2,2′-Bipyridinium(1+) bromide monohydrate

In the crystal structure of 2,2′-bipyridinium(1+) bromide monohydrate, C₁₀H₉N₂⁺·Br⁻·H₂O, the cation has a cisoid conformation with an intramolecular N—H...N hydrogen bond. The cation also forms an N—H...O hydrogen bond to an adjacent water mol­ecule, which in turn forms O—H...Br⁻ hydrogen bonds to adjacent Br⁻ anions. In this way, a chain is formed extending along the b axis. Additional interactions (C—H...Br⁻ and π–π) serve to stabilize the structure further.

S1. Comment

A number of structure determinations of the monoprotonated 2,2'-bipyridine with various counteranions have been reported in recent years [Cambridge Structural Database (July 2003 version; Allen, 2002), refcodes ZUTDAT (Bakshi et al., 1996), NOXXED01 (Kraus & Breu, 2002), YIPYEB01 (Fialho De Assis et al., 1996) and TEKLOK (Mrvoš-Sermek et al., 1996)]. The geometry of the bipyridinium(1+) cation has been discussed in considerable detail by Bakshi et al. (1996). Against this background, the structure of the title 2,2'-bipyridinium(1+) bromide salt, (I), is presented here. \sch

In (I), the cation (Fig. 1) has a cisoid conformation that is comparable with previously reported bipyridinium(1+) salts and which is in contrast with the transoid conformation found in unprotonated bipyridines] Almenningen et al., 1989; Chisholm et al., 1981 (BIPYRL03); Sengül et al., 1998 (NOFZUD); Osakada et al., 1991 (TAJBOV)], bipyridine adducts [Zakaria et al., 2002 (AFAZAI); Bowes et al., 2003 (HUSVIA)] or bipyridinium(2+) cations [Ma et al., 2000 (XEGKOJ); Linden et al., 1999 (FEQYIJ); Arulsamy et al., 1999 (MAHNUE)]. The dihedral angle between the planes of the aromatic rings in (I) is 3.4 (2)°, which is on the smaller side of values in the observed range of 1.3–19° reported by Bakshi et al. (1996). The C—N—C angle for the protonated atom N12 [123.6 (3)°] is about 6° larger than that at the unprotonated atom N22 [117.0 (3)°]. This effect has previously been attributed to the strong electron-withdrawing effect of the H atom (Bakshi et al., 1996). The distance between atoms N12 and N22 [2.626 (4) Å] is considerably shorter than that between atoms C16 and C26 [3.020 (5) Å]. The angle subtended by the cross-ring lines C14···C11 and C21···C24 is 170.55 (4)°. Similar intramolecular distances have been found in other bipyridinium(1+) cations (Bakshi et al., 1996) and are a consequence of the intramolecular N12—H12···N22 hydrogen bond (Table 1).

The cation in (I) forms an intermolecular hydrogen bond to an adjacent water molecule (Table 1 and Fig. 1), which is further hydrogen-bonded to two adjacent Br⁻ anions, so forming a chain which extends along the b axis (Figs. 1 and 2). The O···Br separations (Table 1) compare well with the mean value of 3.339 (7) Å reported by Steiner (1998). These chains of hydrogen-bonded moieties are the basic building blocks of the crystal structure and are further held together by two additional types of inter-moiety interactions. Also present are significant C—H···Br interactions (Table 1, and Figs. 1 and 2), which serve to link the ribbon chains. In addition, there are significant π–π interactions between inversion-related bipyridinium cations at (x,y,z) and (1 − x, 1 − y, 1 − z), as shown in Fig. 2. In this way, a layer of molecules is formed running parallel to the (101) plane. The centroid···centroid separation for ring C11—C16 at (x,y,z) and ring C21—C26 at (1 − x, 1 − y, 1 − z) is 3.699 (3) Å, and the perpendicular distance between the centroid of C11—C16 and the plane of C21—C26 at (1 − x, 1 − y, 1 − z) is 3.038 (3) Å. The shortest inter-atom separation is N12···C25ⁱⁱ 3.305 (5) Å.

S2. Experimental

2,2'-Bipyridinium bromide monohydrate was obtained serendipitously as a byproduct from the recrystallization of butyl tris(2-pyridyl)phosphonium bromide from hot acetone after adding hexane and cooling to 253 K.

S3. Refinement

All H atoms were first located from difference map plots, then positioned geometrically (C—H = 0.93, N—H = 0.86 and O—H = 0.80 Å) and allowed to ride on their respective parent atoms (U_iso(H) = 1.2U_eq(C,N). Please check added text. Water H atoms H1A and H1B were constrained to ride on their parent O atom using an AFIX 3 instruction.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SHELXTL (Bruker 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PLATON (Spek, 1993) and ORTEP-3 (Farrugia, 1997).

