Acta Cryst. (2008). E64, o583 [ doi:10.1107/S1600536808003589 ]
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N)boron(III) chlorideThe title compound, C2H10BCl2N2+·Cl- or [BCl2(H3CNH2)2]+·Cl-, is the first crystallographically characterized di(alkylamine)-BCl2+ salt. The B atom is tetrahedrally coordinated by two Cl and two methylamine N atoms. In the crystal structure, the cations and anions interact via N-H
Cl hydrogen bonds (mean HCl = 2.40 Å), resulting in a layered structure.
[BCl2(H3CNH2)2]Cl was obtained as a side-product in amounts < 5% during the continuous synthesis of DMTA. Details of the experimental setup are found elsewhere (Weinmann, Nuss et al., 2007; Weinmann, Kroschel et al., 2007). Re-crystallization of the reaction mixture from THF/n-hexane afforded colourless needles of (I).
All H atoms were found in a difference map and their positions and Uiso values were freely refined.
Data collection: SMART (Bruker 2005); cell refinement: SAINT (Bruker 2005); data reduction: SAINT (Bruker 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS (Dowty, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./hb2697fig1thm.gif)
| Fig. 1. Molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level (arbitrary spheres for the H atoms). Hydrogen bonds are indicated by thin red lines. |
![[Figure 2]](./hb2697fig2thm.gif)
| Fig. 2. Packing diagram of (I) with hydrogen bonds indicated by dashed lines. |
| C2H10BCl2N2+·Cl– | F000 = 736 |
| Mr = 179.28 | Dx = 1.432 Mg m−3 |
| Orthorhombic, Pbca | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2ac 2ab | Cell parameters from 5369 reflections |
| a = 9.9881 (11) Å | θ = 2.6–34.8º |
| b = 11.8071 (13) Å | µ = 1.01 mm−1 |
| c = 14.1039 (15) Å | T = 100 (2) K |
| V = 1663.3 (3) Å3 | Needle, colourless |
| Z = 8 | 0.30 × 0.02 × 0.02 mm |
| Bruker SMART APEX diffractometer | 2430 independent reflections |
| Radiation source: fine-focus sealed tube | 2123 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.050 |
| T = 100(2) K | θmax = 30.0º |
| ω scans | θmin = 2.9º |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −14→14 |
| Tmin = 0.751, Tmax = 0.980 | k = −16→16 |
| 19044 measured reflections | l = −19→19 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.043 | All H-atom parameters refined |
| wR(F2) = 0.089 | w = 1/[σ2(Fo2) + (0.036P)2 + 0.6817P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.22 | (Δ/σ)max = 0.001 |
| 2430 reflections | Δρmax = 0.62 e Å−3 |
| 113 parameters | Δρmin = −0.28 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C2H10BCl2N2+·Cl– | V = 1663.3 (3) Å3 |
| Mr = 179.28 | Z = 8 |
| Orthorhombic, Pbca | Mo Kα |
| a = 9.9881 (11) Å | µ = 1.01 mm−1 |
| b = 11.8071 (13) Å | T = 100 (2) K |
| c = 14.1039 (15) Å | 0.30 × 0.02 × 0.02 mm |
| Bruker SMART APEX diffractometer | 2430 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | 2123 reflections with I > 2σ(I) |
| Tmin = 0.751, Tmax = 0.980 | Rint = 0.050 |
