Potassium trifluoro­[(Z)-3-methoxy­prop-1-en­yl]borate

In the title salt, K⁺·C₄H₇BF₃O⁻, the K atom is surrounded by six anions making close contacts through seven F [K...F = 2.779 (1)–3.048 (1) Å] and two O [K...O = 2.953 (2) and 3.127 (2) Å] atoms in a trivacant fac-vIC-9 icosa­hedral coordination geometry.

Key indicators

• Single-crystal X-ray study
• T = 291 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.027
• wR factor = 0.072
• Data-to-parameter ratio = 14.4

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   291.000
            Value of melting point given =     0.000
SHFSU01_ALERT_2_C  Test not performed. _refine_ls_shift/su_max and
            _refine_ls_shift/esd_max not present.
            Absolute value of the parameter shift to su ratio given   0.001
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?

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

   1 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
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Organic compounds of tellurium, such as Z-vinylic tellurides, are important synthetic precursors of organometallic molecules and organic salts and can be useful in the synthesis of new potassium vinyl trifluoroborate salts. Organotrifluoroborates represent an alternative to boronic acids, boronate esters, and organoboranes for use in the Suzuki-Miyaura reaction and other transition-metal-catalyzed cross-coupling reactions (Vieira et al. 2008). Following the ideas of Ruiz-Martínez et al. (2008) the geometry around the K⁺ ion can be described as a trivacant icosahedron, fac-vIC-9, a non spherical shape, as shown in Figure 2. The independent molecules in (I) are connected via C3···F2ⁱ = 3.214 (2) Å, C3—H3B···F2ⁱ = 137° (i = x - 1/2, -y + 3/2, z).

Related literature

For related structures, see: Caracelli et al. (2007); Stefani et al.(2006); For related literature, see: Ruiz-Martínez et al. (2008); Vieira et al. (2008).

S2. Experimental

nBuLi (0.8 mmol) was added dropwise at 203 K to a solution of the appropriated Z-vinylic telluride (1 mmol) in Et₂O (6 ml). The bath temperature was raised to 253 K. After 20 minutes B(OiPr)₃ (1.0 mmol) was added at 233 K. After 1 h, a aqueous solution of KHF₂ (4 mmol in 10 ml of water) was added to the reaction mixture. Then, the solvent and water were eliminated by evaporation. To the obtained solid hot acetone was added and the bulk reactional was filtered and dried, yielding 67% of (Z)-potassium vinyltrifluoroborate salt. Single crystals were obtained by slow evaporation from Et₂O.

S3. Refinement

The H atoms were refined in the riding-model approximation, with C—H = 0.93–0.97Å and U_iso(H) = 1.5U_eq(methyl C) or 1.2U_eq(remaining C).

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: PHICHI (Duisenberg et al., 2000); data reduction: EVAL14 (CCD) (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of the title compound showing atom labelling scheme and displacement ellipsoids at the 50% probability level (arbitrary spheres for the H atoms).
	Fig. 2. The trivacant icosahedron, fac-vIC-9, around the K^+ ion. Symmetry operations: i = 1 - x, y - 1/2, 1/2 - z; ii = 1 - x, y - 1, -z; iii = 1 - x, y + 1/2, 1/2 - z; iv = 1 - x, -2 - y, -z; v = x, -3/2 - y, z - 1/2; vi = x, -3/2 - y, 1/2 + z.

Potassium trifluoro[(Z)-3-methoxyprop-1-enyl]borate

Crystal data

K^+·C4H7BF3O^−	F(000) = 360
Mr = 178.01	Dx = 1.653 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9536 reflections
a = 10.882 (2) Å	θ = 2.3–21.8°
b = 7.2668 (15) Å	µ = 0.72 mm^−1
c = 9.2317 (18) Å	T = 291 K
β = 101.52 (3)°	Block, colourless
V = 715.3 (3) Å^3	0.31 × 0.22 × 0.11 mm
Z = 4

Data collection

Enraf–Nonius KappaCCD diffractometer	1327 independent reflections
Radiation source: fine-focus sealed tube	1182 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.059
ϕ and ω scans	θmax = 25.5°, θmin = 4.3°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −13→13
Tmin = 0.804, Tmax = 0.924	k = −8→8
16605 measured reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.072	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0364P)^2 + 0.2723P] where P = (Fo^2 + 2Fc^2)/3
1327 reflections	(Δ/σ)max < 0.001
92 parameters	Δρmax = 0.25 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3

