Dynamics and Orientation of Parathion Dissolved in a Discotic Nematic Lyomesophase

Alejandra Vera; Hernán Ahumada; Victor Bahamonde; Rodrigo Montecinos; Ramiro Araya-Maturana; Daniel Muñoz; Boris E. Weiss-López

doi:10.1071/CH08209

RESEARCH ARTICLE

Dynamics and Orientation of Parathion Dissolved in a Discotic Nematic Lyomesophase

Alejandra Vera ^A , Hernán Ahumada ^B , Victor Bahamonde ^A , Rodrigo Montecinos ^C , Ramiro Araya-Maturana ^D , Daniel Muñoz ^A and Boris E. Weiss-López ^A ^E

+ Author Affiliations

- Author Affiliations

^A Universidad de Chile, Facultad de Ciencias, Departamento de Química, Casilla 653, Santiago, Chile.

^B Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento Química de los Materiales Av. Lib. B. O’Higgins 3363, Santiago, Chile.

^C Universidad Andrés Bello, Facultad de Ecología y Recursos Naturales, Departamento de Ciencias Químicas, República 253, Santiago, Chile.

^D Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas, Departamento de Química Orgánica y Fisicoquímica, Casilla 233, Santiago 1, Chile.

^E Corresponding author. Email: bweiss@uchile.cl

Australian Journal of Chemistry 61(12) 968-974 https://doi.org/10.1071/CH08209
Submitted: 15 May 2008 Accepted: 25 September 2008 Published: 10 December 2008

Abstract

Parathion, an organophosphorous pesticide, presents serious hazards to the environment and health. It inhibits acetylcholinesterase, an enzyme incorporated in the cell membrane. A study on the behaviour of parathion in a lipid environment is interesting from environmental cleaning and biological perspectives. ²H NMR quadrupole splittings (Δν_Q) and longitudinal relaxation times (T₁) of parathion-d₄, dissolved in a nematic discotic lyomesophase made of tetradecyltrimethylammonium chloride/decanol (10% 1,1-dideuterodecanol)/water (0.1% D₂O)/NaCl, have been measured. Δν_Q and T₁ from DHO and 1,1-dideuterodecanol were also obtained. For a detailed understanding of the experimental results, a 19 ns molecular dynamics (MD) simulation of a bilayer fragment including three parathion molecules was calculated. Parathion is strongly attached to the aggregate and the solubilization increases the alignment of the interface components. Calculated densities show that parathion is located in the hydrophobic core, near the interface, and experiences an electrostatic interaction with the ammonium headgroups. On average, the molecule orients with the ring plane containing the bilayer normal.

Acknowledgements

The authors are pleased to acknowledge financial assistance from FONDECYT (Grant no. 1050201) and Facultad de Ciencias Universidad de Chile.

References

Dynamics and Orientation of Parathion Dissolved in a Discotic Nematic Lyomesophase

Abstract

Acknowledgements

Subscriber Login