(2R,2'S)-2,2'-Bi-piperidine-1,1'-diium dibromide.

The title compound, C10H22N2 (2+)·2Br(-), was synthesized via reduction of 2,2'-dipyridyl with Ni-Al alloy/KOH, followed by separation of diastereoisomers (meso and rac) by recrystallization from ethanol. Although the two bridging C atoms are optically active, these two chiral centers adopt an (S,R) configuration; thus, the title compound contains an achiral meso form of 2,2'-bi-piperidine. Both of the piperidinium rings adopt chair conformations, and the two N atoms are trans to each other; an inversion center is located in the mid-point of the central C-C bond. The conformation of the organic moiety resembles that of 1,1'-bi(cyclo-hexa-ne). The organic di-ammonium cations are linked to each other through hydrogen bonding with bromide counter-ions, each of which forms two hydrogen bonds (N-H⋯Br) with two adjacent organic cations, thus linking the latter together in sheets parallel to (100).

Related literature

For more details about synthetic and characterization methods, see: Denmark et n class="Chemical">al. (2006 ▶); Herrmann et al. (2006 ▶). For the chemistry of related complexes, see: Mikhalyova et al. (2012 ▶); Lyakin et al. (2012 ▶). For a related structure (the racemic isomer of the title compound), see: Laars et al. (2011 ▶).

Experimental

Crystal data

C10H22N2 2+·2Br−

M = 330.11

Monoclinic,

a = 17.9719 (9) Å

b = 9.7654 (5) Å

c = 7.3637 (3) Å

β = 92.134 (1)°

V = 1291.45 (11) Å3

Z = 4

Mo Kα radiation

μ = 6.25 mm−1

T = 100 K

0.55 × 0.23 × 0.10 mm

Data collection

Bruker D8 QUEST CMOS diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2012 ▶) T min = 0.13, T max = 0.57

12426 measured reflections

2155 independent reflections

1955 reflections with I > 2σ(I)

R int = 0.021

Refinement

R[F 2 > 2σ(F 2)] = 0.018

wR(F 2) = 0.045

S = 1.11

2155 reflections

70 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.88 e Å−3

Δρmin = −0.24 e Å−3

Data collection: APEX2 and Bruker Instrument Service (Bruker, 2013 ▶); cell refinement: SAIn class="Chemical">NT (Bruker, 2011 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: OLEX2.

Crystal structure: contains datablock(s) globn class="Chemical">al, I. DOI: 10.1107/S1600536813028754/zl2557sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813028754/zl2557Isup2.hkl

Additional supplementary materin class="Chemical">als: crystallographic information; 3D view; checkCIF report

C10H22N22+·2Br−	F(000) = 664
Mr = 330.11	Dx = 1.698 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 17.9719 (9) Å	Cell parameters from 8775 reflections
b = 9.7654 (5) Å	θ = 2.3–31.5°
c = 7.3637 (3) Å	µ = 6.25 mm−1
β = 92.134 (1)°	T = 100 K
V = 1291.45 (11) Å3	Plate, clear colorless
Z = 4	0.55 × 0.23 × 0.10 mm

Bruker D8 QUEST CMOS diffractometer	2155 independent reflections
Radiation source: sealed tube, Siemens KFFMO2K-90	1955 reflections with I > 2σ(I)
Curved graphite monochromator	Rint = 0.021
φ and ω scans	θmax = 31.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 2012)	h = −26→26
Tmin = 0.13, Tmax = 0.57	k = −14→12
12426 measured reflections	l = −10→10

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.018	Hydrogen site location: mixed
wR(F2) = 0.045	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	w = 1/[σ2(Fo2) + (0.0237P)2 + 0.7137P] where P = (Fo2 + 2Fc2)/3
2155 reflections	(Δ/σ)max = 0.001
70 parameters	Δρmax = 0.88 e Å−3
0 restraints	Δρmin = −0.24 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.

	x	y	z	Uiso*/Ueq
N1	0.15631 (5)	0.83374 (10)	0.52604 (14)	0.00987 (17)
H1A	0.1668 (8)	0.9229 (17)	0.500 (2)	0.012*
H1B	0.1566 (9)	0.8270 (15)	0.645 (2)	0.012*
C1	0.21196 (6)	0.73540 (11)	0.45193 (15)	0.00905 (18)
H1	0.2159	0.7519	0.3186	0.011*
C2	0.18497 (6)	0.58942 (11)	0.48165 (17)	0.0123 (2)
H2A	0.1854	0.5699	0.6136	0.015*
H2B	0.2195	0.5245	0.4249	0.015*
C3	0.10648 (6)	0.56754 (12)	0.40071 (17)	0.0136 (2)
H3A	0.0903	0.4725	0.4243	0.016*
H3B	0.1063	0.5813	0.2675	0.016*
C4	0.05255 (6)	0.66795 (12)	0.48479 (17)	0.0133 (2)
H4A	0.002	0.6545	0.4298	0.016*
H4B	0.0505	0.6505	0.6169	0.016*
C5	0.07765 (6)	0.81376 (12)	0.45314 (16)	0.0126 (2)
H5A	0.0749	0.8341	0.3213	0.015*
H5B	0.0441	0.8779	0.5144	0.015*
Br1	0.14264 (2)	0.83601 (2)	0.96230 (2)	0.01383 (5)