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
B	0.64509 (18)	−0.7960 (2)	0.0837 (2)	0.0305 (4)
C1	0.77652 (16)	−0.7044 (2)	0.16327 (19)	0.0371 (4)
H1	0.8143	−0.7569	0.253	0.045*
C2	0.83849 (15)	−0.5637 (2)	0.11809 (19)	0.0352 (4)
H2	0.9123	−0.5254	0.1798	0.042*
C3	0.79730 (17)	−0.4641 (2)	−0.02438 (18)	0.0379 (4)
H3A	0.863	−0.4722	−0.0814	0.045*
H3B	0.7233	−0.5242	−0.0806	0.045*
C4	0.8776 (2)	−0.1624 (3)	0.0361 (3)	0.0588 (6)
H4A	0.8539	−0.0349	0.0304	0.088*
H4B	0.9337	−0.1857	−0.0299	0.088*
H4C	0.9186	−0.1916	0.1354	0.088*
F1	0.63816 (10)	−0.84405 (14)	−0.06632 (11)	0.0438 (3)
F2	0.61847 (9)	−0.95573 (12)	0.16043 (10)	0.0396 (3)
F3	0.54238 (9)	−0.67152 (13)	0.08481 (11)	0.0384 (3)
K	0.40701 (3)	−0.83116 (5)	0.27917 (4)	0.03619 (15)
O	0.76899 (12)	−0.27319 (17)	−0.00483 (16)	0.0469 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
B	0.0374 (9)	0.0264 (9)	0.0288 (9)	−0.0009 (7)	0.0095 (7)	0.0035 (7)
C1	0.0362 (9)	0.0389 (9)	0.0344 (8)	−0.0009 (7)	0.0030 (7)	0.0085 (7)
C2	0.0304 (8)	0.0362 (9)	0.0376 (9)	−0.0027 (7)	0.0034 (7)	0.0001 (7)
C3	0.0488 (10)	0.0295 (9)	0.0353 (9)	−0.0089 (7)	0.0080 (7)	−0.0018 (7)
C4	0.0504 (12)	0.0335 (10)	0.0867 (17)	−0.0095 (9)	−0.0005 (11)	−0.0073 (10)
F1	0.0508 (6)	0.0504 (6)	0.0312 (5)	−0.0058 (5)	0.0104 (4)	−0.0054 (4)
F2	0.0477 (6)	0.0291 (5)	0.0412 (6)	−0.0057 (4)	0.0064 (4)	0.0077 (4)
F3	0.0359 (5)	0.0332 (5)	0.0454 (6)	0.0032 (4)	0.0059 (4)	0.0007 (4)
K	0.0380 (2)	0.0316 (2)	0.0396 (2)	0.00022 (14)	0.00919 (16)	0.00628 (15)
O	0.0390 (7)	0.0293 (6)	0.0682 (9)	−0.0014 (5)	0.0007 (6)	0.0024 (6)

Geometric parameters (Å, º)

B—F1	1.415 (2)	C2—H2	0.9300
B—F2	1.4198 (19)	C3—O	1.440 (2)
B—F3	1.440 (2)	C3—H3A	0.9700
B—C1	1.615 (3)	C3—H3B	0.9700
B—K	3.450 (2)	C4—O	1.417 (2)
C1—C2	1.337 (2)	C4—H4A	0.9600
C1—H1	0.9300	C4—H4B	0.9600
C2—C3	1.490 (2)	C4—H4C	0.9600
F1—B—F2	108.08 (13)	O—C3—H3A	109.0
F1—B—F3	105.82 (13)	C2—C3—H3A	109.0
F2—B—F3	105.89 (13)	O—C3—H3B	109.0
F1—B—C1	114.59 (15)	C2—C3—H3B	109.0
F2—B—C1	111.11 (13)	H3A—C3—H3B	107.8
F3—B—C1	110.86 (13)	O—C4—H4A	109.5
C2—C1—B	129.00 (15)	O—C4—H4B	109.5
C2—C1—H1	115.5	H4A—C4—H4B	109.5
B—C1—H1	115.5	O—C4—H4C	109.5
C1—C2—C3	124.44 (15)	H4A—C4—H4C	109.5
C1—C2—H2	117.8	H4B—C4—H4C	109.5
C3—C2—H2	117.8	C4—O—C3	113.13 (14)
O—C3—C2	113.05 (14)
F1—B—C1—C2	50.8 (3)	B—C1—C2—C3	−2.2 (3)
F2—B—C1—C2	173.64 (17)	C1—C2—C3—O	116.83 (19)
F3—B—C1—C2	−68.9 (2)	C2—C3—O—C4	76.3 (2)