organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

4-(2-Nitro­benzene­sulfonamido)pyri­dinium tri­fluoro­acetate

aSchool of Chemical & Biological Engineering, Changsha University of Science and Technology, Changsha 410076, People's Republic of China, bCollege of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, People's Republic of China, and cHunan Research Institute of the Chemical Industry, Changsha 410007, People's Republic of China
*Correspondence e-mail: jansenlee1103@yahoo.com.cn

(Received 1 July 2008; accepted 5 July 2008; online 12 July 2008)

In the title compound, C11H10N3O4S+·C2F3O2, the dihedral angle between the benzene ring and the pyridinium ring is 88.7 (4)°. In the crystal structure, a network of N—H⋯O, C—H⋯O and C—H⋯F hydrogen bonds links the constituent ions. One O atom of the nitro group is disordered over two positions, with site-occupancy factors of 0.57 (2) and 0.43 (2).

Related literature

For related structures, see: Yu & Li (2007[Yu, H.-J. & Li, J.-S. (2007). Acta Cryst. E63, o3399.]); Li et al. (2008[Li, J.-S., Yang, D.-W. & Liu, W.-D. (2008). Acta Cryst. E64, o204.]).

[Scheme 1]

Experimental

Crystal data
  • C11H10N3O4S+·C2F3O2

  • Mr = 393.30

  • Monoclinic, P c

  • a = 10.666 (3) Å

  • b = 5.0619 (16) Å

  • c = 14.848 (5) Å

  • β = 92.823 (6)°

  • V = 800.7 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.27 mm−1

  • T = 294 (2) K

  • 0.50 × 0.40 × 0.14 mm

Data collection
  • Bruker SMART 1K CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.875, Tmax = 0.963

  • 3878 measured reflections

  • 1912 independent reflections

  • 1351 reflections with I > 2σ(I)

  • Rint = 0.043

Refinement
  • R[F2 > 2σ(F2)] = 0.050

  • wR(F2) = 0.146

  • S = 1.01

  • 1912 reflections

  • 252 parameters

  • 44 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.40 e Å−3

  • Δρmin = −0.28 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 515 Friedel pairs

  • Flack parameter: 0.2 (2)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2⋯O6i 0.92 (8) 1.93 (9) 2.835 (8) 169 (7)
N1—H1A⋯O6 0.90 (6) 1.89 (3) 2.746 (8) 157 (7)
C3—H3⋯O1ii 0.93 2.41 3.310 (9) 162
C10—H10⋯F3iii 0.93 2.50 3.313 (12) 146
Symmetry codes: (i) [x, -y+1, z+{\script{1\over 2}}]; (ii) [x, -y+2, z-{\script{1\over 2}}]; (iii) [x-1, -y, z+{\script{1\over 2}}].

Data collection: SMART (Bruker, 1997[Bruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 1997[Bruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

The title compound, (I), comprises of pyridinium cation and a trifluoroacetate anion (Fig. 1). In the cation, the short C—N distance [C1—N2 = 1.383 (9) Å] and planar conformation [C1—N2—S1 = 126.8 (5)°, C1—N2—-H2 = 114 (5)°, S1—N2—H2 = 119 (5)°] indicate that N2 possesses sp2 character despite the proximity of the strongly electron-withdrawing sulfonyl group. The benzene ring makes an angle of 88.7 (4)° with the pyridinium ring.

A network of intermolecular N—H···O, C—H···O and C—H···F hydrogen bonds (Table 1) complete the crystal packing for (I).

For related structures, see: Yu & Li (2007) and Li et al. (2008).

Related literature top

For related structures, see: Yu & Li (2007); Li et al. (2008).

Experimental top

2-Nitro-(N-pyridyl)benzenesulfonamide was prepared by the method of Yu & Li (2007). Colourless blocks of (I) were grown by natural evaporation of a methanolic solution of the amide trifluoroacetate salt.

