Experimental and theoretical study of the structures and enthalpies of formation of the synthetic reagents 1,3-thiazolidine-2-thione and 1,3-oxazolidine-2-thione.
This paper reports an experimental and a theoretical study of the structures and standard (p(o) = 0.1 MPa) molar enthalpies of formation of the synthetic reagents 1,3-thiazolidine-2-thione [CAS 96-53-7] and 1,3-oxazolidine-2-thione [CAS 5840-81-3]. The enthalpies of combustion and sublimation were measured by rotary bomb combustion calorimetry, and the Knudsen effusion technique and gas-phase enthalpies of formation values at T = 298.15 K of (97.1 +/- 4.0) and -(74.4 +/- 4.6) kJ.mol(-1) for 1,3-thiazolidine-2-thione and 1,3-oxazolidine-2-thione, respectively, were determined. G3-calculated enthalpies of formation are in reasonable agreement with the experimental values. In the solid state, 1,3-thiazolidine-2-thione exists in two polymorphic forms (monoclinic and triclinic) and 1,3-oxazolidine-2-thione exits in the triclinic form. The isostructural nature of these compounds and comparison of their molecular and crystal structures have been analyzed. The experimental X-ray powder diffractograms have been compared with the calculated patterns from their structures for identification of the polymorphic samples used in this study. A comparison of our results with literature thermochemical and structural data for related compounds is also reported.
Roux
María Victoria
MV
Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain. victoriaroux@iqfr.csic.es
Temprado
Manuel
M
Jiménez
Pilar
P
Foces-Foces
Concepción
C
Notario
Rafael
R
Parameswar
Archana R
AR
Demchenko
Alexei V
AV
Chickos
James S
JS
Deakyne
Carol A
CA
Ludden
Alicia K
AK
Liebman
Joel F
JF