3-tert-Butyl-1-(2-pyridyl­methyl)-3H-imidazolium bromide hydrate

The structure of the title compound, C₁₃H₁₈N₃⁺·Br^-·H₂O, shows that the cation and the bromide anion are linked via the water mol­ecule through weak intermolecular hydrogen bonds. The water was not detected by NMR spectroscopy, but the cell content is in agreement with the elemental analysis. The presence of water plays an important role in further reactions.

S1. Comment

It has been reported that mixed-donor carbene complexes of late transition metals, such as Pd, Ru and Rh, are highly active precatalysts for Heck coupling and other important reactions (Tulloch et al., 2000). The title compound, (I), was synthesized in order to prepare N-heterocyclic carbene complexes, to act as novel catalysts. Because of a disagreement within the analytical data, obtained from elemental analysis and NMR spectroscopy, the pure compound was recrystallized from acetone. The cell content, obtained from the stucture determination, agrees with the results of the elemental analysis, in that one molecule of water is associated with each ion pair. Intermolecular hydrogen bonding is observed between proton H321 from one methyl group of the tert-butyl group and the O atom of the water molecule. A proton from each of the other two methyl groups (H112 and H123) also points towards O1. There are also intermolecular hydrogen bonds to a pair of symmetry-equivalent bromide anions from the H atoms of the water molecule (Table 1).

S2. Experimental

The title compound was prepared by the quarternization of 1-tert-butyl-imidazole with picolyl bromide in methanol. The crude product was recrystallized by cooling a saturated solution of (I) in dried acetone to 238 K. Compound (I) was characterized by ¹H NMR, mass spectroscopy and elemental analysis: ¹H NMR (300 MHz, DMSO-d₆) δ 1.6 (9H, s, ^tBu), 5.6 (2H, s, CH₂), 7.6 and 8.6 (2 × 1H, d, 4,5-imidazolium-CH), 7.5, 7.9, 8.0 and 8.1 (4 × 1H, m, 3,4,5,6-picolyl-CH), 9.5 (H, s, 2-imidazolium-CH). LRMS (ESIPOS) m/z 216 M⁺. Analysis found: C 49.68, H 6.43, N 13.38%; C₁₃H₂₀BrN₃O requires: C 49.69, H 6.42, N 13.37%.

S3. Refinement

All H atoms were located by difference Fourier sythesis and refined isotropically [C—H = 0.89 (2)–1.05 (4) Å]. No constraints or restraints were applied to the structural models.

Computing details

Data collection: COLLECT (Hooft, 1998); cell refinement: SCALEPACK (Otwinowski & Minor 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: PLATON (Spek, 1990).

3-tert-Butyl-1-pyridin-2-ylmethyl-3H-imidazolium bromide-water (1/1)

Crystal data

C13H18N3^+·Br^−·H2O	Dx = 1.407 Mg m^−3
Mr = 314.23	Melting point: 338 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.7083 (19) Å	Cell parameters from 12783 reflections
b = 13.214 (3) Å	θ = 1.0–26.4°
c = 11.574 (2) Å	µ = 2.76 mm^−1
β = 92.11 (3)°	T = 150 K
V = 1483.8 (5) Å^3	Prism, colorless
Z = 4	0.20 × 0.20 × 0.13 mm
F(000) = 648

Data collection

Enraf-Nonius KappaCCD area-detector diffractometer	3021 independent reflections
Radiation source: Nonius FR591 rotating anode	2608 reflections with I > 2σ(I)
Detector resolution: 9.091 pixels mm^-1 pixels mm^-1	Rint = 0.048
ϕ and ω scans to fill Ewald sphere	θmax = 26.4°, θmin = 2.1°
Absorption correction: multi-scan SORTAV (Blessing, 1995)	h = −12→12
Tmin = 0.608, Tmax = 0.724	k = −16→16
30583 measured reflections	l = −14→14

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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.071	All H-atom parameters refined
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0362P)^2 + 0.7258P] where P = (Fo^2 + 2Fc^2)/3
3021 reflections	(Δ/σ)max < 0.001
243 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.64 e Å^−3

Special details

Experimental. The crystall was mounted on a glass fibre with silicon grease. The crystal-to-detector distance was 40 mm. No decay correction was applied to the obtaind data.

