(S)-Alanine ethyl ester tetra­cyanidoborate, (C₅H₁₂NO)[B(CN)₄]

The title mol­ecular salt, C₅H₁₂NO⁺·C₄BN₄⁻ or (C₅H₁₂NO)[B(CN)₄], was obtained as single crystals by slow evaporation of a solution of the compound in aceto­nitrile over several weeks. The asymmetric unit contains two (S)-alanine ethyl ester cations and two tetra­cyanidoborate anions, which are linked by N—H...N hydrogen bonds. The compound exhibits a relatively low melting point of 110°C and shows a solid–solid phase transition near room temperature (T_s–s = 29°C) on the basis of DSC measurements.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.053
• wR factor = 0.133
• Data-to-parameter ratio = 24.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT910_ALERT_3_B Missing # of FCF Reflection(s) Below Theta(Min).         16 Note

Alert level C
STRVA01_ALERT_4_C           Flack test results are meaningless.
           From the CIF: _refine_ls_abs_structure_Flack    0.200
           From the CIF: _refine_ls_abs_structure_Flack_su    0.800
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.1 Note
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.4 Note
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds ...............    0.00467 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H9F      ..N3       .       2.64 Ang.
PLAT911_ALERT_3_C Missing FCF Refl Between Thmin & STh/L=    0.600         10 Report
PLAT915_ALERT_3_C No Flack x Check Done: Low Friedel Pair Coverage         78 %
PLAT978_ALERT_2_C Number C-C Bonds with Positive Residual Density.          0 Info

Alert level G
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............          6 Report
PLAT032_ALERT_4_G Std. Uncertainty on Flack Parameter Value High .      0.800 Report
PLAT042_ALERT_1_G Calc. and Reported Moiety Formula Strings Differ     Please Check
PLAT791_ALERT_4_G Model has Chirality at C10         (Sohnke SpGr)          S Verify
PLAT791_ALERT_4_G Model has Chirality at C15         (Sohnke SpGr)          S Verify
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600        105 Note
PLAT916_ALERT_2_G Hooft y and Flack x Parameter Values Differ by .       0.33 Check
PLAT933_ALERT_2_G Number of OMIT Records in Embedded .res File ...         32 Note

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 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
   6 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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Computing details

Data collection: APEX2 (Bruker, 2017); cell refinement: SAINT (Bruker, 2017); data reduction: SAINT (Bruker, 2017); program(s) used to solve structure: SHELXS (Sheldrick, 2015b); program(s) used to refine structure: SHELXT (Sheldrick, 2015a); molecular graphics: DIAMOND (Brandenburg & Putz, 2019); software used to prepare material for publication: publCIF (Westrip, 2010).

1-Ethoxy-1-oxopropan-2-aminium tetracyanoborate

Crystal data

C5H12NO2^+·C4N4B^−	F(000) = 976
Mr = 233.05	Dx = 1.182 Mg m^−3
Monoclinic, C2	Mo Kα radiation, λ = 0.71073 Å
a = 17.059 (1) Å	Cell parameters from 2564 reflections
b = 8.7467 (4) Å	θ = 4.3–25.5°
c = 18.855 (1) Å	µ = 0.09 mm^−1
β = 111.468 (4)°	T = 173 K
V = 2618.2 (3) Å^3	Block, colourless
Z = 8	0.27 × 0.18 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer	5158 reflections with I > 2σ(I)
Radiation source: microfocus sealed tube	Rint = 0.038
φ and ω scans	θmax = 31.0°, θmin = 4.4°
Absorption correction: multi-scan (SADABS; Bruker, 2017)	h = −24→24
	k = −10→12
11976 measured reflections	l = −25→26
7354 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.053	H-atom parameters constrained
wR(F^2) = 0.133	w = 1/[σ^2(Fo^2) + (0.0649P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max < 0.001
7354 reflections	Δρmax = 0.38 e Å^−3
307 parameters	Δρmin = −0.24 e Å^−3
1 restraint	Absolute structure: Flack x determined using 1751 quotients [(I^+)-(I^-)]/[(I^+)+(I^-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.2 (8)

