4-Ammonio-benzamidinium dichloride.

The crystal structure of the title compound, C(7)H(11)N(3) (2+)·2Cl(-), has been determined as part of a project focusing on the ability of the benzamidine system to form strong hydrogen bonds in aqueous media. It is commonly used as a ligand in affinity chromatography for purification and immobilization of enzymes. A twofold rotation axis runs along the axis of the cation. The orientation of the amidinium group with respect to the benzene ring is indicated by the N-C-C-C torsion angle of 40.2 (1)°. In the crystal structure, cations and anions are linked via hydrogen bonds. The chloride anion is surrounded by four ammonium cations in a tetra-hedral environment. The aromatic rings of the amidinium cations are π-stacked, with a centroid-centroid distance of 4.178 (1) Å.

Related literature

For related literature, see: Boyd (1991 ▶); Nguyen & Loung (1990 ▶); Jarak et al. (2005 ▶); Hranjec et al. (2003 ▶); Danan et al. (1997 ▶); Del Poeta, Schell, Dykstra, Jones, Tidwell, Czarny et al. (1998 ▶); Del Poeta, Schell, Dykstra, Jones, Tidwell, Kumar et al., (1998 ▶); Janiak (2000 ▶); Fujita et al. (1995 ▶); Müller et al. (2006 ▶); Kimata et al. (1990 ▶). For examples of related tubular superstructures, see: Barboiu et al. (2003 ▶); Blondeau et al. (2005 ▶).

Experimental

Crystal data

C7H11N3 2+·2Cl−

M = 208.09

Monoclinic,

a = 4.1779 (2) Å

b = 20.9388 (10) Å

c = 11.6260 (5) Å

β = 94.920 (4)°

V = 1013.30 (8) Å3

Z = 4

Mo Kα radiation

μ = 0.59 mm−1

T = 175 K

0.49 × 0.09 × 0.05 mm

Data collection

Oxford Diffraction XCalibur diffractometer

Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 ▶) T min = 0.95, T max = 0.97

7752 measured reflections

1750 independent reflections

1144 reflections with I > 2σ(I)

R int = 0.018

Refinement

R[F 2 > 2σ(F 2)] = 0.027

wR(F 2) = 0.034

S = 1.00

1144 reflections

59 parameters

2 restraints

H-atom parameters constrained

Δρmax = 0.34 e Å−3

Δρmin = −0.20 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SIR2004 (Burla et al., 2003 ▶); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ▶); molecular graphics: CAMERON (Watkin et al., 1996 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: CRYSTALS.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808010179/wn2252sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808010179/wn2252Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C7H11N32+·2Cl–	F000 = 432
Mr = 208.09	Dx = 1.364 Mg m−3
Monoclinic, C2/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4424 reflections
a = 4.1779 (2) Å	θ = 4–32º
b = 20.9388 (10) Å	µ = 0.59 mm−1
c = 11.6260 (5) Å	T = 175 K
β = 94.920 (4)º	Stick, colourless
V = 1013.30 (8) Å3	0.49 × 0.09 × 0.05 mm
Z = 4

Oxford Diffraction XCALIBUR diffractometer	1750 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1144 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.018
Detector resolution: 16.0143 pixels mm-1	θmax = 32.7º
T = 175 K	θmin = 3.9º
ω scans	h = −5→6
Absorption correction: multi-scan(CrysAlis RED; Oxford Diffraction, 2007); empirical (using intensity measurements) absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm	k = −31→29
Tmin = 0.95, Tmax = 0.97	l = −17→15
7752 measured reflections

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027	H-atom parameters constrained
wR(F2) = 0.034	Method, part 1, Chebychev polynomial [Watkin, D. J. (1994). Acta Cryst. A50, 411-437. Prince, E. (1982). Mathematical Techniques in Crystallography and Materials Science. New York: Springer-Verlag.] [weight] = 1.0/[A0*T0(x) + A1*T1(x) ··· + An-1]*Tn-1(x)] where Ai are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] * [1-(deltaF/6*sigmaF)2]2 Ai are 20.0 -14.7 15.4
S = 1.01	(Δ/σ)max = 0.001
1144 reflections	Δρmax = 0.34 e Å−3
59 parameters	Δρmin = −0.20 e Å−3
2 restraints	Extinction correction: None

