title: Photoinduced and thermal denitrogenation of bulky triazoline crystals: insights into solid-to-solid transformation.
abstract: The photoinduced and thermal denitrogenation of crystalline triazolines with bulky substituents leads to the quantitative formation of aziridines in clean solid-to-solid reactions despite very large structural changes in the transition from reactant to product. Analysis of the reaction progress by powder X-ray diffraction, solid-state (13)C CPMAS NMR, solid-state FTIR spectroscopy, and thermal analysis has revealed that solid-to-solid reactions proceed either through metastable phases susceptible to amorphization or by mechanisms that involve a reconstructive phase transition that culminates in the formation of the stable phase of the product. While the key for a solid-to-solid transformation is that the reaction occurs below the eutectic temperature of the reactant and product two-component system, experimental evidence suggests that those reactions will undergo a reconstructive phase transition when they take place above the glass transition temperature.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
authors.forename: Denisse
authors.initials: D
authors.lastname: de Loera
authors.forename: Antoine
authors.initials: A
authors.lastname: Stopin
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Garcia-Garibay