Synthesis and properties of N-substituted maleimides conjugated with 1,4-phenylene or 2,5-thienylene polymers

Color Tuning of the Aggregation-Induced Emission of Maleimide Dyes by Molecular Design and Morphology Control

Aggregation-induced emission (AIE)-active maleimide dyes, namely, 2-p-toluidino-N-p-tolylmaleimide, 3-phenyl-2-toluidino-N-p-tolylmaleimide, 2-p-thiocresyl-3-p-toluidino-N-p-tolylmaleimide, and 2,3-dithiocresyl-N-arylmaleimides, were synthesized by facile synthetic procedures. The dyes show intense emission in the solid state, and emission colors were controlled from green (λmax =527 nm) to orange (λmax =609 nm) by varying the substituents at the 2- and 3-positions of the maleimide and the packing structures in the solid state. 2,3-Disubstituted maleimide dyes effectively underwent redshifts of their emission wavelength. Furthermore, some of the dyes exhibited mechanochromism and polymorphism, and their emission properties were dramatically dependent on the morphology of the solid samples. The mechanisms of the emission behaviors were investigated by X-ray diffraction. The substituent of the nitrogen atom of the maleimide ring affected the intermolecular interactions and short contacts, which were observed by single crystal X-ray crystallography, to result in completely different emission properties.

Effect of alkyl groups on emission properties of aggregation induced emission active N-alkyl arylaminomaleimide dyes

Aggregation induced emission (AIE) active N-alkyl aminomaleimide dyes with various kinds of N-alkyl groups were synthesized in a one pot process.

3,4-Bis(4-bromophenyl)-N-phenylmaleimide

In the title mol­ecule, C₂₂H₁₃Br₂NO₂, the three benzene rings are arranged in a propeller-like fashion around the central malemide ring, making dihedral angles of 48.2 (4), 30.2 (4) and 34.8 (4)° with the malemide ring. The C—C single-bond lengths connecting benzene groups and maleimide are significantly shorter [C—C = 1.468 (9) and 1.478 (9) Å] than a typical Csp³—Csp³ single bond, indicating partial conjugation between the benzene and the mal­eimide. A weak non­classical C—H⋯O hydrogen bond helps to stabilize the crystal structure.