L-Histidinium tetra­fluoro­borate

The title compound, C₆H₁₀N₃O₂⁺·BF₄⁻, crystallizes with one histidinium cation and one tetra­fluoro­borate anion in the asymmetric unit. The protonated cation and the deprotonated anion are linked through a number of inter­molecular N—H...O and N—H...F hydrogen bonds, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.025
• wR factor = 0.067
• Data-to-parameter ratio = 5.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT089_ALERT_3_B Poor Data / Parameter Ratio (Zmax .LT. 18) .....       5.07
PLAT222_ALERT_3_B Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       4.31 Ratio

Alert level C
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         B1
PLAT350_ALERT_3_C Short   C-H Bond (0.96A)   C2     -   H2     ...       0.84 Ang.
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              B F4

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           67.88
           From the CIF: _reflns_number_total                903
           Count of symmetry unique reflns          903
           Completeness (_total/calc)            100.00%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

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

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Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1988); cell refinement: CAD-4 Software; data reduction: XCAD4 in WinGX (Farrugia, 1999); program(s) used to solve structure: SIR92 in WinGX; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-32 in WinGX; software used to prepare material for publication: SHELXL97.

L-Histidinium tetrafluoroborate ?

Crystal data

C6H10N3O2^+·BF4^−	F(000) = 248
Mr = 242.98	Dx = 1.732 Mg m^−3
Monoclinic, P21	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 5.0259 (8) Å	θ = 20–30°
b = 9.089 (2) Å	µ = 1.59 mm^−1
c = 10.218 (2) Å	T = 293 K
β = 93.482 (15)°	Prism, colourless
V = 465.91 (17) Å^3	0.3 × 0.2 × 0.2 mm
Z = 2

Data collection

Enraf-Nonius CAD-4 diffractometer	902 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 67.9°, θmin = 4.3°
ω–2θ scans	h = 0→6
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
Tmin = 0.661, Tmax = 0.727	l = −12→12
1008 measured reflections	2 standard reflections every 60 min
903 independent reflections	intensity decay: none

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)] = 0.025	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.067	w = 1/[σ^2(Fo^2) + (0.0343P)^2 + 0.1648P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max < 0.001
903 reflections	Δρmax = 0.16 e Å^−3
178 parameters	Δρmin = −0.15 e Å^−3
1 restraint	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.088 (4)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.9070 (6)	0.4571 (3)	0.3540 (3)	0.0372 (6)
C2	1.1016 (5)	0.2416 (3)	0.3552 (2)	0.0330 (6)
C3	0.8821 (5)	0.2334 (3)	0.2719 (2)	0.0268 (5)
C4	0.7733 (5)	0.1089 (3)	0.1904 (2)	0.0300 (5)
H4A	0.6138	0.0721	0.2281	0.036*
H4B	0.9032	0.0299	0.1930	0.036*
C5	0.7052 (4)	0.1515 (3)	0.0472 (2)	0.0220 (5)
C6	0.5759 (4)	0.0196 (2)	−0.0249 (2)	0.0238 (5)
N1	1.1117 (5)	0.3823 (3)	0.4042 (2)	0.0378 (6)
N2	0.7618 (4)	0.3695 (3)	0.2748 (2)	0.0309 (5)
N3	0.9469 (4)	0.2021 (2)	−0.0164 (2)	0.0261 (5)
O1	0.7086 (3)	−0.0548 (2)	−0.10060 (17)	0.0327 (4)
O2	0.3388 (3)	−0.0050 (2)	−0.00061 (18)	0.0343 (5)
F1	0.4664 (4)	−0.0904 (2)	0.39713 (17)	0.0487 (5)
F2	0.5355 (4)	−0.2560 (3)	0.2368 (2)	0.0657 (6)
F3	0.1214 (3)	−0.2125 (3)	0.29443 (19)	0.0565 (5)
F4	0.4099 (5)	−0.3312 (2)	0.4355 (2)	0.0639 (6)
B1	0.3837 (6)	−0.2222 (4)	0.3410 (3)	0.0341 (7)
H3C	1.015 (6)	0.286 (4)	0.018 (3)	0.033 (8)*
H3A	1.083 (6)	0.137 (4)	−0.007 (3)	0.034 (8)*
H2'	0.614 (6)	0.398 (5)	0.225 (3)	0.044 (9)*
H3B	0.887 (7)	0.235 (5)	−0.100 (4)	0.058 (10)*
H2	1.219 (6)	0.179 (4)	0.376 (3)	0.042 (9)*
H1	0.887 (8)	0.560 (6)	0.366 (4)	0.069 (12)*
H1'	1.235 (7)	0.408 (5)	0.451 (3)	0.049 (10)*
H5	0.589 (5)	0.228 (3)	0.039 (2)	0.016 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0502 (16)	0.0292 (14)	0.0312 (13)	−0.0013 (12)	−0.0043 (11)	−0.0044 (12)
C2	0.0326 (13)	0.0376 (15)	0.0279 (12)	0.0032 (12)	−0.0053 (9)	0.0008 (11)
C3	0.0311 (12)	0.0261 (13)	0.0230 (10)	−0.0015 (10)	−0.0002 (8)	0.0024 (9)
C4	0.0380 (13)	0.0226 (12)	0.0289 (12)	−0.0035 (11)	−0.0031 (9)	0.0015 (10)
C5	0.0225 (11)	0.0166 (11)	0.0261 (11)	0.0014 (9)	−0.0043 (8)	−0.0007 (9)
C6	0.0255 (11)	0.0170 (11)	0.0278 (11)	0.0014 (9)	−0.0077 (8)	0.0017 (9)
N1	0.0393 (12)	0.0445 (15)	0.0285 (10)	−0.0091 (11)	−0.0064 (9)	−0.0076 (11)
N2	0.0364 (11)	0.0274 (12)	0.0280 (10)	0.0024 (9)	−0.0069 (8)	−0.0004 (9)
N3	0.0273 (11)	0.0193 (9)	0.0313 (11)	−0.0027 (9)	−0.0007 (8)	−0.0014 (9)
O1	0.0343 (9)	0.0251 (9)	0.0388 (9)	−0.0012 (7)	0.0033 (7)	−0.0093 (8)
O2	0.0245 (9)	0.0263 (9)	0.0516 (11)	−0.0026 (7)	−0.0016 (7)	−0.0049 (8)
F1	0.0666 (11)	0.0326 (9)	0.0452 (9)	−0.0092 (9)	−0.0114 (8)	−0.0040 (8)
F2	0.0608 (11)	0.0783 (16)	0.0578 (11)	−0.0004 (11)	0.0031 (8)	−0.0233 (12)
F3	0.0426 (9)	0.0632 (13)	0.0611 (11)	0.0021 (9)	−0.0181 (8)	−0.0001 (11)
F4	0.0856 (14)	0.0417 (11)	0.0605 (12)	−0.0097 (10)	−0.0262 (10)	0.0185 (10)
B1	0.0364 (15)	0.0302 (16)	0.0341 (15)	−0.0031 (13)	−0.0098 (11)	−0.0016 (13)