Special details

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
B1	0.4401 (2)	0.0236 (3)	0.3575 (2)	0.0267 (6)
C1	0.4986 (2)	0.1670 (3)	0.3916 (2)	0.0327 (6)
N1	0.5418 (2)	0.2686 (3)	0.4167 (2)	0.0494 (7)
C2	0.4971 (2)	−0.1273 (3)	0.3745 (2)	0.0281 (5)
N2	0.5371 (2)	−0.2346 (3)	0.3855 (1)	0.0405 (6)
C3	0.3940 (2)	0.0381 (3)	0.2677 (2)	0.0326 (6)
N3	0.3621 (2)	0.0434 (3)	0.2032 (2)	0.0505 (7)
C4	0.3729 (2)	0.0061 (3)	0.3968 (2)	0.0343 (6)
N4	0.3242 (2)	−0.0082 (4)	0.4246 (2)	0.0524 (7)
B2	0.4421 (2)	0.4179 (3)	0.8626 (2)	0.0288 (6)
C5	0.4893 (2)	0.5759 (3)	0.8893 (2)	0.0378 (6)
N5	0.5235 (2)	0.6898 (3)	0.9064 (2)	0.0574 (8)
C6	0.5081 (2)	0.2830 (3)	0.8927 (2)	0.0345 (6)
N6	0.5555 (2)	0.1866 (3)	0.9158 (2)	0.0505 (7)
C7	0.4013 (2)	0.4174 (4)	0.7723 (2)	0.0396 (7)
N7	0.3728 (2)	0.4224 (4)	0.7078 (2)	0.068 (1)
C8	0.3709 (2)	0.3968 (3)	0.8974 (2)	0.0304 (5)
N8	0.3198 (2)	0.3818 (3)	0.9222 (2)	0.0423 (6)
C9	0.1899 (2)	0.2660 (3)	0.0774 (2)	0.0485 (8)
H9A	0.1933	0.2721	0.1304	0.073*
H9B	0.2436	0.2290	0.0762	0.073*
H9C	0.1447	0.1952	0.0491	0.073*
C10	0.1714 (2)	0.4213 (3)	0.0417 (1)	0.0284 (5)
H10A	0.1168	0.4582	0.0436	0.034*
N9	0.1651 (1)	0.4193 (2)	−0.0392 (1)	0.0251 (4)
H9D	0.1236	0.3536	−0.0663	0.038*
H9E	0.2150	0.3881	−0.0414	0.038*
H9F	0.1529	0.5149	−0.0592	0.038*
C11	0.2398 (2)	0.5319 (3)	0.0848 (1)	0.0290 (5)
O1	0.2858 (1)	0.5932 (2)	0.0589 (1)	0.0390 (5)
O2	0.2429 (1)	0.5455 (2)	0.1560 (1)	0.0417 (5)
C12	0.3156 (2)	0.6236 (4)	0.2100 (2)	0.0534 (9)
H12A	0.3004	0.6699	0.2511	0.064*
H12B	0.3340	0.7064	0.1838	0.064*
C13	0.3855 (2)	0.5119 (6)	0.2431 (2)	0.069 (1)
H13A	0.4347	0.5646	0.2791	0.103*
H13B	0.4003	0.4663	0.2022	0.103*
H13C	0.3674	0.4313	0.2699	0.103*
C14	0.6152 (2)	0.5843 (4)	0.5570 (2)	0.0447 (7)
H14A	0.6329	0.6107	0.6111	0.067*
H14B	0.5816	0.4904	0.5470	0.067*
H14C	0.5813	0.6678	0.5261	0.067*
C15	0.6923 (2)	0.5598 (3)	0.5365 (1)	0.0262 (5)
H15A	0.7255	0.6569	0.5462	0.031*
N10	0.6667 (1)	0.5199 (2)	0.4547 (1)	0.0228 (4)
H10B	0.7135	0.5058	0.4430	0.034*
H10C	0.6352	0.5971	0.4258	0.034*
H10D	0.6358	0.4323	0.4451	0.034*
C16	0.7477 (2)	0.4339 (3)	0.5836 (1)	0.0246 (5)
O3	0.7610 (1)	0.3169 (2)	0.5581 (1)	0.0429 (5)
O4	0.7763 (2)	0.4724 (3)	0.6559 (1)	0.0500 (6)
C17	0.8324 (2)	0.3692 (4)	0.7118 (2)	0.0477 (8)
H17A	0.8557	0.2922	0.6864	0.057*
H17B	0.8015	0.3151	0.7397	0.057*
C18	0.9012 (2)	0.4620 (6)	0.7653 (2)	0.065 (1)