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cl1	0.03602 (8)	0.146532 (14)	0.92627 (3)	0.0297
N2	0.0839 (4)	0.29292 (6)	0.84632 (10)	0.0380
C3	0.0000	0.32303 (8)	0.7500	0.0271
C4	0.0000	0.39368 (8)	0.7500	0.0236
C5	−0.1109 (3)	0.42664 (6)	0.84251 (11)	0.0282
C6	−0.1138 (3)	0.49282 (6)	0.84200 (11)	0.0296
C7	0.0000	0.52485 (8)	0.7500	0.0264
N8	0.000000 (10)	0.59418 (7)	0.750000 (10)	0.0381
H9	0.1600	0.3149	0.9089	0.0500*
H10	0.0659	0.2491	0.8520	0.0500*
H11	−0.1867	0.4022	0.9091	0.0500*
H12	−0.1892	0.5181	0.9058	0.0500*
H13	0.1342	0.6109	0.8006	0.0500*	0.7500
H14	−0.1333	0.6116	0.8033	0.0500*	0.7500

	U11	U22	U33	U12	U13	U23
Cl1	0.04130 (17)	0.02485 (14)	0.02214 (13)	−0.00435 (13)	−0.00233 (9)	−0.00073 (11)
N2	0.0652 (9)	0.0209 (5)	0.0252 (5)	−0.0030 (5)	−0.0122 (5)	0.0038 (4)
C3	0.0386 (9)	0.0198 (7)	0.0218 (7)	0.0000	−0.0043 (6)	0.0000
C4	0.0324 (9)	0.0184 (6)	0.0191 (6)	0.0000	−0.0030 (6)	0.0000
C5	0.0403 (7)	0.0236 (5)	0.0208 (5)	0.0006 (5)	0.0021 (4)	0.0000 (4)
C6	0.0379 (7)	0.0238 (6)	0.0265 (5)	0.0036 (5)	−0.0011 (4)	−0.0043 (4)
C7	0.0275 (8)	0.0180 (6)	0.0319 (8)	0.0000	−0.0074 (6)	0.0000
N8	0.0296 (8)	0.0177 (7)	0.0651 (12)	0.0000	−0.0072 (8)	0.0000

N2—C3	1.3064 (13)	C6—C7	1.3810 (16)
N2—H9	0.896	C6—H12	0.985
N2—H10	0.923	C7—N8	1.452 (2)
C3—C4	1.479 (2)	N8—H14i	0.942
C4—C5	1.3904 (15)	N8—H13i	0.852
C5—C6	1.3859 (18)	N8—H13	0.852
C5—H11	1.002	N8—H14	0.942
C3—N2—H9	120.0	C6—C7—N8	119.05 (8)
C3—N2—H10	121.5	C6i—C7—N8	119.05 (8)
H9—N2—H10	118.5	C7—N8—H14i	112.8
N2—C3—N2i	122.30 (16)	C7—N8—H13i	114.3
N2—C3—C4	118.85 (8)	H14i—N8—H13i	77.2
C3—C4—C5	119.75 (8)	C7—N8—H13	114.3
C5i—C4—C5	120.49 (16)	H14i—N8—H13	84.5
C4—C5—C6	119.76 (13)	H13i—N8—H13	131.5
C4—C5—H11	119.5	C7—N8—H14	112.8
C6—C5—H11	120.7	H14i—N8—H14	134.3
C5—C6—C7	119.04 (13)	H13i—N8—H14	84.5
C5—C6—H12	122.5	H13—N8—H14	77.2
C7—C6—H12	118.5
C(4)—C(5)—C(6)—C(7)	−1.2 (1)	C(5)—C(6)—C(7)—N(8)	−179.4 (1)
C(5)—C(4)—C(3)—N(2)	−40.2 (1)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H9···Cl1ii	0.90	2.35	3.2247 (13)	166
N2—H10···Cl1	0.92	2.32	3.2142 (13)	162
N8—H13···Cl1iii	0.85	2.26	3.1031 (6)	173
N8—H14···Cl1iv	0.94	2.20	3.1369 (6)	176
C5—H11···Cl1v	1.00	2.70	3.6806 (13)	165

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H9⋯Cl1i	0.90	2.35	3.2247 (13)	166
N2—H10⋯Cl1	0.92	2.32	3.2142 (13)	162
N8—H13⋯Cl1ii	0.85	2.26	3.1031 (6)	173
N8—H14⋯Cl1iii	0.94	2.20	3.1369 (6)	176
C5—H11⋯Cl1iv	1.00	2.70	3.6806 (13)	165

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .