Bol. Soc. Chil. Quím., 47, 159-162 (2002)

Iván Brito*¹, Yasna León¹, Mauricio Arias¹, Danitza Vargas¹, Francisco
Carmona¹, Eduardo Ramírez¹, Ambrosio Restovic¹, Alejandro Cárdenas¹

¹Facultad de Ciencias Básicas, Universidad de Antofagasta, casilla 170, Antofagasta, Chile
Oscar Wittke^2
2Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, casilla 487-3, Santiago, Chile.
Matías López-Rodríguez^3
3Centro de Productos Naturales Orgánicos "Antonio González", Instituto Universitario de
Bio-Orgánica. Universidad de La Laguna, Astrofísico Francisco Sánchez N 2 La Laguna, Tenerife, Spain.
Received: September 24,2001 - Accepted: March 4, 2002)

SUMMARY

The crystal and molecular structure of 5-nitropiridine piperidine-sulfenamide, C₁₀H₁₃N₃O₂ S is described and compared with other sulfenamides and with other similar compounds. This structure belongs to a type of divalent sulphur compound and crystallizes in the orthorhombic space group Pnma with a= 27.810(4), b=6.797(1), c=6.110(1)Å, and Dx =1.376 g cm^-3 with Z=4. The S-N bond distance of 1.699(4) Å is shorter than a single S-N bond [1.74 Å]. The NO₂-(C₆H₃N)-S-N(C ₅H₁₀) molecule lies on a crystallographic mirror plane.

KEY WORDS: Sulfenamides, sulfenic acid derivatives, divalent sulfur compounds

RESUMEN

Se describe la estructura cristalina y molecular de 5-nitropiridina piperidina-sulfenamida C₁₀H₁₃N₃O₂ S y se compara con otras sulfenamidas y con otros compuestos similares. Esta estructura pertenece a un tipo de compuestos de azufre divalente y cristaliza en el sistema ortorrómbico, grupo espacial Pnma con a= 27.810(4), b=6.797(1), c=6.110(1)Å, y Dx =1.376 g cm^-3 con Z=4. La distancia de enlace S-N de 1.699(4) Å es mas corta que un enlace simple S-N [1.74 Å]. La molécula NO₂-(C₆H₃N)-S-N(C ₅H₁₀) queda en un plano de espejo cristalográfico.

PALABRAS CLAVES : sulfenamidas, derivados de ácidos sulfénicos, compuestos de azufre divalente.

INTRODUCTION

Sulfenamides are important intermediates in organic synthesis and have proven useful in investigations of lone pair interactions (a effect), bond polarization effects, and (p-d) p conjugation^1-3). Industrial applications of sulfenamide derivatives include use as accelerators in rubber vulcanization, pesticides and fungicides, radioprotective agents, and in polymerization reactions⁴⁾. Accordingly and in view of our continuous interest in the synthesis, characterization and crystal structure of sulfenamides^5-9) , we report here the crystal and molecular structure of a novel sulfenamide. The crystal structure can be described in term of discrete molecules with one independent molecules in the asymmetric unit.

EXPERIMENTAL

Synthesis was carried out by reaction of 0.046 mol of (NO₂-C₆H₃NS)₂ and 0.23 mol of (NHC₅H₁₀) in methanol for 12h at ­18C, using the metal-assisted technique¹⁰⁾. The title compound was crystallized by slow evaporation from diethylether. A single crystal with dimension 0.05x0.06x0.05 mm was used for measurements on a Siemens R3m diffractometer , Mo Ka radiation, w:/2q scan mode. The lattice constants were obtained from least squares refinement of 30 reflections in the interval 8 <q<12.5 Of the 1547 data measured with 3<q<27.6, 726 data having F³2s(F), (index range h=-30®36, k=-8®6, l=-7®7) were considered observed and used for the structure determination and refinement. The title structure was solved by direct methods and completed by difference Fourier. It was refined by full-matrix least squares ^11-12). All H atoms were located by a difference Fourier synthesis and refined with fixed individual displacement parameters [U(H)=1.2 Ueq(C)] using a riding model with C-H (aromatic)=0.93, C-H (secondary)=0.97 Å. Refinement converged to R=0.051, R_w=0.151, S=0.785 for 92 refined parameters. Geometrical calculations were made with PARST ¹³⁾.

