) | 0.3333 (16) | 0.095* | |
B1 | 0.7916 (4) | 0.3656 (3) | 0.45085 (18) | 0.0509 (8) | |
H1 | 0.824 (7) | 0.379 (3) | 0.5120 (17) | 0.076* | |
H2 | 0.971 (6) | 0.374 (3) | 0.4219 (14) | 0.076* | |
H3 | 0.723 (5) | 0.270 (3) | 0.4416 (15) | 0.076* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Na1 | 0.0453 (6) | 0.0586 (8) | 0.0456 (9) | −0.0045 (4) | 0.0024 (3) | 0.0002 (4) |
O1 | 0.0451 (9) | 0.0592 (10) | 0.0373 (12) | 0.0048 (6) | 0.0011 (6) | 0.0020 (7) |
C1 | 0.0811 (19) | 0.0673 (16) | 0.045 (2) | 0.0029 (14) | −0.0133 (15) | 0.0038 (15) |
C2 | 0.0495 (12) | 0.0648 (14) | 0.0328 (16) | −0.0033 (10) | 0.0027 (9) | 0.0024 (11) |
C3 | 0.0690 (16) | 0.0741 (18) | 0.048 (2) | −0.0009 (14) | −0.0045 (13) | −0.0091 (15) |
B1 | 0.0438 (13) | 0.0641 (17) | 0.045 (2) | 0.0041 (11) | 0.0002 (10) | 0.0064 (14) |
Na1—O1i | 2.3393 (19) | C1—H6 | 0.94 (4) |
Na1—O1 | 2.3416 (17) | C1—H7 | 1.05 (4) |
Na1—H2ii | 2.28 (3) | C2—C3 | 1.508 (4) |
Na1—H3iii | 2.22 (3) | C2—H4 | 1.02 (3) |
Na1—B1ii | 2.901 (3) | C3—H8 | 0.92 (4) |
Na1—B1i | 2.906 (3) | C3—H9 | 1.02 (4) |
O1—C2 | 1.430 (3) | C3—H10 | 1.00 (4) |
O1—B1 | 1.486 (3) | B1—Na1iv | 3.060 (3) |
O1—Na1i | 2.3393 (19) | B1—H1 | 1.21 (3) |
C1—C2 | 1.517 (4) | B1—H2 | 1.14 (3) |
C1—H5 | 0.93 (4) | B1—H3 | 1.14 (3) |
O1i—Na1—O1 | 90.38 (6) | O1—C2—C1 | 108.4 (2) |
O1—Na1—H2ii | 104.5 (8) | C3—C2—C1 | 111.2 (2) |
O1—Na1—H3iii | 133.6 (7) | O1—C2—H4 | 104.2 (14) |
H2ii—Na1—H3iii | 97.8 (11) | C3—C2—H4 | 110.3 (14) |
C2—O1—B1 | 116.04 (19) | C1—C2—H4 | 110.5 (15) |
C2—O1—Na1i | 127.83 (12) | C2—C3—H8 | 113 (2) |
B1—O1—Na1i | 96.32 (16) | C2—C3—H9 | 110 (2) |
C2—O1—Na1 | 123.36 (13) | H8—C3—H9 | 111 (3) |
B1—O1—Na1 | 96.09 (14) | C2—C3—H10 | 107 (2) |
Na1i—O1—Na1 | 89.62 (6) | H8—C3—H10 | 109 (3) |
C2—C1—H5 | 111 (2) | H9—C3—H10 | 105 (3) |
C2—C1—H6 | 110 (2) | O1—B1—H1 | 110.2 (16) |
H5—C1—H6 | 111 (3) | O1—B1—H2 | 110.4 (15) |
C2—C1—H7 | 109 (2) | H1—B1—H2 | 110 (2) |
H5—C1—H7 | 111 (3) | O1—B1—H3 | 110.7 (14) |
H6—C1—H7 | 106 (3) | H1—B1—H3 | 109 (2) |
O1—C2—C3 | 112.0 (2) | H2—B1—H3 | 107 (2) |
O1i—Na1—O1—C2 | −136.89 (16) | Na1—O1—C2—C3 | −52.8 (2) |
O1i—Na1—O1—B1 | 96.32 (16) | B1—O1—C2—C1 | −172.1 (2) |
O1i—Na1—O1—Na1i | 0.0 | Na1i—O1—C2—C1 | −49.8 (3) |
B1—O1—C2—C3 | 64.8 (3) | Na1—O1—C2—C1 | 70.3 (2) |
Na1i—O1—C2—C3 | −172.85 (16) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) x−1/2, −y+1/2, −z+1; (iv) x+1/2, −y+1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Na(C3H10BO)] |
Mr | 95.91 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 173 |
a, b, c (Å) | 5.5071 (11), 11.094 (2), 19.438 (4) |
V (Å3) | 1187.6 (4) |
Z | 8 |
Radiation type | Cu Kα |
µ (mm−1) | 1.19 |
Crystal size (mm) | 0.5 × 0.05 × 0.02 |
Data collection | |
Diffractometer | Rigaku Spider diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.492, 1.0 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9917, 1119, 849 |
Rint | 0.104 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.070, 0.194, 1.08 |
No. of reflections | 1119 |
No. of parameters | 85 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.49, −0.35 |
Computer programs: CrystalClear (Rigaku, 2005), FSProcess in Process-Auto (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), ORTEP in WinGX (Farrugia, 1999), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
