Di­methyl­ammonium tetra­hydro­pentaborate

Baber, R.A.; Charmant, J.P.H.; Norman, N.C.; Orpen, A.G.; Rossi, J.

doi:10.1107/S1600536804012371

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 60| Part 6| June 2004| Pages o1086-o1088

https://doi.org/10.1107/S1600536804012371

Dimethylammonium tetrahydropentaborate

R. Angharad Baber,^a Jonathan P. H. Charmant,^a ^* Nicholas C. Norman,^a A. Guy Orpen ^a and Jean Rossi ^a

^aSchool of Chemistry, University of Bristol, Bristol BS8 1TS, England
^*Correspondence e-mail: jon.charmant@bris.ac.uk

(Received 19 May 2004; accepted 20 May 2004; online 29 May 2004)

The title compound [systematic name: dimethylammonium 1,1′-spiro-bis(3,5,-dihydroxy-2,4,6-trioxa-1,3,5-triboracyclohexane)borate], C₂H₈N⁺·B₅H₄O₁₀⁻, contains the [B₅O₆(OH)₄]⁻ tetrahydropentaborate anion, which possesses typical geometrical parameters, accompanied by dimethylammonium cations. The packing of these species is influenced by cation-to-anion N—H⋯O and anion-to-anion O—H⋯O hydrogen bonds.

Comment

The tetrahydropentaborate anion, [B₅O₆(OH)₄]⁻, has been crystallized with a variety of ammonium cations: [NH₄]⁺ (Loboda et al., 1993 ); [H₂NC₅H₁₀]⁺, [NMe₄]⁺ and [NEt₄]⁺ (Wiebcke et al., 1993 ); [HNEt₃]⁺ (Loboda et al., 1994 ); [HNBuⁿ₃]⁺ (Turdybekov et al., 1992 ) and [NPrⁿ₄]⁺ (Freyhardt et al., 1994 ). In this paper, we report the crystal structure of a dimethylammonium salt of this anion, [H₂NMe₂]⁺[B₅O₆(OH)₄]⁻, (I) (Fig. 1).

The anion consists of a central BO₄ tetrahedron fused to four trigonal planar BO₂(OH) units and shows normal geometrical parameters (Table 1). Hydrogen bonding (Table 2) between adjacent [B₅O₆(OH)₄]⁻ units results in R₂²(8) (Etter, 1990 ) dimers (Fig. 2). This anion-to-anion hydrogen-bonding framework is supplemented by the formation of two hydrogen bonds from each dimethylammonium cation to two adjacent [B₅O₆(OH)₄]⁻ anions.

Figure 1
The molecular structure of (I

), showing the atom labelling scheme (50% displacement ellipsoids).

Figure 2
Detail of (I

) in stick representation (key: B pink, O red and H white) illustrating the dimeric R₂²(8) hydrogen-bonding motif linking adjacent [B₅O₆(OH)₄]⁻ anions.

Experimental

A large excess of B(OH)₃ (55.6 mmol, 3.44 g, dried by the Dean–Stark method) was added to a stirred solution of B₂(NMe₂)₄ (1 ml, 5.56 mmol) in tetrahydrofuran (25 ml), and the solution left to stir overnight. After removal of the solvent in vacuo, a white solid remained, which was shown to contain some B₂(OH)₄ and a majority of B(OH)₃ by ¹¹B{¹H} NMR spectroscopy. Dissolution of this solid in degassed water followed by slow evaporation over several days afforded a small crop of thin needle-like crystals approximately 5 mm long, a fragment of one of which was shown to be [H₂NMe₂][B₅O₆(OH)₄].