| 19044 measured reflections |
| R[F2 > 2σ(F2)] = 0.043 | 113 parameters |
| wR(F2) = 0.089 | All H-atom parameters refined |
| S = 1.22 | Δρmax = 0.62 e Å−3 |
| 2430 reflections | Δρmin = −0.28 e Å−3 |
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 | ||
| Cl1 | 0.43797 (5) | 0.04596 (4) | 0.73581 (4) | 0.02091 (13) | |
| Cl2 | 0.54279 (5) | −0.21105 (4) | 0.55584 (3) | 0.01808 (12) | |
| Cl3 | 0.82564 (5) | −0.25006 (4) | 0.63429 (4) | 0.01710 (12) | |
| B | 0.6695 (2) | −0.16781 (17) | 0.64305 (15) | 0.0120 (4) | |
| N1 | 0.70412 (17) | −0.03969 (14) | 0.62830 (12) | 0.0136 (3) | |
| H1A | 0.630 (3) | −0.002 (2) | 0.6429 (17) | 0.021 (6)* | |
| H1B | 0.767 (3) | −0.023 (2) | 0.6669 (19) | 0.024 (7)* | |
| N2 | 0.60546 (17) | −0.18659 (14) | 0.74288 (12) | 0.0137 (3) | |
| H2A | 0.535 (3) | −0.145 (2) | 0.7468 (19) | 0.030 (7)* | |
| H2B | 0.579 (3) | −0.256 (3) | 0.744 (2) | 0.028 (7)* | |
| C3 | 0.7536 (3) | −0.01034 (19) | 0.53109 (16) | 0.0212 (4) | |
| H3A | 0.831 (3) | −0.059 (2) | 0.519 (2) | 0.032 (7)* | |
| H3B | 0.682 (3) | −0.020 (3) | 0.488 (2) | 0.040 (8)* | |
| H3C | 0.782 (3) | 0.066 (2) | 0.5310 (19) | 0.027 (7)* | |
| C4 | 0.6894 (3) | −0.1676 (2) | 0.82892 (16) | 0.0253 (5) | |
| H4A | 0.636 (3) | −0.178 (2) | 0.8830 (19) | 0.025 (7)* | |
| H4B | 0.766 (4) | −0.218 (3) | 0.831 (2) | 0.045 (9)* | |
| H4C | 0.724 (3) | −0.094 (3) | 0.825 (2) | 0.034 (8)* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl1 | 0.0190 (2) | 0.0103 (2) | 0.0334 (3) | 0.00027 (17) | 0.0106 (2) | −0.00070 (18) |
| Cl2 | 0.0168 (2) | 0.0200 (2) | 0.0174 (2) | −0.00113 (18) | −0.00353 (18) | −0.00502 (18) |
| Cl3 | 0.0131 (2) | 0.0133 (2) | 0.0249 (3) | 0.00233 (17) | 0.00170 (18) | −0.00173 (18) |
| B | 0.0121 (9) | 0.0100 (9) | 0.0140 (10) | −0.0011 (7) | 0.0011 (7) | 0.0001 (7) |
| N1 | 0.0143 (8) | 0.0125 (8) | 0.0141 (8) | −0.0001 (6) | 0.0007 (6) | −0.0001 (6) |
| N2 | 0.0144 (8) | 0.0105 (7) | 0.0161 (8) | −0.0011 (6) | 0.0004 (6) | −0.0003 (6) |
| C3 | 0.0308 (12) | 0.0155 (10) | 0.0173 (10) | −0.0007 (9) | 0.0065 (9) | 0.0034 (8) |
| C4 | 0.0299 (12) | 0.0321 (13) | 0.0140 (10) | −0.0132 (10) | −0.0023 (9) | 0.0022 (9) |
| B—Cl2 | 1.837 (2) | N2—H2A | 0.86 (3) |
| B—Cl3 | 1.841 (2) | N2—H2B | 0.86 (3) |
| B—N2 | 1.562 (3) | C3—H3A | 0.98 (3) |
| B—N1 | 1.566 (3) | C3—H3B | 0.95 (3) |
| N1—C3 | 1.498 (3) | C3—H3C | 0.95 (3) |
| N1—H1A | 0.89 (3) | C4—H4A | 0.94 (3) |
| N1—H1B | 0.85 (3) | C4—H4B | 0.97 (3) |
| N2—C4 | 1.492 (3) | C4—H4C | 0.93 (3) |
| N2—B—N1 | 110.33 (15) | C4—N2—H2B | 107.4 (18) |
| N2—B—Cl2 | 106.38 (13) | B—N2—H2B | 106.0 (18) |
| N1—B—Cl2 | 109.37 (13) | H2A—N2—H2B | 107 (3) |
| N2—B—Cl3 | 109.41 (13) | N1—C3—H3A | 106.6 (16) |
| N1—B—Cl3 | 108.27 (13) | N1—C3—H3B | 108.3 (18) |
| Cl2—B—Cl3 | 113.08 (11) | H3A—C3—H3B | 114 (2) |
| C3—N1—B | 114.71 (16) | N1—C3—H3C | 108.7 (16) |
| C3—N1—H1A | 111.9 (16) | H3A—C3—H3C | 109 (2) |
| B—N1—H1A | 105.4 (17) | H3B—C3—H3C | 110 (2) |