Na1—O1i | 2.3393 (19) | Na1—H3iii | 2.22 (3) |
Na1—O1 | 2.3416 (17) | O1—B1 | 1.486 (3) |
Na1—H2ii | 2.28 (3) | C1—C2 | 1.517 (4) |
O1i—Na1—O1 | 90.38 (6) | H2ii—Na1—H3iii | 97.8 (11) |
O1—Na1—H2ii | 104.5 (8) | Na1i—O1—Na1 | 89.62 (6) |
O1—Na1—H3iii | 133.6 (7) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) x−1/2, −y+1/2, −z+1. |
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This study is part of a programme aimed at investigating boron diolates and alkoxides with potential applications in hydrogen storage/recycling systems (Kemmitt & Gainsford, 2009; Gainsford & Kemmitt, 2005). There are no previous reports of boron trihydride (BH3) structures where the boron is bonded to oxygen, although there are 113 compounds containing C—BH3 (principally cyano-boranes) and 186 reports of N—BH3 adducts [Cambridge Structural Database (CSD); Version 5.30 with February 2009 updates; Allen, 2002]. Likewise, BH3 units bound to P are common (324 hits), whilst the S—BH3 entity is only found three times.
The asymmetric unit contents of the title compound, with formula [Na(C3H10BO)], (I), are shown in Fig. 1. The polymeric unit is built around a highly distorted tetrahedral arrangement of the sodium cations through bridging O atoms (Table 1 and Fig. 2) and adjacent BH3 hydride atoms. The mean Na···O and Na···H distances are 2.3405 (15) and 2.25 (2) Å, with angles subtended at the Na atoms ranging from 97.8 (11) to 133.6 (7)° (Fig. 2). Bridging hydrides (B—H···A) (where A is an alkali metal) are well known in tetrahydroborates (Ruiz et al., 2008). The Na···H distance parameters in (I) are within the ranges noted by Ruiz et al. (2008) {e.g. CSD refcodes HIWXUH [2.28 (2) Å] and HIWZOD (2.32–2.39 Å)} and in the singly-bound Na···H contact in WOCMAD (2.38 Å; Wagler & Hill, 2008). In sodium salts of boron trihydride compounds containing S—B and P—B bonds, the Na···H single contacts are similar at 2.35 (LATSAA; Binder et al., 1993) and 2.32 Å (YILJOT; Izod et al., 2007). The B—O—C angle, and B—O, O—C and Na···O distances, are within the ranges noted previously (Gainsford & Kemmitt, 2004) (XEPPIUE; Knizek et al., 2006).
The unique polymeric structure can be described as layers, running parallel to the ab plane, generated by the 4-coordinated Na, B and O atoms, based on the centrosymmetically related B and O atoms (Figs. 2 and 3) and linked through two of the BH3 hydride atoms. These rings can be delineated as R23(8) rings, taking the BH3 H atoms as donors (Bernstein et al., 1995). This arrangement with sodium ions and BH3 substituents appears unique, with all other reported structures involving tetrahydroborates. The aliphatic isopropyl groups act as spacer units along the c axis (Fig. 3), being involved only in van der Waals interactions.
The B···Na distances average 2.904 (2) Å, consistent with the general observation that such longer interactions indicate less bridging of multiple metal atoms by the hydride atoms (Ruiz et al., 2008). This first reported example of a compound containing the O—BH3 group adds a new dimension to the prolific chemistry of boron hydrides.