Pentafluorosulfanyl (SF5) in dyes: C3-Regioselective synthesis of α-mono-substituted subphthalocyanine with SF5-phenyl group

•Subphthalocyanine having Ph(SF5)2 group on α-position was synthesized.•The effect of SF5 on subphthalocyanine was investigated by comparison with CF3.•The SF5 moiety enables regioselective synthesis, while CF3 cannot.•Bulky SF5 group controls dihedral angle of the phenyl plane of subphthalocyanine.

Pentafluorosulfanyl (SF5) is a unique fluorinated functional group. It has high lipophilicity and electronegativity, and is chemically and thermally stable. In addition, the steric hindrance of SF5 is larger than that of the trifluoromethyl (CF3) group. Therefore the introduction of SF5 group into functional dyes such as phthalocyanines and subphthalocyanines should be an attractive strategy to improve their robustness and alter their optical property. We attempted the C3-regioselective cyclotrimerization of aryl-substituted phthalonitriles 3 to provide subphthalocyanines (SubPcs) 1. α-Mono-substituted SubPc 1a was C3-regioselectively synthesized by introducing a bis(SF5)Ph group on the α-peripheral position providing 1a as a single isomer. The effect of the SF5 group on the synthesis and optical property of SubPcs were investigated by comparing with the H and CF3 analogues, 1b and 1c.

Graphical abstractThe pentafluorosulfanyl (SF5) group is one of the most attractive, but unexploited fluorinated functional groups. We disclose the regioselective synthesis of α-mono-substituted subphthalocyanine with bis(SF5)Ph on the α-position. The effect of the SF5 moiety was investigated by comparison with CF3 and H analogues.Figure optionsDownload full-size imageDownload as PowerPoint slide