	U11	U22	U33	U12	U13	U23
N1	0.0097 (4)	0.0102 (4)	0.0097 (4)	−0.0001 (3)	0.0005 (3)	−0.0007 (3)
C1	0.0087 (4)	0.0093 (4)	0.0092 (4)	0.0003 (4)	0.0004 (3)	−0.0005 (4)
C2	0.0110 (5)	0.0093 (5)	0.0165 (5)	−0.0010 (4)	−0.0010 (4)	0.0000 (4)
C3	0.0104 (5)	0.0128 (5)	0.0176 (5)	−0.0025 (4)	−0.0005 (4)	−0.0009 (4)
C4	0.0095 (5)	0.0147 (5)	0.0158 (5)	−0.0018 (4)	0.0016 (4)	0.0004 (4)
C5	0.0090 (5)	0.0142 (5)	0.0144 (5)	0.0008 (4)	−0.0006 (4)	0.0002 (4)
Br1	0.01971 (7)	0.01159 (7)	0.01027 (6)	−0.00222 (4)	0.00163 (4)	−0.00018 (4)

N1—C1	1.5036 (14)	C2—H2B	0.99
N1—C5	1.5060 (15)	C3—C4	1.5260 (17)
N1—H1A	0.913 (16)	C3—H3A	0.99
N1—H1B	0.880 (18)	C3—H3B	0.99
C1—C2	1.5243 (16)	C4—C5	1.5143 (16)
C1—C1i	1.543 (2)	C4—H4A	0.99
C1—H1	1.0	C4—H4B	0.99
C2—C3	1.5259 (16)	C5—H5A	0.99
C2—H2A	0.99	C5—H5B	0.99
C1—N1—C5	114.59 (9)	C2—C3—C4	110.09 (9)
C1—N1—H1A	112.7 (10)	C2—C3—H3A	109.6
C5—N1—H1A	104.3 (10)	C4—C3—H3A	109.6
C1—N1—H1B	109.6 (10)	C2—C3—H3B	109.6
C5—N1—H1B	108.4 (11)	C4—C3—H3B	109.6
H1A—N1—H1B	106.8 (13)	H3A—C3—H3B	108.2
N1—C1—C2	109.01 (9)	C5—C4—C3	110.15 (9)
N1—C1—C1i	107.79 (11)	C5—C4—H4A	109.6
C2—C1—C1i	112.85 (11)	C3—C4—H4A	109.6
N1—C1—H1	109.0	C5—C4—H4B	109.6
C2—C1—H1	109.0	C3—C4—H4B	109.6
C1i—C1—H1	109.0	H4A—C4—H4B	108.1
C1—C2—C3	111.68 (9)	N1—C5—C4	110.36 (9)
C1—C2—H2A	109.3	N1—C5—H5A	109.6
C3—C2—H2A	109.3	C4—C5—H5A	109.6
C1—C2—H2B	109.3	N1—C5—H5B	109.6
C3—C2—H2B	109.3	C4—C5—H5B	109.6
H2A—C2—H2B	107.9	H5A—C5—H5B	108.1
C5—N1—C1—C2	−54.03 (12)	C1—C2—C3—C4	−58.25 (13)
C5—N1—C1—C1i	−176.84 (11)	C2—C3—C4—C5	58.08 (13)
N1—C1—C2—C3	54.76 (12)	C1—N1—C5—C4	55.44 (12)
C1i—C1—C2—C3	174.49 (11)	C3—C4—C5—N1	−55.86 (13)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br1ii	0.913 (16)	2.408 (16)	3.2670 (10)	156.7 (13)
N1—H1B···Br1	0.880 (18)	2.359 (18)	3.2311 (10)	170.9 (14)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Br1i	0.913 (16)	2.408 (16)	3.2670 (10)	156.7 (13)
N1—H1B⋯Br1	0.880 (18)	2.359 (18)	3.2311 (10)	170.9 (14)

Symmetry code: (i) .