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
Br1	0.18513 (2)	0.450742 (16)	0.167066 (18)	0.03382 (9)
O1	0.1243 (2)	0.60311 (16)	−0.05503 (19)	0.0586 (5)
H1O	0.133 (4)	0.554 (3)	0.008 (4)	0.096 (13)*
H2O	0.036 (4)	0.586 (3)	−0.093 (3)	0.098 (12)*
N3	0.50407 (16)	0.70403 (12)	0.21611 (14)	0.0257 (4)
C9	0.6239 (2)	0.75062 (16)	0.20567 (18)	0.0295 (4)
N1	0.72228 (18)	0.85982 (14)	−0.00486 (16)	0.0354 (4)
N2	0.70269 (17)	0.69535 (13)	0.13871 (14)	0.0280 (4)
C8	0.5068 (2)	0.61527 (16)	0.15283 (17)	0.0300 (5)
C7	0.6306 (2)	0.61038 (16)	0.10490 (18)	0.0322 (5)
C5	0.8379 (2)	0.80788 (15)	0.01385 (17)	0.0281 (4)
C6	0.8410 (2)	0.72510 (19)	0.1046 (2)	0.0337 (5)
C2	0.8407 (3)	0.96158 (17)	−0.1413 (2)	0.0394 (5)
C3	0.9593 (3)	0.90656 (19)	−0.1212 (2)	0.0428 (6)
C4	0.9586 (2)	0.82838 (18)	−0.0428 (2)	0.0385 (5)
C1	0.7261 (3)	0.93589 (18)	−0.0822 (2)	0.0402 (5)
C10	0.3859 (2)	0.74071 (15)	0.28505 (17)	0.0292 (4)
C11	0.2587 (2)	0.74743 (19)	0.2046 (2)	0.0357 (5)
C12	0.3641 (3)	0.6647 (2)	0.3811 (2)	0.0432 (6)
C13	0.4228 (3)	0.8456 (2)	0.3321 (3)	0.0528 (7)
H61	0.887 (3)	0.6669 (19)	0.073 (2)	0.044 (7)*
H81	0.431 (3)	0.5736 (17)	0.146 (2)	0.034 (6)*
H62	0.889 (2)	0.7519 (17)	0.173 (2)	0.038 (6)*
H31	1.040 (3)	0.922 (2)	−0.163 (3)	0.059 (8)*
H71	0.668 (3)	0.5585 (18)	0.057 (2)	0.043 (7)*
H11	0.640 (3)	0.9733 (18)	−0.089 (2)	0.042 (7)*
H9	0.652 (2)	0.8064 (17)	0.2420 (18)	0.025 (5)*
H121	0.343 (3)	0.599 (2)	0.354 (2)	0.045 (7)*
H131	0.504 (3)	0.8375 (18)	0.388 (2)	0.045 (7)*
H122	0.444 (3)	0.663 (2)	0.432 (2)	0.058 (8)*
H111	0.227 (3)	0.679 (2)	0.172 (2)	0.040 (6)*
H112	0.187 (3)	0.7733 (19)	0.248 (2)	0.045 (7)*