H18A	0.9405	0.3952	0.8037	0.097*
H18B	0.8776	0.5372	0.7904	0.097*
H18C	0.9313	0.5153	0.7371	0.097*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
B1	0.024 (1)	0.028 (1)	0.028 (2)	−0.001 (1)	0.010 (1)	0.001 (1)
C1	0.035 (1)	0.033 (1)	0.030 (1)	−0.001 (1)	0.012 (1)	0.001 (1)
N1	0.057 (2)	0.042 (1)	0.045 (2)	−0.017 (1)	0.014 (1)	−0.006 (1)
C2	0.027 (1)	0.031 (1)	0.029 (1)	−0.001 (1)	0.013 (1)	0.004 (1)
N2	0.038 (1)	0.041 (1)	0.045 (2)	0.007 (1)	0.018 (1)	0.009 (1)
C3	0.032 (1)	0.031 (1)	0.033 (2)	−0.001 (1)	0.010 (1)	0.002 (1)
N3	0.051 (2)	0.060 (2)	0.033 (1)	−0.004 (1)	0.006 (1)	0.003 (1)
C4	0.029 (1)	0.038 (1)	0.037 (2)	0.001 (1)	0.014 (1)	0.000 (1)
N4	0.041 (1)	0.070 (2)	0.055 (2)	0.002 (1)	0.028 (1)	−0.001 (2)
B2	0.028 (1)	0.028 (1)	0.029 (2)	0.004 (1)	0.009 (1)	0.001 (1)
C5	0.027 (1)	0.036 (1)	0.048 (2)	0.002 (1)	0.011 (1)	0.006 (1)
N5	0.039 (1)	0.041 (2)	0.081 (2)	−0.006 (1)	0.009 (1)	0.003 (2)
C6	0.037 (1)	0.035 (1)	0.029 (2)	0.006 (1)	0.010 (1)	−0.002 (1)
N6	0.053 (2)	0.046 (2)	0.043 (2)	0.019 (1)	0.007 (1)	−0.003 (1)
C7	0.040 (2)	0.045 (2)	0.035 (2)	0.010 (1)	0.014 (1)	0.007 (1)
N7	0.070 (2)	0.098 (3)	0.034 (2)	0.023 (2)	0.015 (1)	0.012 (2)
C8	0.029 (1)	0.028 (1)	0.030 (1)	0.002 (1)	0.006 (1)	−0.002 (1)
N8	0.036 (1)	0.047 (1)	0.046 (2)	0.001 (1)	0.019 (1)	0.001 (1)
C9	0.077 (2)	0.033 (2)	0.034 (2)	−0.009 (2)	0.018 (2)	0.002 (1)
C10	0.028 (1)	0.032 (1)	0.026 (1)	−0.002 (1)	0.012 (1)	0.002 (1)
N9	0.026 (1)	0.0231 (9)	0.025 (1)	−0.0002 (8)	0.0083 (8)	−0.0007 (8)
C11	0.035 (1)	0.028 (1)	0.024 (1)	−0.001 (1)	0.011 (1)	0.002 (1)
O1	0.047 (1)	0.041 (1)	0.033 (1)	−0.0185 (9)	0.0192 (9)	−0.0055 (8)
O2	0.054 (1)	0.047 (1)	0.026 (1)	−0.016 (1)	0.0161 (8)	−0.0048 (8)
C12	0.073 (2)	0.056 (2)	0.026 (2)	−0.030 (2)	0.012 (2)	−0.010 (1)
C13	0.054 (2)	0.100 (3)	0.046 (2)	−0.014 (2)	0.010 (2)	−0.022 (2)
C14	0.049 (2)	0.060 (2)	0.030 (1)	0.027 (2)	0.020 (1)	0.009 (1)
C15	0.035 (1)	0.022 (1)	0.021 (1)	0.004 (1)	0.0097 (9)	0.0004 (9)
N10	0.0255 (9)	0.0230 (9)	0.021 (1)	0.0000 (8)	0.0092 (7)	0.0005 (7)
C16	0.025 (1)	0.027 (1)	0.022 (1)	0.0028 (9)	0.0096 (9)	0.0022 (9)
O3	0.059 (1)	0.032 (1)	0.032 (1)	0.0192 (9)	0.0095 (9)	−0.0016 (8)
O4	0.068 (1)	0.049 (1)	0.023 (1)	0.026 (1)	0.0046 (9)	0.0007 (9)
C17	0.052 (2)	0.062 (2)	0.026 (2)	0.027 (2)	0.010 (1)	0.013 (1)
C18	0.041 (2)	0.104 (3)	0.048 (2)	0.015 (2)	0.014 (2)	0.014 (2)

