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The structure at 150 K of a highly disordered pyrazole: 3-trifluoromethyl-5-(2-thienyl)-pyrazole |
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| Authors: | C Foces-Foces S Trofimenko C Lpez M D Santa María R M Claramunt J Elguero |
| Institution: | a Instituto Rocasolano, CSIC, Departamento de Cristalografía, Serrano 119, E-28006 Madrid, Spain b Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716-2522, USA c Departamento de Química Orgánica y Biología, Facultad de Ciencias, UNED, Senda del Rey 9, E-28040 Madrid, Spain d Instituto de Química Médica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain |
| Abstract: | The X-ray analysis at 150 K of the title compound, C18H5N2F3S, revealed disorder of the thienyl ring and the CF3 group in the two independent molecules. The disorder affecting the thienyl substituent consists of two alternative orientations, the E and Z with regard to the pyrazole ring. The tautomer present in the crystal is the 1H-3-trifluoromethyl-5-(2-thienyl)-pyrazole and NMR data and DSC experiments, both in the solid state and in solution, are discussed in the light of these results. The secondary structure consists of dimers formed by the two independent molecules linked by N–H H hydrogen bonds. |
| Keywords: | Pyrazoles Chalcogen effect Solid state NMR Trifluoromethyl derivatives |
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