H132	0.345 (3)	0.866 (2)	0.378 (3)	0.064 (8)*
H21	0.841 (3)	1.014 (2)	−0.198 (2)	0.053 (7)*
H123	0.290 (3)	0.684 (2)	0.426 (2)	0.055 (8)*
H41	1.037 (3)	0.7895 (19)	−0.026 (2)	0.044 (7)*
H113	0.275 (3)	0.793 (2)	0.141 (2)	0.048 (7)*
H133	0.442 (4)	0.897 (3)	0.266 (3)	0.091 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.03197 (15)	0.03281 (14)	0.03663 (14)	0.00503 (8)	0.00065 (9)	−0.00401 (8)
O1	0.0383 (11)	0.0695 (13)	0.0678 (13)	−0.0124 (9)	−0.0008 (9)	0.0240 (11)
N3	0.0250 (9)	0.0288 (9)	0.0238 (8)	−0.0019 (7)	0.0071 (7)	−0.0019 (7)
C9	0.0295 (12)	0.0282 (11)	0.0312 (10)	−0.0027 (9)	0.0070 (9)	−0.0027 (9)
N1	0.0291 (10)	0.0397 (10)	0.0376 (10)	0.0004 (8)	0.0054 (8)	0.0073 (8)
N2	0.0268 (9)	0.0314 (9)	0.0263 (8)	−0.0001 (7)	0.0082 (7)	0.0035 (7)
C8	0.0315 (12)	0.0291 (11)	0.0299 (10)	−0.0047 (9)	0.0059 (9)	−0.0062 (8)
C7	0.0337 (12)	0.0324 (11)	0.0311 (10)	0.0007 (9)	0.0077 (9)	−0.0038 (9)
C5	0.0277 (11)	0.0306 (10)	0.0262 (10)	−0.0032 (8)	0.0044 (8)	−0.0020 (8)
C6	0.0225 (11)	0.0434 (13)	0.0357 (12)	0.0010 (9)	0.0086 (9)	0.0069 (10)
C2	0.0494 (15)	0.0321 (12)	0.0369 (12)	−0.0082 (10)	0.0067 (11)	0.0050 (10)
C3	0.0404 (14)	0.0410 (13)	0.0480 (14)	−0.0096 (11)	0.0163 (11)	0.0051 (11)
C4	0.0288 (12)	0.0419 (13)	0.0456 (13)	−0.0001 (10)	0.0122 (10)	0.0066 (10)
C1	0.0365 (14)	0.0405 (13)	0.0438 (13)	0.0016 (10)	0.0029 (11)	0.0082 (10)
C10	0.0236 (11)	0.0360 (11)	0.0285 (10)	−0.0006 (8)	0.0066 (8)	−0.0086 (9)
C11	0.0326 (13)	0.0392 (13)	0.0353 (12)	0.0052 (10)	0.0028 (10)	−0.0020 (10)
C12	0.0294 (13)	0.072 (2)	0.0287 (11)	0.0062 (12)	0.0099 (11)	0.0051 (12)
C13	0.0350 (14)	0.0547 (17)	0.0696 (18)	−0.0056 (12)	0.0145 (14)	−0.0373 (15)

Geometric parameters (Å, º)

O1—H1O	0.98 (4)	C2—C3	1.374 (4)
O1—H2O	0.98 (4)	C2—H21	0.96 (3)
N3—C9	1.326 (3)	C3—C4	1.376 (3)
N3—C8	1.383 (3)	C3—H31	0.96 (3)
N3—C10	1.502 (2)	C4—H41	0.93 (3)
C9—N2	1.327 (3)	C1—H11	0.97 (3)
C9—H9	0.89 (2)	C10—C12	1.519 (3)
N1—C5	1.327 (3)	C10—C11	1.521 (3)
N1—C1	1.348 (3)	C10—C13	1.527 (3)
N2—C7	1.373 (3)	C11—H111	1.03 (3)
N2—C6	1.467 (3)	C11—H112	0.94 (3)
C8—C7	1.344 (3)	C11—H113	0.97 (3)
C8—H81	0.92 (2)	C12—H121	0.95 (3)
C7—H71	0.96 (3)	C12—H122	0.96 (3)
C5—C4	1.390 (3)	C12—H123	0.94 (3)
C5—C6	1.516 (3)	C13—H131	1.00 (3)
C6—H61	0.97 (3)	C13—H132	0.97 (3)
C6—H62	0.97 (2)	C13—H133	1.05 (4)
C2—C1	1.370 (4)
H1O—O1—H2O	104 (3)	C4—C3—H31	121.0 (17)
C9—N3—C8	108.15 (17)	C3—C4—C5	118.8 (2)
C9—N3—C10	126.07 (17)	C3—C4—H41	122.0 (16)
C8—N3—C10	125.78 (16)	C5—C4—H41	119.2 (16)
N3—C9—N2	108.90 (19)	N1—C1—C2	124.0 (2)
N3—C9—H9	126.9 (14)	N1—C1—H11	113.1 (15)
N2—C9—H9	123.9 (14)	C2—C1—H11	122.8 (15)
C5—N1—C1	116.77 (19)	N3—C10—C12	107.76 (17)
C9—N2—C7	108.54 (18)	N3—C10—C11	108.21 (17)
C9—N2—C6	124.20 (19)	C12—C10—C11	110.79 (19)
C7—N2—C6	127.21 (18)	N3—C10—C13	107.99 (18)
C7—C8—N3	107.10 (19)	C12—C10—C13	112.1 (2)
C7—C8—H81	131.4 (15)	C11—C10—C13	109.9 (2)
N3—C8—H81	121.4 (15)	C10—C11—H111	113.5 (14)
C8—C7—N2	107.31 (19)	C10—C11—H112	106.9 (15)
C8—C7—H71	129.2 (15)	H111—C11—H112	108 (2)
N2—C7—H71	123.5 (15)	C10—C11—H113	110.3 (15)
N1—C5—C4	123.0 (2)	H111—C11—H113	109 (2)
N1—C5—C6	118.77 (18)	H112—C11—H113	109 (2)
C4—C5—C6	118.15 (19)	C10—C12—H121	113.8 (16)
N2—C6—C5	112.65 (18)	C10—C12—H122	109.4 (17)
N2—C6—H61	109.4 (15)	H121—C12—H122	110 (2)
C5—C6—H61	107.7 (15)	C10—C12—H123	110.9 (17)
N2—C6—H62	107.2 (14)	H121—C12—H123	106 (2)
C5—C6—H62	107.3 (14)	H122—C12—H123	106 (2)
H61—C6—H62	113 (2)	C10—C13—H131	107.5 (15)
C1—C2—C3	118.4 (2)	C10—C13—H132	105.5 (17)
C1—C2—H21	123.2 (17)	H131—C13—H132	107 (2)
C3—C2—H21	118.4 (17)	C10—C13—H133	112 (2)
C2—C3—C4	119.0 (2)	H131—C13—H133	112 (2)
C2—C3—H31	120.0 (17)	H132—C13—H133	112 (3)
C8—N3—C9—N2	−0.1 (2)	C4—C5—C6—N2	−167.1 (2)
C10—N3—C9—N2	179.64 (17)	C1—C2—C3—C4	−0.2 (4)
N3—C9—N2—C7	0.1 (2)	C2—C3—C4—C5	−0.2 (4)
N3—C9—N2—C6	177.71 (18)	N1—C5—C4—C3	0.6 (4)
C9—N3—C8—C7	0.0 (2)	C6—C5—C4—C3	−176.9 (2)
C10—N3—C8—C7	−179.70 (18)	C5—N1—C1—C2	0.1 (4)
N3—C8—C7—N2	0.0 (2)	C3—C2—C1—N1	0.2 (4)
C9—N2—C7—C8	−0.1 (2)	C9—N3—C10—C12	−116.2 (2)
C6—N2—C7—C8	−177.60 (19)	C8—N3—C10—C12	63.4 (3)
C1—N1—C5—C4	−0.5 (3)	C9—N3—C10—C11	123.9 (2)
C1—N1—C5—C6	176.9 (2)	C8—N3—C10—C11	−56.4 (3)
C9—N2—C6—C5	−74.3 (3)	C9—N3—C10—C13	5.0 (3)
C7—N2—C6—C5	102.8 (2)	C8—N3—C10—C13	−175.3 (2)
N1—C5—C6—N2	15.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C13—H132···O1^i	0.97 (3)	2.34 (3)	3.292 (3)	165 (2)
O1—H2O···Br1^ii	0.98 (4)	2.33 (4)	3.305 (2)	175 (3)
O1—H1O···Br1	0.98 (4)	2.33 (4)	3.301 (2)	171 (3)

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