Crystal data

C₂H₈N⁺·B₅H₄O₁₀⁻
M_r = 264.18
Monoclinic, C2/c
a = 13.3664 (3) Å
b = 11.4709 (3) Å
c = 17.1147 (4) Å
β = 112.160 (1)°
V = 2430.27 (10) Å³
Z = 8
D_x = 1.444 Mg m⁻³
Cu Kα radiation
Cell parameters from 4393 reflections
θ = 5.3–70.2°
μ = 1.19 mm⁻¹
T = 100 (2) K
Block, colourless
0.18 × 0.10 × 0.10 mm

Data collection

Bruker Proteum CCD area-detector diffractometer
ω scans
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.792, T_max = 0.886
9127 measured reflections
2225 independent reflections
1847 reflections with I > 2σ(I)
R_int = 0.026
θ_max = 70.2°
h = −15 → 16
k = −13 → 13
l = −20 → 20

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.088
S = 0.99
2225 reflections
177 parameters
H atoms treated by a mixture of independent and constrained refinement
w = 1/[σ²(F_o²) + (0.0624P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.001
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

B1—O1	1.4623 (16)
B1—O6	1.4679 (16)
B1—O10	1.4680 (16)
B1—O5	1.4726 (18)
B2—O2	1.3506 (18)
B2—O1	1.3628 (18)
B2—O3	1.3860 (18)
B3—O5	1.3571 (18)
B3—O4	1.3612 (18)
B3—O3	1.3849 (17)
B4—O6	1.3530 (18)
B4—O7	1.3550 (17)
B4—O8	1.3843 (17)
B5—O9	1.3522 (17)
B5—O10	1.3643 (18)
B5—O8	1.3813 (17)

B3—O3—B2	118.78 (11)
B3—O5—B1	123.11 (10)
B4—O6—B1	123.62 (10)
B5—O8—B4	119.22 (11)
B5—O10—B1	123.93 (10)

Table 2
Hydrogen-bonding geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1ⁱ	0.92	1.86	2.7707 (15)	170
N1—H1B⋯O4ⁱⁱ	0.92	1.96	2.8765 (15)	173
O2—H2A⋯O7ⁱⁱⁱ	0.848 (17)	1.852 (17)	2.6972 (15)	175.1 (16)
O4—H4A⋯O5^iv	0.814 (16)	1.926 (16)	2.7340 (12)	171.6 (17)
O7—H7A⋯O10^v	0.841 (19)	1.862 (18)	2.7015 (13)	175.8 (18)
O9—H9A⋯O6^vi	0.822 (18)	1.942 (18)	2.7526 (13)	168.8 (19)
Symmetry codes: (i) $[1-x,y-1,{\script{1\over 2}}-z]$ ; (ii) $[x-1,1-y,z-{\script{1\over 2}}]$ ; (iii) $[{\script{1\over 2}}+x,{\script{3\over 2}}-y,{\script{1\over 2}}+z]$ ; (iv) $[2-x,y,{\script{1\over 2}}-z]$ ; (v) $[{\script{3\over 2}}-x,y-{\script{1\over 2}},{\script{1\over 2}}-z]$ ; (vi) $[{\script{3\over 2}}-x,{\script{1\over 2}}+y,{\script{1\over 2}}-z]$ .

The methyl H atoms of the cation were located using a rotating group refinement, with C—H bond lengths constrained to 0.96 Å and displacement parameters equal to 1.5 times U_eq of their parent C atom. The remaining H atoms of the cation were constrained to ideal geometries (Table 2) and refined with displacement parameters equal to 1.2 times U_eq(N). All hydroxyl H atoms were located in Fourier difference maps, assigned displacement parameters equal to 1.5U_eq(O) and refined with a distance restraint of 0.84 (3) Å on the O—H bonds.

Data collection: SMART (Bruker, 2002 ); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT and SHELXTL (Bruker, 2002); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536804012371/hb6049sup1.cif

Structure factors: contains datablock final. DOI: https://doi.org/10.1107/S1600536804012371/hb6049Isup2.hkl

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SHELXTL (Bruker, 2002); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

dimethylammonium 1,1'-spiro-bis(3,5,-dihydroxy-2,4,6-trioxa-1,3,5-triboracyclohexane)borate top

