Synthesis and Spectroscopic Properties of Diarylethene‐Subporphyrinoid Hybrids

Two novel diarylethene‐fused subporphyrinoids were prepared and characterized. A mono diarylethene derivative was obtained via a statistical condensation reaction with 2 eq. of 1,2‐dicyanobenzene and 1 eq. of thiophene‐disubstituted butenedinitrile. The symmetric triply diarylethene‐fused subporphyrazine was synthesized via a cyclotrimerization reaction of the thiophene‐disubstituted butenedinitrile derivative. These compounds were characterized by NMR spectroscopy and high‐resolution mass spectrometry. The spectroscopic properties have been measured in hexane and in chloroform. The mono diarylethene‐fused‐type compound showed photochromism at 580 nm and >700 nm wavelength, accompanied by degradation. According to DFT calculations, photoreactivity likely depends on the contribution of aromatic feature of pyrrole ring bonded to two thiophene rings.