Figures

	Fig. 1. A view of (I) showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds to adjacent atoms are shown as dashed lines. [Symmetry codes (i) and (ii) are as in Table 1; symmetry code: (iii) 3/2 − x, 1/2 + y, 1/2 − z].
	Fig. 2. A view of the chain of cations, anions and water molecules running along the b axis in (I). Symmetry codes (i) and (ii) are as in Table 1.

2,2'-bipyridinium(1+) bromide monohydrate

Crystal data

C10H9N2^+·Br^−·H2O	F(000) = 512
Mr = 255.12	Dx = 1.578 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 867 reflections
a = 7.954 (6) Å	θ = 3.3–27.8°
b = 9.681 (7) Å	µ = 3.80 mm^−1
c = 14.037 (10) Å	T = 293 K
β = 96.449 (12)°	Rectangular, light brown
V = 1074.2 (13) Å^3	0.44 × 0.14 × 0.13 mm
Z = 4

Data collection

Bruker SMART 1K CCD area-detector diffractometer	2334 independent reflections
Radiation source: fine-focus sealed tube	1651 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
ω scans	θmax = 27.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→7
Tmin = 0.275, Tmax = 0.613	k = −10→12
6413 measured reflections	l = −17→17

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.102	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0494P)^2 + 0.4109P] where P = (Fo^2 + 2Fc^2)/3
2334 reflections	(Δ/σ)max = 0.001
128 parameters	Δρmax = 0.58 e Å^−3
0 restraints	Δρmin = −0.85 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	0.88477 (5)	0.52343 (4)	0.25781 (3)	0.06181 (17)
C11	0.2547 (4)	0.4065 (3)	0.4338 (2)	0.0377 (7)
N12	0.3017 (3)	0.3302 (3)	0.36156 (17)	0.0391 (6)
H12	0.3632	0.3685	0.3224	0.047*
C13	0.2581 (4)	0.1975 (3)	0.3471 (2)	0.0488 (8)
H13	0.2944	0.1492	0.2959	0.059*
C14	0.1602 (4)	0.1337 (4)	0.4078 (3)	0.0555 (9)
H14	0.1261	0.0425	0.3977	0.067*
C15	0.1136 (4)	0.2071 (4)	0.4837 (3)	0.0562 (9)
H15	0.0491	0.1645	0.5266	0.067*
C16	0.1606 (4)	0.3433 (3)	0.4976 (2)	0.0475 (8)
H16	0.1288	0.3920	0.5498	0.057*
C21	0.3148 (4)	0.5512 (3)	0.4394 (2)	0.0385 (7)
N22	0.4004 (3)	0.5893 (3)	0.36713 (18)	0.0467 (6)
C23	0.4569 (5)	0.7188 (4)	0.3679 (3)	0.0562 (9)
H23	0.5176	0.7467	0.3184	0.067*
C24	0.4308 (5)	0.8136 (4)	0.4377 (3)	0.0563 (9)
H24	0.4706	0.9036	0.4344	0.068*
C25	0.3450 (4)	0.7729 (3)	0.5120 (3)	0.0556 (9)
H25	0.3262	0.8347	0.5604	0.067*
C26	0.2864 (4)	0.6375 (3)	0.5143 (2)	0.0475 (8)
H26	0.2298	0.6063	0.5646	0.057*
O1	0.5162 (3)	0.3543 (3)	0.21922 (17)	0.0606 (6)
H1A	0.5986	0.4009	0.2324	0.077 (10)*
H1B	0.5555	0.2782	0.2227	0.077 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0823 (3)	0.0463 (2)	0.0621 (3)	−0.00775 (18)	0.0314 (2)	−0.00317 (16)
C11	0.0376 (16)	0.0390 (17)	0.0359 (15)	0.0028 (13)	0.0013 (12)	0.0019 (13)
N12	0.0423 (14)	0.0387 (14)	0.0366 (13)	−0.0027 (11)	0.0060 (11)	0.0001 (11)
C13	0.055 (2)	0.0426 (19)	0.0476 (19)	0.0001 (15)	−0.0004 (16)	−0.0069 (15)
C14	0.059 (2)	0.0400 (19)	0.067 (2)	−0.0115 (16)	0.0016 (18)	−0.0010 (17)
C15	0.057 (2)	0.051 (2)	0.063 (2)	−0.0096 (16)	0.0170 (17)	0.0060 (17)
C16	0.0513 (19)	0.0473 (19)	0.0465 (19)	−0.0017 (15)	0.0166 (15)	−0.0020 (15)
C21	0.0391 (16)	0.0362 (17)	0.0387 (16)	0.0002 (12)	−0.0025 (13)	0.0020 (13)
N22	0.0560 (16)	0.0434 (16)	0.0409 (14)	−0.0088 (13)	0.0069 (12)	0.0008 (12)
C23	0.068 (2)	0.050 (2)	0.050 (2)	−0.0148 (17)	0.0006 (17)	0.0100 (17)
C24	0.062 (2)	0.0383 (19)	0.064 (2)	−0.0066 (16)	−0.0136 (18)	0.0027 (17)
C25	0.062 (2)	0.0401 (19)	0.062 (2)	0.0047 (16)	−0.0043 (18)	−0.0138 (17)
C26	0.0518 (19)	0.0430 (18)	0.0471 (19)	0.0054 (15)	0.0024 (15)	−0.0052 (15)
O1	0.0722 (16)	0.0474 (15)	0.0652 (16)	0.0019 (12)	0.0210 (13)	0.0003 (12)