Crystal data top

C₂H₈N⁺·B₅H₄O₁₀⁻	F(000) = 1088
M_r = 264.18	D_x = 1.444 Mg m⁻³
Monoclinic, C2/c	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -C 2yc	Cell parameters from 4393 reflections
a = 13.3664 (3) Å	θ = 5.3–70.2°
b = 11.4709 (3) Å	µ = 1.19 mm⁻¹
c = 17.1147 (4) Å	T = 100 K
β = 112.160 (1)°	Block, colourless
V = 2430.27 (10) Å³	0.18 × 0.10 × 0.10 mm
Z = 8

Data collection top

Bruker SMART CCD area-detector diffractometer	2225 independent reflections
Radiation source: MAC Science M06X CE Rotating anode	1847 reflections with I > 2σ(I)
Osmic CMF12-38Cu6 (blue) optics monochromator	R_int = 0.026
Detector resolution: 5.6 pixels mm^-1	θ_max = 70.2°, θ_min = 5.3°
ω scans	h = −15→16
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −13→13
T_min = 0.792, T_max = 0.886	l = −20→20
9127 measured reflections

Refinement top

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)] = 0.034	Hydrogen site location: difmap (O-H) and geom (C-H and N-H)
wR(F²) = 0.088	H atoms treated by a mixture of independent and constrained refinement
S = 0.99	w = 1/[σ²(F_o²) + (0.0624P)²] where P = (F_o² + 2F_c²)/3
2225 reflections	(Δ/σ)_max = 0.001
177 parameters	Δρ_max = 0.25 e Å⁻³
4 restraints	Δρ_min = −0.25 e Å⁻³

