Low-symmetry phenyl substituted pyrazine analogues of subphthalocyanine type dyes

First Subphthalocyanine Analogue with Fused 6H‐1,4‐diazepine Ring and its Conversion to Aminobenzamide Derivative

“…Due to high reactivity of TFPN in cyclotrimerization reaction and its ability to involve in the reaction other less reactive dinitriles, it is often used in the synthesis of various low-symmetry subporphyrazines. [24][25][26][27][28] In our case, mixed co-cyclotrimerization of Ph 2 Dz(CN) 2 and TFPN in the presence of BCl 3 gave three subporphyrazine-type products (overall yield 10-12%) which after separation by column chromatography can be easily distinguished by UV-VIS spectra (Figure 2). Elution with CHCl 3 on a silica column affords two fast moving fractions which can be completely separated using CH 2 Cl 2 :hexane mixture (3:1) (R f =0.78 and 0.43) and very slow 3 rd fraction (R f =0.37 in CHCl 3 ).…”

“…Taking into account an electron‐donor nature of the 1,4‐diazepine ring present in the dinitrile (Ph 2 Dz(CN) 2 ) (A), we have chosen 3,4,5,6‐tetrafluorophthalonitrile (TFPN) as an electron‐accepting partner (B) in co‐cyclotrimerization. Due to high reactivity of TFPN in cyclotrimerization reaction and its ability to involve in the reaction other less reactive dinitriles, it is often used in the synthesis of various low‐symmetry subporphyrazines [24–28] …”

“…The most widely used precursor for mixed cyclotrimerization is commercially available 3,4,5,6‐tetrafluorophthalonitrile [10] . Among low‐symmetry [ s Pc] analogues, macrocycles containing, along with one or two perfluorinated benzene rings, fused naphthalene, [10,23] pyrene, [24] 1,2,5‐thiadiazole or 1,2,5‐selenadiazole [25,26] and pyrazine [27,28] fragments were described. It is noteworthy that unsymmetrical subphthalocyanines bearing perfluorinated and unsubstituted benzene or naphthalene subunits were studied as probes for visualizing fluorescence for MDA‐MB‐231 or Hela cells [29,30] …”

Synthesis, Optical Properties, and Fluorescence Cell Imaging of Novel Mixed Fluorinated Subphthalocyanines

“…For the low-symmetry 5 – 7 , the maximum of the Soret band observed in the UV region at 294–303 nm was slightly shifted bathochromically compared with the symmetrical 4 (307 nm). TDDFT calculation (see Tables S3–S5 ) indicated that this intense absorption in the UV region, similar to that of low-symmetry F 8 Ph 2 N 2 sPc and F 4 Ph 4 N 4 sPc [ 28 ], arose from the overlap of several complex excited states. Compared with 4 , the substitution of the peripheral fluorine atoms with the different groups had a small effect on the Q-band position and more of an effect on the Q-band shape and the fluorescence quantum yield.…”

“…The methods mentioned above are mainly applied to the synthesis of the SubPcs with three peripheral isoindole rings linked to the same group. Mixing multiple phthalonitrile derivatives by a usual condensation reaction in a one-pot method has always been used to produce a low-symmetry mixture SubPcs and yields a series of A 3 -, A 2 B-, AB 2 -, and B 3 -type SubPcs, where “A” and “B” are different peripheral moieties of SubPc, such as pyrene-fused SubPcs [ 26 ], fluorinated SubPcs [ 27 ], pyrazine-fused SubPcs [ 28 ], and fluorenone-fused SubPc [ 29 ]. Our group previously reported a related work that showed that fluorinated S 2 CO-fused SubPcs [ 30 ] were produced from a mixed reaction of different phthalonitrile precursors.…”