Refinement top

The N-bound H atoms were located in a difference map and refined with the restraint N—H = 0.90 (1)Å. and the C-bound H atoms were positioned geometrically (C—H = 0.93 Å) and refined as riding atoms. The constraint Uĩso~(H) = 1.2 U~eq~(C and N) was applied.

The C—F distances in the anion were restrained to 1.36 (1) Å and the N3—O4(O4') distances to 1.20 (1) Å. The displacement parameters for the F atoms and O4/O4' were restrained to approximate to isotropic behaviour. The nitro group is partially disordered over two positions in a 0.57 (2):0.43 (2) ratio.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of (I) with displacement ellipsoids drawn at the 50% probability level (arbitrary spheres for the H atoms). Only the major disordered nitro group is shown. The dashed line indicates the H-bond.
4-(2-Nitrobenzenesulfonamido)pyridinium trifluoroacetate top
Crystal data top
C11H10N3O4S+·C2F3O2F(000) = 400
Mr = 393.30Dx = 1.631 Mg m3
Monoclinic, PcMo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2ycCell parameters from 903 reflections
a = 10.666 (3) Åθ = 2.8–21.0°
b = 5.0619 (16) ŵ = 0.27 mm1
c = 14.848 (5) ÅT = 294 K
β = 92.823 (6)°Block, colourless
V = 800.7 (4) Å30.50 × 0.40 × 0.14 mm
Z = 2
Data collection top
Bruker SMART 1K CCD
diffractometer
1912 independent reflections
Radiation source: fine-focus sealed tube1351 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.043
ω scansθmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 612
Tmin = 0.875, Tmax = 0.963k = 66
3878 measured reflectionsl = 1717
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difmap and geom
R[F2 > 2σ(F2)] = 0.050H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.146 w = 1/[σ2(Fo2) + (0.0892P)2 + 0.0881P]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max < 0.001
1912 reflectionsΔρmax = 0.40 e Å3
252 parametersΔρmin = 0.28 e Å3
44 restraintsAbsolute structure: Flack (1983), 515 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.2 (2)
Crystal data top
C11H10N3O4S+·C2F3O2V = 800.7 (4) Å3
Mr = 393.30Z = 2
Monoclinic, PcMo Kα radiation
a = 10.666 (3) ŵ = 0.27 mm1
b = 5.0619 (16) ÅT = 294 K
c = 14.848 (5) Å0.50 × 0.40 × 0.14 mm
β = 92.823 (6)°
Data collection top
Bruker SMART 1K CCD
diffractometer
1912 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1351 reflections with I > 2σ(I)
Tmin = 0.875, Tmax = 0.963Rint = 0.043
3878 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.050H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.146Δρmax = 0.40 e Å3
S = 1.01Δρmin = 0.28 e Å3
1912 reflectionsAbsolute structure: Flack (1983), 515 Friedel pairs
252 parametersAbsolute structure parameter: 0.2 (2)
44 restraints
Special details top

