Transition metal-catalyzed C-N cross-coupling reaction of bromine-substituted pyranilidene derivatives: synthesis, characterization, and optical properties study of pyran-based chromophores

摘要

In this work, the C-N cross-coupling reaction between bromine-substituted pyranilidene derivatives, and a variety of secondary amines was studied in the presence of transition metal catalysts. The CuI/l-proline, Pd(OAC)(2)/PPh3, and MnCl2.6H(2)O/l-proline were chosen as catalyst/ligand systems. The copper-catalyzed Ullmann amination reaction in the presence ofl-proline as auxiliary ligand shows the best yield. The structure of pyran-based chromophores was confirmed using FT-IR,H-1 NMR,C-13 NMR, and mass spectroscopy. Additionally, the linear optical properties of final compounds were investigated using UV-Vis and fluorescent spectroscopy. The large stokes shifts for final compounds show the capability of using these compounds in optical applications.