A Comparative Study of the Electronic Property of a Series of 2,4,6-Tri(5-Aryl-2-Thienyl)-1,3,5-Triazines Controlled by the Electronic Nature of Aryl Groups

An overview on synthetic strategies for the construction of star-shaped molecules

“…On the other hand, 2,4,6-tri(5-aryl-thiophen-2-yl)-1,3,5-triazines 302b-f were synthesized via Suzuki-Miyaura cross-coupling reactions of 2,4,6-tri(5-bromo-2-thienyl)-1,3,5triazine 303 with arylboronic acids 304 or tetramethyl-2-aryl-1,3,2-dioxaborolane 305 in the presence of cesium carbonate and Pd catalyst (Scheme 80). 6 The effect of tuning the electronic nature of aryl groups connected to thiophene peripheral of SSMs 302 was found to be consistent with the electronaccepting or electron-attracting capabilities of these molecules as deduced from their UV absorption and uorescence emission spectra. Moreover, compound 302e having Bu 2 N-group showed both absorption and emission solvatochromism (due to internal charge transfer), as well as colorimetric and luminescence proton-sensing properties in view of the visually observed changes in the color of the solution and emission related to the two-step protonation of the Bu 2 N-groups and the nitrogen atoms on the 1,3,5-triazine moiety.…”

“…2,4,6-Tri(thiophen-2-yl)-1,3,5-triazine 299 was synthesized in 80% yield by the reaction of 2-tributylstannylthiophene 7 with cyanuric chloride 293 in the presence of Pd(PPh 3 ) 4 (Scheme 79). 6,123 A selective lithiation of 299 and subsequent stannylation gave 2,4,6-tris(5-tributylstannyl-2-thienyl)-1,3,5-triazine 300. The latter compound underwent Stille coupling reaction with pentauorophenylbromide 301 in the presence of Pd(PPh 3 ) 4 to give 2,4,6-tris(5-pentauorophenyl-2-thienyl)-1,3,5-triazine 302a in 28% yield.…”

Star‐Shaped Conjugated Molecules with Oxa‐ or Thiadiazole Bithiophene Side Arms

“…[8,9] Star-shaped molecules with heterocyclic cores such as triazine are also reported. [1,11,12] Largerc ores containing heterocycles are frequently built from fused aromatic and heterocyclic rings such as benzodithiophene, [13] benzotrithiophene, [14][15][16] or phenylquinoxaline. [17] Starshaped compounds with triphenylamine-type cores, inducing non-planarity of the molecule,w ere also synthesized.…”

“…[18][19][20][21][22][23][24][25] It should be mentioned that the triazine core can play the role of an electron accepting unit to which arms with electro-donating groups are attached, whereas, inversely,a rms containing electro-accepting units can be attached to an electro-donating core. [20,22] Star-shaped molecules with thienylene (or thienyl)g roups frequently show interesting optical properties including photoluminescence of highq uantum yield, [19] solvatochromism, [12] and electrochromism. [26] They are electrochemically active [1,7,11] and can form a3 Dn etwork through electrochemical polymerization.…”

“…Benzene is probably the most popular aromatic core, however, more extended cores should also be mentioned such as truxene . Star‐shaped molecules with heterocyclic cores such as triazine are also reported . Larger cores containing heterocycles are frequently built from fused aromatic and heterocyclic rings such as benzodithiophene, benzotrithiophene, or phenylquinoxaline .…”