A new series of push-pull arylvinyldiazines has been efficiently prepared by aldol condensation between the appropriate methyldiazine and aromatic aldehyde. The optical absorption and emission properties of these chromophores were studied in different solvents and media. These compounds act as polarity sensors with a strong positive emission solvatochromism. This behavior suggests a highly polar emitting state, which is characteristic of compounds that undergo an internal charge transfer upon excitation. These molecules also exhibit halochromic properties and are potential colorimetric and luminescence pH sensors. The second-order nonlinear properties have been investigated for some of the compounds, and large and positive mu beta are obtained, in particular, for pyrimidine derivatives.
Ruthenium(II)-Catalyzed C–H (Hetero)Arylation of Alkenylic 1,<i>n</i>-Diazines (<i>n</i> = 2, 3, and 4): Scope, Mechanism, and Application in Tandem Hydrogenations
C–H bond arylation. Mixtures of E:Z isomeric products were observed in some cases, which were further hydrogenated in a tandem manner in the presence of the remaining rutheniumcatalyst from the first step, representing an alternative approach to more difficult C(sp3)–H bond functionalization. According to mechanistic studies, the unexpected E:Z product formation seems to occur by thermal C═C bond isomerization