RESULTS AND DISCUSSION

Table I gives the atomic coordinates and equivalent isotropic displacement parameters for all non-H atoms. The molecular structure of the title compound including the atom-numbering scheme is illustrated in Fig. 1. The packing in the unit cell viewed down the c axis, showing the hydrogen-bonding interactions as broken lines is illustrated in Fig. 2. Table II shows selected geometric parameters. The compound crystallizes in the orthorhombic space group Pnma, the molecule occupying a special position on the crystallographic mirror plane. The nitropiridine fragment and S, N3 and C8 atoms, lie in that plane. The piperidine ring exhibits a chair conformation as shown by the ring puckering parameters¹⁴⁾: Q=1.912(4) Å; q=170.3(1) and j=271.8(7). Bond lengths and angles for this fragment are in the usual range compared with similar structures retrieved from the Cambridge Structural Database¹⁵⁾ (version 5.21, April 2001). The fragment nitropiridine is planar. The bonds between the non-substituted aromatic C atoms are significantly shortened compared with the other aromatic bonds; such effect is similar in: 5-nitro-2-(2-pyridinylthio)pyridine¹⁶⁾ and bis (5-nitropyridine-2-thiolato)-bis-(n-butyl)-tin(IV) ¹⁷⁾. The sum of the angles about atom N₁ [359.9(4)]reflects a planar sp² geometry . The mean N-O bond lengths are in the usual range [1.224(5)-1.230(4) Å] for aromatic NO₂ groups and compare well with data available for such systems^18-19). The S-N distance of 1.699(4) Å is in agreement with the value of 1.695(4) Å reported for Triphenylmethane-piperidine-sulfenamida and it is consistent with previously observed S-N single bonds exhibing p character^1,5-9,21). It is significantly larger than the value 1.668(5) Å reported for 2-Tricloromethylthio-1-H-isoindole-1,3(2H)-dione ²⁰⁾, but it is smaller than the value 1.765(3) given as characteristic of RS-X₂ bonds involving pyramidal N atoms²²⁾. The C-S bond distance, 1.760(4)Å, agrees with the value 1.765(3)Å reported for (N,N-dicyclohexyl)benzenesulfenamide [1.684(3)Å]⁶⁾ but it is significantly smaller than the values reported for triphenylmethanesulfenamide [1.873(2)Å]²²⁾, triphenylmethane-piperidine-sulfenamide [1.901(4)Å]Å, and larger than the values reported for N,N-dibenzylbencenesulfenamide [1.738(10)Å]⁸⁾ .The molecule is in the torsional fundamental state.

The structure is stabilized by weak intermolecular C-H..O interactions [ C3-H3 0.93, H3.O1ⁱ 2.54 , C3O1ⁱ 3.332(2) Å and C3-H3O1ⁱ 143.4 symmetry code: (i) x,-y+1/2, z+1] in addition to van der Waals forces.

FIG. 1. A molecular view of the title compuond with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

FIG. 2. The crystal structure of the title compound, with the hydrogen-bonding scheme shown as dashed lines.

ACKNOWLEDGEMENTS

IB thanks DGI (Universidad de Antofagasta). Data collection was performed at the Universidad de Chile on a single-crystal diffractometer purchased by Fundación Andes.

REFERENCES

1. L. Craine & M. Raban. Chem. Rev. 89, 689 (1989).

2. M. Makosza & M.Bialecki. J.Org.Chem. 63:15, 4878 (1988).

3. M.B-D.Blanca, E.Maimon & D.Kost. Angew.Chem.Int.Ed.Engl. 36:20,2216(1997).

4. C.Brown & B.T. Grayson, Mech.React.Sulfur Compd., 5, 93 (1970).

5. M.L. Rodríguez, C. Ruiz-Pérez, I. Brito, C. Díaz, J. Cuevas, G. González & V. Manríquez. J.Organomet.Chem. 377, 235 (1989).

6 M.L .Rodríguez, I. Brito, C. Díaz, J. Cuevas, G. González & V. Manríquez, J.Organomet.Chem. 425, 49 (1992).

7. C. Díaz, V. Manríquez, G. González, I. Brito & M.L. Rodríguez. Bol.Soc.Chil.Quím. 38, 83 (1993).

8. I. Brito, C. Díaz, G. González, M.L. Rodríguez & V. Manriquez. Bol. Soc. Chil.Quím., 44, 459 (1999).

9. I. Brito, Y. León, C. Gacitua, M. Arias, J. Ponce, O. Wittke, M.L. Rodríguez. Bol.Soc.Chil. Quim. 45, 509 (2000).

10. F.A. Davis, A.J. Friedman, E.W. Kluger, E.B. Skibo, E.R. Fretz, A.P. Milicia, W.C. LeMasters. J.Org.Chem. 42, 967 (1977).

11. G.M Sheldrick. SHELXS86. Program for crystal structure determination, University of Göttingen, Germany (1986).

12. G.M. Sheldrick. SHELXL93. Program for refinement of crystal structures. University of Göttingen, Germany (1993).

13. M. Nardelli. Comp.Chem., 7, 95 (1983).

14. D. Cremer, & J.A. Pople. J. Am.Chem.Soc. 97, 1354 (1975).

15. F.H. Allen & O. Kennard. Chem.Des.Autom.News, 8, 1, 31 (1993).

16. M.E. Amato, G. Bandoli, A. Grossi, G.C. Pappalardo &G.Scarlata. Phosphorus, Sulfur and Silicon Relat. Elem. 45, 197 (1989).

17. G.Domazetis, B.D. James, M.F. Mackay, R.J. Magee. J. Inor. Nucl.Chem., 41, 1555, (1979).

18. D.D. MacNicol & P.R. Mallinson. Acta Cryst. C51, 926, (1995).

19. L.Y. Hsu, C.E. Nordman & D.H. Kenny. Acta Cryst. C49, 394 (1993).

20. A. Björn Carle, Jeannette A. Krause Bauer & R.Marshall Wilson. Acta Cryst. C56, 97, (2000).

21. F. Iwasaki & Y. Masuko. Acta Cryst. C42, 124 (1986).

22. S. Auricchio, S. Brückner, L. Malpezzi Giunchi, V.A. Kozinsky, & O.V. Zelenskaja. J.Heterocycl.Chem. 17, 1217 (1980).