Geometric parameters (Å, º)

B1—C4	1.585 (4)	C11—O2	1.330 (3)
B1—C1	1.585 (4)	O2—C12	1.455 (3)
B1—C3	1.591 (4)	C12—C13	1.490 (6)
B1—C2	1.600 (4)	C12—H12A	0.9900
C1—N1	1.142 (4)	C12—H12B	0.9900
C2—N2	1.135 (3)	C13—H13A	0.9800
C3—N3	1.137 (3)	C13—H13B	0.9800
C4—N4	1.138 (4)	C13—H13C	0.9800
B2—C7	1.585 (4)	C14—C15	1.514 (4)
B2—C6	1.586 (4)	C14—H14A	0.9800
B2—C5	1.586 (4)	C14—H14B	0.9800
B2—C8	1.590 (4)	C14—H14C	0.9800
C5—N5	1.140 (4)	C15—N10	1.482 (3)
C6—N6	1.139 (4)	C15—C16	1.510 (3)
C7—N7	1.134 (4)	C15—H15A	1.0000
C8—N8	1.138 (3)	N10—H10B	0.9100
C9—C10	1.497 (4)	N10—H10C	0.9100
C9—H9A	0.9800	N10—H10D	0.9100
C9—H9B	0.9800	C16—O3	1.188 (3)
C9—H9C	0.9800	C16—O4	1.312 (3)
C10—N9	1.489 (3)	O4—C17	1.451 (3)
C10—C11	1.505 (4)	C17—C18	1.479 (5)
C10—H10A	1.0000	C17—H17A	0.9900
N9—H9D	0.9100	C17—H17B	0.9900
N9—H9E	0.9100	C18—H18A	0.9800
N9—H9F	0.9100	C18—H18B	0.9800
C11—O1	1.192 (3)	C18—H18C	0.9800
C4—B1—C1	110.0 (2)	C13—C12—H12A	109.8
C4—B1—C3	110.2 (2)	O2—C12—H12B	109.8
C1—B1—C3	111.2 (2)	C13—C12—H12B	109.8
C4—B1—C2	108.5 (2)	H12A—C12—H12B	108.2
C1—B1—C2	109.0 (2)	C12—C13—H13A	109.5
C3—B1—C2	107.8 (2)	C12—C13—H13B	109.5
N1—C1—B1	178.8 (3)	H13A—C13—H13B	109.5
N2—C2—B1	179.0 (3)	C12—C13—H13C	109.5
N3—C3—B1	177.5 (3)	H13A—C13—H13C	109.5
N4—C4—B1	179.1 (3)	H13B—C13—H13C	109.5
C7—B2—C6	111.0 (2)	C15—C14—H14A	109.5
C7—B2—C5	108.4 (2)	C15—C14—H14B	109.5
C6—B2—C5	108.9 (2)	H14A—C14—H14B	109.5
C7—B2—C8	110.0 (2)	C15—C14—H14C	109.5
C6—B2—C8	108.3 (2)	H14A—C14—H14C	109.5
C5—B2—C8	110.2 (2)	H14B—C14—H14C	109.5
N5—C5—B2	177.8 (3)	N10—C15—C16	108.8 (2)
N6—C6—B2	178.7 (3)	N10—C15—C14	110.3 (2)
N7—C7—B2	177.6 (4)	C16—C15—C14	111.6 (2)
