Stepwise formation of 1,3-diazolium-4-thiolates by münchnone cycloadditions: promising candidates for nonlinear optics.
An improved preparation of mesoionic heterocycles 1,3-diazolium-4-thiolates by [3 + 2] cycloadditions of münchnones with aryl isothiocyanates is reported. The process takes place with high or complete regioselectivity, and fast and clean transformations are observed under microwave heating in DMF. DFT calculations support that this cycloaddition proceeds preferably through a stepwise mechanism. Given the pattern substitution around the mesoionic ring resulting in a push-pull system, theoretical estimations predict large hyperpolarizabilities in some cases, which is typical of molecules exhibiting nonlinear optical responses.
Departamento de Química Orgánica e Inorgánica, QUOREX Research Group, Facultad de Ciencias, Universidad de Extremadura , E-06006, Badajoz, Spain.
David
D
Cantillo
Martín
M
Ávalos
Reyes
R
Babiano
Pedro
P
Cintas
José L
JL
Jiménez
Mark E
ME
Light
Juan C
JC
Palacios
Rocío
R
Porro