Geometric parameters (Å, º)

C1—N1	1.311 (4)	C5—H5	0.91 (3)
C1—N2	1.322 (4)	C6—O1	1.251 (3)
C1—H1	0.95 (5)	C6—O2	1.252 (3)
C2—C3	1.354 (4)	N1—H1'	0.79 (4)
C2—N1	1.373 (4)	N2—H2'	0.91 (3)
C2—H2	0.83 (4)	N3—H3C	0.90 (4)
C3—N2	1.378 (3)	N3—H3A	0.90 (4)
C3—C4	1.489 (3)	N3—H3B	0.93 (4)
C4—C5	1.532 (3)	F1—B1	1.381 (4)
C4—H4A	0.9700	F2—B1	1.382 (4)
C4—H4B	0.9700	F3—B1	1.377 (3)
C5—N3	1.485 (3)	F4—B1	1.384 (4)
C5—C6	1.531 (3)
N1—C1—N2	108.5 (3)	O1—C6—O2	125.2 (2)
N1—C1—H1	123 (3)	O1—C6—C5	119.6 (2)
N2—C1—H1	128 (3)	O2—C6—C5	115.2 (2)
C3—C2—N1	106.9 (3)	C1—N1—C2	109.3 (2)
C3—C2—H2	131 (3)	C1—N1—H1'	131 (3)
N1—C2—H2	122 (3)	C2—N1—H1'	120 (3)
C2—C3—N2	106.2 (2)	C1—N2—C3	109.1 (2)
C2—C3—C4	130.6 (2)	C1—N2—H2'	125 (3)
N2—C3—C4	123.2 (2)	C3—N2—H2'	126 (3)
C3—C4—C5	113.3 (2)	C5—N3—H3C	113 (2)
C3—C4—H4A	108.9	C5—N3—H3A	113 (2)
C5—C4—H4A	108.9	H3C—N3—H3A	104 (3)
C3—C4—H4B	108.9	C5—N3—H3B	106 (2)
C5—C4—H4B	108.9	H3C—N3—H3B	100 (3)
H4A—C4—H4B	107.7	H3A—N3—H3B	120 (3)
N3—C5—C6	111.52 (18)	F3—B1—F1	110.2 (3)
N3—C5—C4	110.79 (19)	F3—B1—F2	108.0 (2)
C6—C5—C4	108.99 (19)	F1—B1—F2	110.3 (3)
N3—C5—H5	105.0 (16)	F3—B1—F4	109.6 (3)
C6—C5—H5	108.0 (16)	F1—B1—F4	108.5 (2)
C4—C5—H5	112.5 (15)	F2—B1—F4	110.2 (3)
N1—C2—C3—N2	−1.2 (3)	N3—C5—C6—O2	−161.8 (2)
N1—C2—C3—C4	179.4 (2)	C4—C5—C6—O2	75.6 (3)
C2—C3—C4—C5	−130.8 (3)	N2—C1—N1—C2	0.7 (3)
N2—C3—C4—C5	49.9 (3)	C3—C2—N1—C1	0.3 (3)
C3—C4—C5—N3	61.3 (3)	N1—C1—N2—C3	−1.4 (3)
C3—C4—C5—C6	−175.68 (19)	C2—C3—N2—C1	1.6 (3)
N3—C5—C6—O1	18.8 (3)	C4—C3—N2—C1	−178.9 (2)
C4—C5—C6—O1	−103.9 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3C···O1^i	0.90 (4)	2.14 (4)	3.010 (3)	161 (3)
N3—H3A···O2^ii	0.90 (4)	1.82 (4)	2.722 (3)	174 (3)
N2—H2′···O1^iii	0.91 (3)	2.04 (3)	2.953 (3)	174 (3)
N3—H3B···F3^iii	0.93 (4)	2.05 (4)	2.945 (3)	161 (3)
N1—H1′···F1^iv	0.79 (4)	2.09 (4)	2.856 (3)	161 (4)

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