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 (Å2) top
xyzUiso*/UeqOcc. (<1)
S10.1917 (2)1.1065 (3)0.30158 (15)0.0475 (5)
O10.2002 (5)1.2527 (9)0.3840 (4)0.0618 (16)
O20.1765 (5)1.2424 (10)0.2190 (4)0.0606 (16)
O30.2046 (5)0.7895 (10)0.4739 (3)0.0585 (14)
O40.0306 (13)0.694 (4)0.5333 (8)0.100 (5)0.57 (2)
O4'0.0360 (16)0.896 (5)0.5277 (10)0.092 (6)0.43 (2)
N10.4391 (6)0.4397 (12)0.1006 (4)0.0510 (15)
H1A0.461 (7)0.307 (10)0.064 (4)0.061*
N20.3191 (6)0.9262 (13)0.3012 (4)0.0483 (17)
H20.364 (8)0.898 (14)0.355 (6)0.058*
N30.0922 (7)0.7742 (19)0.4702 (4)0.077 (2)
C10.3581 (6)0.7718 (13)0.2310 (4)0.0392 (17)
C20.3127 (7)0.7987 (13)0.1424 (5)0.0464 (19)
H2A0.25370.92800.12650.056*
C30.3570 (7)0.6291 (14)0.0778 (5)0.049 (2)
H30.32890.64790.01790.059*
C40.4851 (7)0.4122 (14)0.1858 (5)0.0486 (17)
H40.54390.28110.19990.058*
C50.4461 (7)0.5751 (13)0.2515 (5)0.0404 (17)
H50.47830.55500.31040.048*
C60.0662 (6)0.8823 (12)0.3040 (4)0.0367 (17)
C70.0026 (8)0.8267 (15)0.2243 (5)0.059 (2)
H70.02000.90970.17160.071*
C80.1003 (8)0.6585 (19)0.2199 (6)0.074 (3)
H80.14320.62660.16490.088*
C90.1370 (8)0.533 (2)0.2967 (7)0.075 (3)
H90.20490.41810.29390.090*
C100.0735 (8)0.5798 (19)0.3759 (6)0.067 (3)
H100.09770.49540.42800.081*
C110.0259 (7)0.7498 (16)0.3802 (5)0.050 (2)
F10.6379 (6)0.0984 (15)0.0885 (4)0.120 (2)
F20.7133 (6)0.2337 (12)0.0429 (5)0.112 (2)
F30.7883 (6)0.1131 (15)0.0079 (5)0.126 (2)
O50.6055 (6)0.1151 (14)0.1338 (5)0.104 (2)
O60.4859 (5)0.1277 (10)0.0453 (3)0.0544 (13)
C120.5818 (7)0.0001 (15)0.0642 (5)0.0535 (19)
C130.6817 (7)0.0063 (15)0.0123 (5)0.062 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0514 (10)0.0362 (8)0.0533 (10)0.0036 (10)0.0129 (7)0.0053 (10)
O10.075 (4)0.041 (3)0.067 (4)0.003 (3)0.021 (3)0.023 (3)
O20.069 (4)0.052 (3)0.060 (4)0.003 (3)0.012 (3)0.017 (3)
O30.055 (4)0.067 (3)0.051 (3)0.006 (3)0.018 (3)0.003 (2)
O40.095 (8)0.148 (11)0.060 (7)0.011 (7)0.019 (6)0.015 (7)
O4'0.084 (9)0.136 (11)0.055 (8)0.005 (8)0.013 (6)0.020 (8)
N10.059 (4)0.054 (4)0.040 (4)0.007 (3)0.001 (3)0.001 (3)
N20.045 (4)0.053 (4)0.045 (4)0.005 (3)0.011 (3)0.001 (3)
N30.055 (5)0.138 (8)0.037 (4)0.010 (5)0.000 (4)0.010 (4)
C10.040 (4)0.036 (4)0.041 (4)0.012 (3)0.009 (3)0.003 (3)
C20.057 (5)0.040 (4)0.041 (4)0.011 (4)0.013 (3)0.006 (3)
C30.053 (5)0.059 (5)0.035 (4)0.011 (4)0.010 (3)0.004 (4)
C40.047 (4)0.055 (4)0.042 (4)0.006 (4)0.005 (3)0.005 (3)
C50.040 (4)0.043 (4)0.038 (4)0.002 (3)0.008 (3)0.002 (3)
C60.039 (4)0.039 (4)0.030 (4)0.013 (3)0.010 (3)0.004 (3)
C70.056 (5)0.074 (5)0.045 (4)0.010 (4)0.010 (4)0.005 (4)
C80.062 (6)0.098 (7)0.060 (5)0.022 (5)0.017 (4)0.007 (5)
C90.052 (5)0.084 (6)0.088 (7)0.011 (5)0.009 (5)0.006 (5)
C100.050 (5)0.086 (6)0.067 (6)0.000 (5)0.007 (5)0.017 (5)
C110.041 (5)0.070 (5)0.038 (4)0.013 (4)0.002 (4)0.002 (4)
F10.093 (4)0.181 (6)0.085 (4)0.005 (5)0.022 (3)0.034 (4)
F20.093 (4)0.115 (4)0.125 (4)0.013 (4)0.031 (3)0.034 (4)
F30.074 (4)0.160 (5)0.140 (5)0.047 (4)0.020 (3)0.042 (4)
