Octane-1,8-diyldipyridinium dibromide dihydrate

The asymmetric unit of the title compound, C₁₈H₂₆N₂²⁺·2Br⁻·2H₂O, consists of one-half of the organic cation, one Br⁻ anion and one water mol­ecule. The organic cation is situated on a centre of inversion. The dihedral angle between the pyridine ring and the plane of the central linkage is 59.3 (1)°. The cations, anions and water mol­ecules are linked via O—H...Br, C—H...Br and C—H...O hydrogen bonds, forming a three-dimensional framework.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.029
• wR factor = 0.077
• Data-to-parameter ratio = 23.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.92
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          2

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.915
            Tmax scaled      0.490 Tmin scaled      0.347

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

As part of our ongoing investigation on bipyridyl compounds, we present here the crystal structure of the title compound, (I), which can develop strong intermolecular interactions with cucurbit[n]urils (CB[n]) (Freeman et al., 1981; Day et al., 2000, 2002; Kim et al., 2000).

The asymmetric unit of compound (I) (Fig. 1) consists of one-half of the organic cation, one Br^- anion and one lattice water molecule. The organic cation is situated on a centre of inversion which coincides with the midpoint of the C9—C9ⁱ bond [symmetry code: (i) 1 - x, 1 - y, -z]. The two pyridine rings are parallel by virtue of the centre of symmetry. The dihedral angle between the pyridine ring and the central C6—C9/C6ⁱ—C9ⁱ chain is 59.3 (1)°. The cations, anions and water molecules are linked via O—H···Br, C—H···Br and C—H···O hydrogen bonds (Table 1) forming a three-dimensional framework.

Related literature

For general background, see: Day et al. (2000, 2002); Freeman et al. (1981); Kim et al. (2000).

S2. Experimental

A solution of 1,8-dibromine-octane (2.72 g, 0.01 mol) was added to a stirred solution of pyridine (1.98 g, 0.025 mol) in 1,4-dioxane (50 ml) at 383 K for 5 h. After cooling to room temperature, the mixture was filtered. The solid product was dissolved in 80 ml water, and then set aside for four weeks to obtain colourless crystals of the title compound.

S3. Refinement

Water H atoms were located in a difference Fourier map and refined as riding in their as-found positions relative to the parent O atom, with U_iso(H) = 1.2U_eq(O). All other H atoms were placed in calculated positions and refined as riding, with C—H = 0.93–0.97 Å and U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); 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 (I), showing the atom-labelling scheme for the asymmetric unit. Displacement ellipsoids are drawn at the 50% probability level. unlabelled atoms are related to labelled atoms by the symmetry operation (1 - x, 1 - y, -z). Symmetry related bromide ion and water molecule are not shown.

Octane-1,8-diyldipyridinium dibromide dihydrate

Crystal data

C18H26N2^2+·2(Br^−)·2H2O	F(000) = 952
Mr = 466.26	Dx = 1.429 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 21410 reflections
a = 9.8329 (7) Å	θ = 2.5–27.6°
b = 13.3000 (11) Å	µ = 3.75 mm^−1
c = 16.5688 (13) Å	T = 273 K
V = 2166.8 (3) Å^3	Prism, colourless
Z = 4	0.32 × 0.24 × 0.19 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	2503 independent reflections
Radiation source: fine-focus sealed tube	1842 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
φ and ω scans	θmax = 27.6°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −12→12
Tmin = 0.380, Tmax = 0.536	k = −17→17
21410 measured reflections	l = −15→21

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) = 0.077	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0352P)^2 + 0.8723P] where P = (Fo^2 + 2Fc^2)/3
2503 reflections	(Δ/σ)max = 0.001
109 parameters	Δρmax = 0.25 e Å^−3
0 restraints	Δρmin = −0.39 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
Br1	0.28891 (2)	0.652327 (19)	0.328729 (15)	0.05280 (11)
N1	0.44180 (18)	0.35645 (13)	0.32104 (10)	0.0376 (4)
C1	0.3916 (3)	0.40288 (17)	0.38614 (14)	0.0507 (6)
H1	0.3246	0.4517	0.3801	0.061*
C2	0.4380 (3)	0.3791 (2)	0.46131 (16)	0.0642 (8)
H2	0.4014	0.4105	0.5065	0.077*
C3	0.5389 (3)	0.3088 (2)	0.46995 (16)	0.0660 (8)
H3	0.5725	0.2931	0.5209	0.079*
C4	0.5895 (3)	0.2622 (2)	0.40288 (15)	0.0588 (7)
H4	0.6582	0.2146	0.4077	0.071*
C5	0.5382 (2)	0.28617 (18)	0.32886 (13)	0.0475 (6)
H5	0.5707	0.2532	0.2832	0.057*
C6	0.3864 (2)	0.37965 (18)	0.23978 (13)	0.0455 (5)
H6A	0.3137	0.4285	0.2453	0.055*
H6B	0.3476	0.3189	0.2170	0.055*
C7	0.4916 (2)	0.42052 (18)	0.18213 (12)	0.0432 (5)
H7A	0.5633	0.3712	0.1749	0.052*
H7B	0.5320	0.4808	0.2048	0.052*
C8	0.4286 (2)	0.44515 (19)	0.10078 (13)	0.0444 (5)
H8A	0.3865	0.3850	0.0791	0.053*
H8B	0.3577	0.4950	0.1084	0.053*
C9	0.5310 (2)	0.48488 (17)	0.04014 (12)	0.0408 (5)
H9A	0.5766	0.5428	0.0633	0.049*
H9B	0.5992	0.4335	0.0306	0.049*
O1W	0.1270 (2)	0.6061 (2)	0.15455 (12)	0.0973 (8)
H1WA	0.0442	0.6131	0.1647	0.117*
H1WB	0.1689	0.6117	0.1965	0.117*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.04958 (16)	0.05876 (17)	0.05006 (17)	0.00012 (12)	−0.00083 (11)	0.01642 (11)
N1	0.0424 (10)	0.0428 (10)	0.0277 (9)	−0.0036 (8)	0.0058 (7)	0.0044 (7)
C1	0.0627 (14)	0.0464 (13)	0.0429 (14)	0.0058 (12)	0.0161 (12)	0.0025 (11)
C2	0.094 (2)	0.0637 (16)	0.0345 (14)	−0.0017 (16)	0.0104 (14)	−0.0069 (12)
C3	0.081 (2)	0.0830 (19)	0.0341 (14)	−0.0090 (17)	−0.0084 (14)	0.0108 (14)
C4	0.0601 (15)	0.0672 (17)	0.0492 (15)	0.0092 (13)	−0.0038 (13)	0.0141 (13)
C5	0.0528 (14)	0.0527 (14)	0.0368 (13)	0.0072 (11)	0.0061 (11)	0.0008 (11)
C6	0.0437 (12)	0.0601 (13)	0.0326 (12)	−0.0035 (11)	−0.0004 (10)	0.0098 (11)
C7	0.0447 (12)	0.0539 (13)	0.0311 (12)	−0.0047 (11)	0.0010 (10)	0.0064 (10)
C8	0.0437 (12)	0.0590 (14)	0.0305 (11)	−0.0035 (10)	−0.0010 (10)	0.0069 (10)
C9	0.0402 (11)	0.0540 (13)	0.0281 (11)	−0.0067 (10)	−0.0031 (9)	0.0036 (10)
O1W	0.0625 (12)	0.177 (3)	0.0519 (12)	0.0086 (16)	−0.0006 (10)	−0.0161 (14)

Geometric parameters (Å, º)

N1—C1	1.337 (3)	C6—H6A	0.97
N1—C5	1.337 (3)	C6—H6B	0.97
N1—C6	1.485 (3)	C7—C8	1.520 (3)
C1—C2	1.364 (4)	C7—H7A	0.97
C1—H1	0.93	C7—H7B	0.97
C2—C3	1.370 (4)	C8—C9	1.518 (3)
C2—H2	0.93	C8—H8A	0.97
C3—C4	1.366 (4)	C8—H8B	0.97
C3—H3	0.93	C9—C9^i	1.518 (4)
C4—C5	1.364 (3)	C9—H9A	0.97
C4—H4	0.93	C9—H9B	0.97
C5—H5	0.93	O1W—H1WA	0.84
C6—C7	1.509 (3)	O1W—H1WB	0.81
C1—N1—C5	120.42 (19)	C7—C6—H6B	108.9
C1—N1—C6	120.0 (2)	H6A—C6—H6B	107.7
C5—N1—C6	119.53 (18)	C6—C7—C8	111.07 (19)
N1—C1—C2	120.4 (2)	C6—C7—H7A	109.4
N1—C1—H1	119.8	C8—C7—H7A	109.4
C2—C1—H1	119.8	C6—C7—H7B	109.4
C1—C2—C3	119.7 (2)	C8—C7—H7B	109.4
C1—C2—H2	120.1	H7A—C7—H7B	108.0
C3—C2—H2	120.1	C9—C8—C7	113.04 (18)
C4—C3—C2	119.2 (2)	C9—C8—H8A	109.0
C4—C3—H3	120.4	C7—C8—H8A	109.0
C2—C3—H3	120.4	C9—C8—H8B	109.0
C5—C4—C3	119.4 (2)	C7—C8—H8B	109.0
C5—C4—H4	120.3	H8A—C8—H8B	107.8
C3—C4—H4	120.3	C9^i—C9—C8	113.9 (2)
N1—C5—C4	120.8 (2)	C9^i—C9—H9A	108.8
N1—C5—H5	119.6	C8—C9—H9A	108.8
C4—C5—H5	119.6	C9^i—C9—H9B	108.8
N1—C6—C7	113.42 (17)	C8—C9—H9B	108.8
N1—C6—H6A	108.9	H9A—C9—H9B	107.7
C7—C6—H6A	108.9	H1WA—O1W—H1WB	108.2
N1—C6—H6B	108.9
C5—N1—C1—C2	0.0 (3)	C3—C4—C5—N1	1.8 (4)
C6—N1—C1—C2	177.4 (2)	C1—N1—C6—C7	120.1 (2)
N1—C1—C2—C3	1.5 (4)	C5—N1—C6—C7	−62.5 (3)
C1—C2—C3—C4	−1.3 (4)	N1—C6—C7—C8	−178.7 (2)
C2—C3—C4—C5	−0.3 (4)	C6—C7—C8—C9	−179.0 (2)
C1—N1—C5—C4	−1.6 (3)	C7—C8—C9—C9^i	−177.0 (2)
C6—N1—C5—C4	−179.0 (2)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WB···Br1	0.81	2.55	3.353 (2)	173
O1W—H1WA···Br1^ii	0.84	2.57	3.392 (2)	169
C1—H1···Br1	0.93	2.82	3.596 (2)	141
C2—H2···O1W^iii	0.93	2.48	3.271 (3)	143
C5—H5···Br1^iv	0.93	2.67	3.588 (2)	168

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