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

	x	y	z	U_iso*/U_eq
B1	0.81860 (12)	0.90832 (12)	0.31606 (9)	0.0166 (3)
B2	0.93003 (12)	0.87280 (12)	0.46759 (9)	0.0180 (3)
B3	1.01942 (12)	0.89925 (12)	0.37177 (9)	0.0181 (3)
B4	0.66922 (12)	0.80519 (13)	0.20378 (9)	0.0204 (3)
B5	0.65759 (12)	1.01176 (13)	0.21409 (9)	0.0197 (3)
O1	0.83319 (7)	0.89692 (7)	0.40480 (5)	0.0176 (2)
O2	0.93013 (8)	0.85132 (8)	0.54521 (6)	0.0224 (2)
H2A	0.9918 (12)	0.8304 (16)	0.5797 (10)	0.034*
O3	1.02458 (7)	0.87224 (8)	0.45206 (5)	0.0195 (2)
O4	1.11499 (7)	0.90211 (8)	0.36063 (6)	0.0221 (2)
H4A	1.1035 (15)	0.9148 (15)	0.3112 (10)	0.033*
O5	0.92372 (7)	0.92038 (7)	0.30757 (5)	0.0177 (2)
O6	0.76559 (7)	0.80361 (7)	0.26945 (5)	0.0180 (2)
O7	0.62507 (8)	0.70632 (8)	0.16148 (6)	0.0300 (3)
H7A	0.6629 (15)	0.6470 (15)	0.1818 (12)	0.045*
O8	0.61277 (8)	0.90800 (8)	0.17587 (6)	0.0261 (2)
O9	0.60298 (8)	1.11071 (8)	0.18115 (6)	0.0257 (2)
H9A	0.6414 (14)	1.1673 (15)	0.2022 (12)	0.039*
O10	0.75402 (7)	1.01298 (7)	0.28109 (5)	0.0178 (2)
N1	0.28012 (9)	0.01583 (10)	0.01395 (7)	0.0234 (3)
H1A	0.2448	−0.0171	0.0454	0.028*
H1B	0.2287	0.0366	−0.0374	0.028*
C1	0.33666 (14)	0.12213 (15)	0.05735 (11)	0.0417 (4)
H1C	0.2854	0.1734	0.0691	0.063*
H1D	0.3672	0.1630	0.0212	0.063*
H1E	0.3949	0.1004	0.1105	0.063*
C2	0.35208 (15)	−0.07212 (17)	0.00023 (11)	0.0435 (4)
H2B	0.3096	−0.1404	−0.0278	0.065*
H2C	0.4067	−0.0955	0.0547	0.065*
H2D	0.3878	−0.0390	−0.0353	0.065*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
B1	0.0141 (7)	0.0157 (7)	0.0165 (7)	−0.0001 (5)	0.0018 (6)	0.0000 (5)
B2	0.0174 (7)	0.0131 (7)	0.0195 (7)	−0.0003 (5)	0.0025 (6)	−0.0016 (5)
B3	0.0167 (7)	0.0158 (7)	0.0184 (7)	−0.0003 (5)	0.0027 (6)	−0.0027 (5)
B4	0.0177 (7)	0.0193 (8)	0.0186 (7)	−0.0003 (6)	0.0006 (6)	0.0002 (5)
B5	0.0157 (7)	0.0190 (8)	0.0209 (8)	0.0000 (6)	0.0029 (6)	0.0001 (5)
O1	0.0135 (4)	0.0203 (5)	0.0159 (5)	0.0004 (3)	0.0020 (4)	−0.0002 (3)
O2	0.0174 (5)	0.0275 (6)	0.0180 (5)	0.0019 (4)	0.0018 (4)	0.0037 (4)
O3	0.0137 (4)	0.0233 (5)	0.0173 (5)	0.0018 (4)	0.0011 (4)	0.0010 (3)
O4	0.0148 (5)	0.0319 (6)	0.0164 (5)	0.0005 (4)	0.0024 (4)	−0.0010 (4)
O5	0.0140 (4)	0.0201 (5)	0.0161 (5)	0.0001 (3)	0.0023 (4)	0.0003 (3)
O6	0.0154 (5)	0.0152 (5)	0.0189 (5)	0.0010 (3)	0.0012 (4)	−0.0004 (3)
O7	0.0257 (5)	0.0164 (5)	0.0301 (6)	0.0026 (4)	−0.0097 (4)	−0.0019 (4)
O8	0.0194 (5)	0.0176 (5)	0.0268 (5)	0.0004 (4)	−0.0077 (4)	−0.0003 (4)
O9	0.0189 (5)	0.0165 (5)	0.0290 (5)	−0.0001 (4)	−0.0055 (4)	0.0003 (4)
O10	0.0149 (4)	0.0155 (5)	0.0181 (5)	0.0001 (3)	0.0006 (4)	−0.0004 (3)
N1	0.0162 (5)	0.0291 (6)	0.0211 (6)	−0.0007 (5)	0.0026 (5)	0.0052 (4)
C1	0.0343 (9)	0.0355 (9)	0.0417 (10)	−0.0121 (7)	−0.0011 (8)	0.0030 (7)
C2	0.0373 (9)	0.0534 (12)	0.0407 (10)	0.0168 (8)	0.0158 (8)	0.0065 (7)

Geometric parameters (Å, º) top

B1—O1	1.4623 (16)	B5—O8	1.3813 (17)
B1—O6	1.4679 (16)	O2—H2A	0.848 (14)
B1—O10	1.4680 (16)	O4—H4A	0.814 (14)
B1—O5	1.4726 (18)	O7—H7A	0.841 (15)
B2—O2	1.3506 (18)	O9—H9A	0.822 (15)
B2—O1	1.3628 (18)	N1—C2	1.473 (2)
B2—O3	1.3860 (18)	N1—C1	1.479 (2)
B3—O5	1.3571 (18)	N1—H1A	0.9200
B3—O4	1.3612 (18)	N1—H1B	0.9200
B3—O3	1.3849 (17)	C1—H1C	0.9800
B4—O6	1.3530 (18)	C1—H1D	0.9800
B4—O7	1.3550 (17)	C1—H1E	0.9800
B4—O8	1.3843 (17)	C2—H2B	0.9800
B5—O9	1.3522 (17)	C2—H2C	0.9800
B5—O10	1.3643 (18)	C2—H2D	0.9800