O50.081 (5)0.141 (6)0.087 (5)0.033 (4)0.013 (4)0.066 (4)
O60.048 (3)0.068 (3)0.046 (3)0.013 (3)0.012 (2)0.007 (2)
C120.050 (5)0.051 (4)0.058 (5)0.002 (4)0.004 (4)0.005 (4)
C130.054 (6)0.067 (5)0.065 (5)0.009 (5)0.002 (4)0.004 (4)
Geometric parameters (Å, º) top
S1—O21.408 (6)C4—H40.9300
S1—O11.429 (5)C5—H50.9300
S1—N21.637 (7)C6—C71.390 (9)
S1—C61.757 (7)C6—C111.401 (10)
O3—N31.200 (8)C7—C81.345 (11)
O4—N31.239 (9)C7—H70.9300
O4'—N31.233 (10)C8—C91.378 (13)
N1—C31.331 (9)C8—H80.9300
N1—C41.341 (9)C9—C101.349 (12)
N1—H1A0.90 (6)C9—H90.9300
N2—C11.383 (9)C10—C111.365 (11)
N2—H20.92 (8)C10—H100.9300
N3—C111.485 (10)F1—C131.328 (7)
C1—C21.387 (9)F2—C131.334 (7)
C1—C51.391 (10)F3—C131.308 (8)
C2—C31.387 (10)O5—C121.223 (10)
C2—H2A0.9300O6—C121.253 (9)
C3—H30.9300C12—C131.520 (11)
C4—C51.358 (9)
O2—S1—O1119.5 (3)C4—C5—C1120.3 (7)
O2—S1—N2109.2 (4)C4—C5—H5119.8
O1—S1—N2105.9 (3)C1—C5—H5119.8
O2—S1—C6106.1 (3)C7—C6—C11114.9 (7)
O1—S1—C6109.5 (3)C7—C6—S1118.9 (5)
N2—S1—C6105.9 (3)C11—C6—S1126.2 (5)
C3—N1—C4121.3 (7)C8—C7—C6123.0 (7)
C3—N1—H1A125 (5)C8—C7—H7118.5
C4—N1—H1A113 (5)C6—C7—H7118.5
C1—N2—S1126.8 (5)C7—C8—C9120.1 (8)
C1—N2—H2114 (5)C7—C8—H8120.0
S1—N2—H2119 (5)C9—C8—H8120.0
O3—N3—O4'117.1 (12)C10—C9—C8119.4 (9)
O3—N3—O4123.5 (10)C10—C9—H9120.3
O4'—N3—O449.2 (9)C8—C9—H9120.3
O3—N3—C11118.5 (6)C9—C10—C11120.4 (9)
O4'—N3—C11116.0 (11)C9—C10—H10119.8
O4—N3—C11114.0 (10)C11—C10—H10119.8
N2—C1—C2123.7 (7)C10—C11—C6122.2 (7)
N2—C1—C5117.7 (6)C10—C11—N3115.4 (8)
C2—C1—C5118.6 (7)C6—C11—N3122.4 (7)
C1—C2—C3118.7 (7)O5—C12—O6129.9 (7)
C1—C2—H2A120.7O5—C12—C13117.0 (7)
C3—C2—H2A120.7O6—C12—C13113.1 (7)
N1—C3—C2120.9 (7)F3—C13—F1113.4 (8)
N1—C3—H3119.6F3—C13—F2104.3 (7)
C2—C3—H3119.6F1—C13—F297.1 (7)
N1—C4—C5120.2 (7)F3—C13—C12115.0 (7)
N1—C4—H4119.9F1—C13—C12112.4 (7)
C5—C4—H4119.9F2—C13—C12113.0 (7)
O2—S1—N2—C143.3 (7)C6—C7—C8—C90.5 (14)
O1—S1—N2—C1173.2 (6)C7—C8—C9—C100.5 (14)
C6—S1—N2—C170.6 (7)C8—C9—C10—C110.2 (14)
S1—N2—C1—C217.6 (10)C9—C10—C11—C60.0 (13)
S1—N2—C1—C5161.0 (5)C9—C10—C11—N3177.0 (8)
N2—C1—C2—C3178.8 (6)C7—C6—C11—C100.1 (11)
C5—C1—C2—C30.2 (10)S1—C6—C11—C10179.5 (6)
C4—N1—C3—C22.3 (10)C7—C6—C11—N3176.8 (7)
C1—C2—C3—N11.6 (10)S1—C6—C11—N33.6 (10)
C3—N1—C4—C51.5 (10)O3—N3—C11—C10140.3 (8)
N1—C4—C5—C10.0 (10)O4'—N3—C11—C1072.6 (16)
N2—C1—C5—C4178.1 (6)O4—N3—C11—C1017.9 (15)
C2—C1—C5—C40.6 (10)O3—N3—C11—C636.8 (12)
O2—S1—C6—C715.4 (6)O4'—N3—C11—C6110.3 (16)
O1—S1—C6—C7145.6 (6)O4—N3—C11—C6165.0 (13)
N2—S1—C6—C7100.6 (6)O5—C12—C13—F36.6 (11)
O2—S1—C6—C11164.2 (6)O6—C12—C13—F3173.1 (7)
O1—S1—C6—C1134.0 (7)O5—C12—C13—F1125.1 (9)
N2—S1—C6—C1179.8 (7)O6—C12—C13—F155.2 (9)
C11—C6—C7—C80.2 (12)O5—C12—C13—F2126.1 (9)
S1—C6—C7—C8179.8 (7)O6—C12—C13—F253.5 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···O6i0.92 (8)1.93 (9)2.835 (8)169 (7)
N1—H1A···O60.90 (6)1.89 (3)2.746 (8)157 (7)
C3—H3···O1ii0.932.413.310 (9)162
C10—H10···F3iii0.932.503.313 (12)146
Symmetry codes: (i) x, y+1, z+1/2; (ii) x, y+2, z1/2; (iii) x1, y, z+1/2.

