Cascading Effect of Large Molecular Motion in Crystals: A Topotactic Polymorphic Transition Paves the Way to Topochemical Polymerization.
J Am Chem Soc
; 145(17): 9607-9616, 2023 May 03.
Article
en En
| MEDLINE
| ID: mdl-37078975
A topochemical polymerization governed by a topotactic polymorphic transition is reported. A monomer functionalized with azide and an internal alkyne crystallized as an unreactive polymorph with two molecules in the asymmetric unit. The molecules are aligned in a head-to-head fashion, thereby avoiding the azide-alkyne proximity for the topochemical azide-alkyne cycloaddition (TAAC) reaction. However, upon heating, one of the two conformers underwent a drastic 180° rotation, leading to a single-crystal-to-single-crystal (SCSC) polymorphic transition to a reactive form, wherein the molecules are head-to-tail arranged, ensuring azide-alkyne proximity. The new polymorph underwent TAAC reaction to form a trisubstituted 1,2,3-triazole-linked polymer. These results, showing unexpected topochemical reactivity of a crystal due to the intermediacy of an SCSC polymorphic transition from an unreactive form to a reactive form, highlight that predicting topochemical reactivity by relying on the static crystal structure can be misleading.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Am Chem Soc
Año:
2023
Tipo del documento:
Article
País de afiliación:
India
Pais de publicación:
Estados Unidos