Star‐Shaped Compounds Having 1,3,5‐Triazine Cores

Abstract

The 1,3,5-triazine derivatives 1−4 having styryl or higher oligo(phenylenevinylene) chains in the 2-, 4-, and 6-positions represent star-shaped push-pull compounds. Alkoxy or dimethylamino groups on the peripheral benzene rings, which act as electron donors, and the central 1,3,5-triazine ring, which acts as an electron acceptor, cause intramolecular charge transfer (ICT) to occur in the absorption S 0 ǞS 1 . Protonation of the 1,3,5-triazine core enhances the effect, as demonstrated by a bathochromic shift; a secondary protonation on the dimethylamino groups, however, leads to the

Star‐Shaped Push‐Pull Compounds Having 1,3,5‐Triazine Cores

“…The detection limit in 1 H and 13 C NMR spectroscopy amounts to about 3 %. The three "homologous" aldehydes 2, 5 and 7 are then condensed in an alkaline medium with 2,4,6-trimethyl-1,3,5-triazine (8). The yield is high for the smallest system 9, moderate for 10 with longer side chains, and poor for 11, which has the longest side chains.…”

“…2,4,6-Tris[(E)-styryl]-1,3,5-triazine has a λ max value in the UV at 327 nm. [8] However, the intramolecular charge transfer (ICT) depends strongly on the distance of donor D and acceptor A. The transition energy ∆E (S 0 Ǟ S 1 ) of pushpull oligomers is lowered by the extension of the conjugation and by the ICT.…”

“…This result is in contrast to the analogous star-shaped oligomers with a 1,3,5-triazine core and three OPV arms with terminal alkoxy groups which belong to category a). [8] Alkoxy groups are weaker electron donors than dialkylamino groups; therefore the extension of the chromophores (increasing numbers n) can overcompensate the decrease of the ICT.…”

“…Some time ago we reported on the preparation and the properties of 2,4,6-tristyryl-1,3,5-triazines and their higher homologues having oligo (1,4-phenylenevinylene) [OPV] chains. [8][9][10] We are studying now star-shaped systems with a 1,3,5-triazine core and three OPV chains which bear ter-minal dialkylamino groups. This structure concept conveys the compounds an octupolar character with a strong pushpull effect in each of the three arms.…”

Konjugierte Oligomere mit terminaler Donor‐Acceptor‐Substitution

“…Bei weiterer Zugabe von CF 3 COOH werden auch die terminalen Aminogruppen protoniert, und die Lösung entfärbt sich (l max = 365 nm). [102] Die primäre Rotverschiebung geht auf eine Verstärkung des Push-pull-Effekts zurück. Sobald aber die Aminofunktionen auch protoniert werden, geht ihr Donor-Charakter verloren, und man hat ein A-(p-A) 3 [103] Von den in Schema 23 aufgeführten zentralen Donoren ist wohl das Benzolsystem am interessantesten; bisher sind damit allerdings nur wenige Vertreter, z.…”