O1—B1—O6	109.83 (10)	B4—O6—B1	123.62 (10)
O1—B1—O10	108.91 (10)	B4—O7—H7A	112.5 (14)
O6—B1—O10	111.01 (10)	B5—O8—B4	119.22 (11)
O1—B1—O5	110.64 (10)	B5—O9—H9A	109.3 (14)
O6—B1—O5	107.83 (10)	B5—O10—B1	123.93 (10)
O10—B1—O5	108.62 (10)	C2—N1—C1	113.84 (13)
O2—B2—O1	117.44 (13)	C2—N1—H1A	108.8
O2—B2—O3	121.67 (12)	C1—N1—H1A	108.8
O1—B2—O3	120.89 (12)	C2—N1—H1B	108.8
O5—B3—O4	122.01 (12)	C1—N1—H1B	108.8
O5—B3—O3	121.49 (13)	H1A—N1—H1B	107.7
O4—B3—O3	116.50 (12)	N1—C1—H1C	109.5
O6—B4—O7	121.26 (12)	N1—C1—H1D	109.5
O6—B4—O8	121.48 (12)	H1C—C1—H1D	109.5
O7—B4—O8	117.24 (12)	N1—C1—H1E	109.5
O9—B5—O10	122.15 (12)	H1C—C1—H1E	109.5
O9—B5—O8	117.16 (12)	H1D—C1—H1E	109.5
O10—B5—O8	120.69 (12)	N1—C2—H2B	109.5
B2—O1—B1	123.50 (11)	N1—C2—H2C	109.5
B2—O2—H2A	112.2 (12)	H2B—C2—H2C	109.5
B3—O3—B2	118.78 (11)	N1—C2—H2D	109.5
B3—O4—H4A	109.3 (14)	H2B—C2—H2D	109.5
B3—O5—B1	123.11 (10)	H2C—C2—H2D	109.5

O2—B2—O1—B1	−172.54 (11)	O7—B4—O6—B1	178.29 (12)
O3—B2—O1—B1	8.38 (19)	O8—B4—O6—B1	−0.3 (2)
O6—B1—O1—B2	104.43 (13)	O1—B1—O6—B4	119.72 (13)
O10—B1—O1—B2	−133.81 (11)	O10—B1—O6—B4	−0.78 (17)
O5—B1—O1—B2	−14.49 (16)	O5—B1—O6—B4	−119.64 (13)
O5—B3—O3—B2	−3.31 (18)	O9—B5—O8—B4	175.72 (13)
O4—B3—O3—B2	177.43 (11)	O10—B5—O8—B4	−3.0 (2)
O2—B2—O3—B3	−177.60 (12)	O6—B4—O8—B5	2.2 (2)
O1—B2—O3—B3	1.43 (19)	O7—B4—O8—B5	−176.43 (13)
O4—B3—O5—B1	174.74 (11)	O9—B5—O10—B1	−176.76 (12)
O3—B3—O5—B1	−4.48 (19)	O8—B5—O10—B1	1.9 (2)
O1—B1—O5—B3	12.53 (16)	O1—B1—O10—B5	−121.03 (13)
O6—B1—O5—B3	−107.59 (12)	O6—B1—O10—B5	0.01 (17)
O10—B1—O5—B3	132.03 (11)	O5—B1—O10—B5	118.39 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.92	1.86	2.7707 (15)	170
N1—H1B···O4ⁱⁱ	0.92	1.96	2.8765 (15)	173
O2—H2A···O7ⁱⁱⁱ	0.85 (2)	1.85 (2)	2.6972 (15)	175 (2)
O4—H4A···O5^iv	0.81 (2)	1.93 (2)	2.7340 (12)	172 (2)
O7—H7A···O10^v	0.84 (2)	1.86 (2)	2.7015 (13)	176 (2)
O9—H9A···O6^vi	0.82 (2)	1.94 (2)	2.7526 (13)	169 (2)

Symmetry codes: (i) −x+1, y−1, −z+1/2; (ii) x−1, −y+1, z−1/2; (iii) x+1/2, −y+3/2, z+1/2; (iv) −x+2, y, −z+1/2; (v) −x+3/2, y−1/2, −z+1/2; (vi) −x+3/2, y+1/2, −z+1/2.

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