Geometric parameters (Å, º)

C11—N12	1.341 (4)	C21—N22	1.336 (4)
C11—C16	1.374 (4)	C21—C26	1.381 (4)
C11—C21	1.480 (4)	N22—C23	1.331 (4)
N12—C13	1.340 (4)	C23—C24	1.375 (5)
N12—H12	0.86	C23—H23	0.93
C13—C14	1.365 (5)	C24—C25	1.367 (5)
C13—H13	0.93	C24—H24	0.93
C14—C15	1.366 (5)	C25—C26	1.392 (5)
C14—H14	0.93	C25—H25	0.93
C15—C16	1.379 (5)	C26—H26	0.93
C15—H15	0.93	O1—H1A	0.80
C16—H16	0.93	O1—H1B	0.80
N12—C11—C16	117.8 (3)	N22—C21—C26	123.5 (3)
N12—C11—C21	116.5 (3)	N22—C21—C11	114.2 (3)
C16—C11—C21	125.7 (3)	C26—C21—C11	122.3 (3)
C13—N12—C11	123.6 (3)	C23—N22—C21	117.0 (3)
C13—N12—H12	118.2	N22—C23—C24	123.8 (3)
C11—N12—H12	118.2	N22—C23—H23	118.1
N12—C13—C14	119.7 (3)	C24—C23—H23	118.1
N12—C13—H13	120.2	C25—C24—C23	118.7 (3)
C14—C13—H13	120.2	C25—C24—H24	120.7
C13—C14—C15	118.4 (3)	C23—C24—H24	120.7
C13—C14—H14	120.8	C24—C25—C26	119.0 (3)
C15—C14—H14	120.8	C24—C25—H25	120.5
C14—C15—C16	121.0 (3)	C26—C25—H25	120.5
C14—C15—H15	119.5	C21—C26—C25	118.0 (3)
C16—C15—H15	119.5	C21—C26—H26	121.0
C11—C16—C15	119.5 (3)	C25—C26—H26	121.0
C11—C16—H16	120.2	H1A—O1—H1B	101.5
C15—C16—H16	120.2
C16—C11—N12—C13	1.8 (4)	N12—C11—C21—C26	−175.0 (3)
C21—C11—N12—C13	179.7 (3)	C16—C11—C21—C26	2.7 (5)
C11—N12—C13—C14	0.2 (5)	C26—C21—N22—C23	−1.4 (5)
N12—C13—C14—C15	−1.8 (5)	C11—C21—N22—C23	179.6 (3)
C13—C14—C15—C16	1.5 (5)	C21—N22—C23—C24	−0.6 (5)
N12—C11—C16—C15	−2.1 (5)	N22—C23—C24—C25	1.5 (6)
C21—C11—C16—C15	−179.8 (3)	C23—C24—C25—C26	−0.4 (5)
C14—C15—C16—C11	0.5 (5)	N22—C21—C26—C25	2.4 (5)
N12—C11—C21—N22	4.0 (4)	C11—C21—C26—C25	−178.7 (3)
C16—C11—C21—N22	−178.3 (3)	C24—C25—C26—C21	−1.4 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N12—H12···N22	0.86	2.24	2.626 (4)	107
N12—H12···O1	0.86	2.00	2.779 (4)	150
O1—H1A···Br1	0.80	2.56	3.349 (3)	171
O1—H1B···Br1^i	0.80	2.52	3.306 (3)	167
C16—H16···Br1^ii	0.93	2.84	3.723 (4)	160

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