N8—C8—B2	179.8 (3)	N10—C15—H15A	108.7
C10—C9—H9A	109.5	C16—C15—H15A	108.7
C10—C9—H9B	109.5	C14—C15—H15A	108.7
H9A—C9—H9B	109.5	C15—N10—H10B	109.5
C10—C9—H9C	109.5	C15—N10—H10C	109.5
H9A—C9—H9C	109.5	H10B—N10—H10C	109.5
H9B—C9—H9C	109.5	C15—N10—H10D	109.5
N9—C10—C9	112.0 (2)	H10B—N10—H10D	109.5
N9—C10—C11	108.2 (2)	H10C—N10—H10D	109.5
C9—C10—C11	110.3 (2)	O3—C16—O4	126.0 (2)
N9—C10—H10A	108.8	O3—C16—C15	124.2 (2)
C9—C10—H10A	108.8	O4—C16—C15	109.8 (2)
C11—C10—H10A	108.8	C16—O4—C17	119.4 (2)
C10—N9—H9D	109.5	O4—C17—C18	107.6 (3)
C10—N9—H9E	109.5	O4—C17—H17A	110.2
H9D—N9—H9E	109.5	C18—C17—H17A	110.2
C10—N9—H9F	109.5	O4—C17—H17B	110.2
H9D—N9—H9F	109.5	C18—C17—H17B	110.2
H9E—N9—H9F	109.5	H17A—C17—H17B	108.5
O1—C11—O2	125.8 (2)	C17—C18—H18A	109.5
O1—C11—C10	124.3 (2)	C17—C18—H18B	109.5
O2—C11—C10	109.8 (2)	H18A—C18—H18B	109.5
C11—O2—C12	117.2 (2)	C17—C18—H18C	109.5
O2—C12—C13	109.4 (3)	H18A—C18—H18C	109.5
O2—C12—H12A	109.8	H18B—C18—H18C	109.5
N9—C10—C11—O1	−7.2 (3)	N10—C15—C16—O3	−6.3 (3)
C9—C10—C11—O1	115.7 (3)	C14—C15—C16—O3	115.6 (3)
N9—C10—C11—O2	175.3 (2)	N10—C15—C16—O4	175.1 (2)
C9—C10—C11—O2	−61.9 (3)	C14—C15—C16—O4	−63.0 (3)
O1—C11—O2—C12	−9.5 (4)	O3—C16—O4—C17	2.5 (4)
C10—C11—O2—C12	168.1 (2)	C15—C16—O4—C17	−178.9 (3)
C11—O2—C12—C13	−86.1 (3)	C16—O4—C17—C18	136.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N9—H9F···N6^i	0.91	2.16	2.920 (3)	141
N10—H10B···N4^ii	0.91	2.05	2.953 (3)	174
N10—H10D···N1	0.91	2.07	2.961 (3)	166
N9—H9E···N8^iii	0.91	2.14	3.001 (3)	158
N10—H10C···N2^iv	0.91	2.15	3.015 (3)	159
N9—H9D···N5^v	0.91	2.14	3.017 (3)	161
N9—H9F···N3^vi	0.91	2.64	3.147 (3)	116

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