N,N-dimethylamino-phenylene–acetylene scaffolding: Structure–property relationships

Dicyanobenzene and dicyanopyrazine derived X-shaped charge-transfer chromophores: comparative and structure–property relationship study

“…R f = 0.72 (SiO 2 ; CH 2 Cl 2 -hexane 6 : 1). 19,135.71,133.68,131.05,115.49,112.59,111.92,108.23,102.91,85.51,40.32. IR (HATR): ν max / cm −1 = 2920−1 = , 2177−1 = (CN), 1605−1 = , 1360−1 = , 1222−1 = , 1037 H 5.35,N 13.52;Found C 81.04,H 5.54,N 13.31.…”

“…IR (HATR): ν max / cm −1 = 3004, 2206−1 = 3004, (CN), 1608−1 = 3004, , 1525−1 = 3004, , 1356−1 = 3004, , 1222−1 = 3004, , 1130 H 4.92,N 9.11;Found C 85.50,H 5.01,N 9.21. Chromophore B7. General procedure for Sonogashira crosscoupling with 4″-ethynyl-N,N-dimethyl-[1,1′:4′,1″-terphenyl]-4amine 10,19 (250 mg) gave 198 mg (69%) of chromophore B7 as an orange solid. M.p.…”

“…In contrast to all N,N-dimethylamino-substituted π-linkers, which showed emission properties, 19 only less extended chromophores B1-B4 showed fluorescent behaviour (Table 4, the ESI Fig. S5 †).…”

“…N,N-Dimethylamino-substituted π-linkers with boronic acid (ester) function and terminal acetylene moiety were prepared from commercially available or known short π-linkers 18 and their extension/alternation by cross-coupling reactions with [(4-iodophenyl)ethynyl]trimethylsilane. 10,19 With the extended π-linkers and 4,5-diiodobenzene-1,2-dicarbonitrile 11 in hand, we have carried out twofold Suzuki-Miyaura cross-coupling reactions leading to target molecules B1, B3 and B4 in yields of 83, 87 and 79% (Scheme 1). These chromophores possess the π-linker connected directly to the dicyanobenzene moiety via a 1,4-phenylene unit.…”

Alphabet‐Inspired Design of (Hetero)Aromatic Push–Pull Chromophores

“…It was shown that heteroaromatic pyrazine acceptors imparted stronger ICT than aromatic benzene, as indicated by the narrowed HOMO–LUMO gap, bathochromically shifted longest‐wavelength absorption maxima, and higher quinoid character. However, further property tuning has been carried out through a systematic extension of the π‐system by various combinations of acetylenic and 1,4‐phenylene units,69 which revealed that, especially for the most extended molecules ( n =2), the optical nonlinearities of 37 / 38 were dictated not only by the electron‐withdrawing power of the DCB and DCP units, but gradually also by the length, composition, and planarity of the π‐system. Hence, the most extended chromophores 37 with the DCB unit showed higher second‐harmonic generation (SHG) responses than isolobal DCP chromophores 38 (e.g., 3.2/3.0 or 4.9/3.1 pm V −1 ) 68…”