| C3—N1—H1B | 106.6 (18) | N2—C4—H4A | 108.8 (17) |
| B—N1—H1B | 107.7 (18) | N2—C4—H4B | 112.0 (19) |
| H1A—N1—H1B | 110 (2) | H4A—C4—H4B | 110 (3) |
| C4—N2—B | 118.80 (16) | N2—C4—H4C | 107.7 (18) |
| C4—N2—H2A | 108.7 (18) | H4A—C4—H4C | 112 (2) |
| B—N2—H2A | 108.1 (18) | H4B—C4—H4C | 106 (3) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···Cl1 | 0.89 (3) | 2.39 (3) | 3.2232 (18) | 156 (2) |
| N1—H1B···Cl1i | 0.85 (3) | 2.34 (3) | 3.1862 (18) | 173 (2) |
| N2—H2A···Cl1 | 0.86 (3) | 2.46 (3) | 3.2168 (18) | 148 (2) |
| N2—H2B···Cl1ii | 0.86 (3) | 2.36 (3) | 3.2016 (18) | 165 (2) |
| Symmetry codes: (i) x+1/2, y, −z+3/2; (ii) −x+1, y−1/2, −z+3/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···Cl1 | 0.89 (3) | 2.39 (3) | 3.2232 (18) | 156 (2) |
| N1—H1B···Cl1i | 0.85 (3) | 2.34 (3) | 3.1862 (18) | 173 (2) |
| N2—H2A···Cl1 | 0.86 (3) | 2.46 (3) | 3.2168 (18) | 148 (2) |
| N2—H2B···Cl1ii | 0.86 (3) | 2.36 (3) | 3.2016 (18) | 165 (2) |
| Symmetry codes: (i) x+1/2, y, −z+3/2; (ii) −x+1, y−1/2, −z+3/2. |
The authors acknowledge financial support by the Max-Planck-Society and the German Research Foundation.
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Borazonium cations BCl2+ coordinated by secondary amines R2NH are very few in number whereas those coordinated by primary amines are more or less unknown. To our knowledge, there has appeared so far no publication dealing with H3CNH2-coordinated BCl2+ cations.
We recently published the continuous synthesis of Cl3Si-NCH3—BCl2 (DMTA) by a two-step gas phase synthesis. This reaction proceeds with the formation of solid by-products which are separated from the desired product by filtration. The solid mainly consists of MeNH3Cl. Moreover we observed formation of crystalline 2,4,6-trichloro-1,3,5-trimethylborazine, (CH3NBCl)3 (Weinmann, Nuss et al., 2007). Re-crystallization of the solid from THF/n-pentane now additionally afforded crystals of the title compound, (I) (Fig. 1).
The boron atom in the BCl2L2+ cation in (I) is tetrahedrally coordinated by two chlorine atoms Cl2 and Cl3 and two nitrogen atoms N1 and N2 of the methylamine ligands. The smallest angle (N2—B—Cl2) measures 106.38 (13)°, while the biggest (Cl2—B—Cl3) amounts to 113.08 (11)°. The B—Cl bond distances are 1.837 (2) and 1.841 (2) Å whereas the B—N bond lengths measure 1.566 (3) and 1.562 (3) Å. These are values typically found in tetrachloroborate (BCl4-) or tetraaminoborate (B(NR2)4-) anions, respectively.
The chloride counter anions are associated with the cations via N—H···Cl hydrogen bonds (Table 1). From Figure 2 it is evident that the anions are each connetcted to four hydrogen atoms, thereby linking three cations. Consequently all the N-bonded H atoms contribute to hydrogen-bond bridges.
A further special feature is the formation of a layered structure in (001) which results from the H-bridge formation. The layers, which are stacked in [001] are connected via less polar van-der-Vaals interactions.