Experimental details

Crystal data
Chemical formulaC11H10N3O4S+·C2F3O2
Mr393.30
Crystal system, space groupMonoclinic, Pc
Temperature (K)294
a, b, c (Å)10.666 (3), 5.0619 (16), 14.848 (5)
β (°) 92.823 (6)
V3)800.7 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.27
Crystal size (mm)0.50 × 0.40 × 0.14
Data collection
DiffractometerBruker SMART 1K CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.875, 0.963
No. of measured, independent and
observed [I > 2σ(I)] reflections
3878, 1912, 1351
Rint0.043
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.146, 1.01
No. of reflections1912
No. of parameters252
No. of restraints44
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.40, 0.28
Absolute structureFlack (1983), 515 Friedel pairs
Absolute structure parameter0.2 (2)

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···O6i0.92 (8)1.93 (9)2.835 (8)169 (7)
N1—H1A···O60.90 (6)1.89 (3)2.746 (8)157 (7)
C3—H3···O1ii0.932.413.310 (9)162
C10—H10···F3iii0.932.503.313 (12)146
Symmetry codes: (i) x, y+1, z+1/2; (ii) x, y+2, z1/2; (iii) x1, y, z+1/2.
 

References

First citationBruker (1997). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationLi, J.-S., Yang, D.-W. & Liu, W.-D. (2008). Acta Cryst. E64, o204.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationYu, H.-J. & Li, J.-S. (2007). Acta Cryst. E63, o3399.  CSD CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds