Beiträge zur Chemie der Pyrrolpigmente, 73. Mitt.

摘要

Several 10-arylbilatrienes-abc substituted with various substituents in position “4” of the phenyl residue were prepared. Configurational and conformational analysis using NOE-measurements, UV-VIS spectra together withPPP-SCF-LCAO-MO-CI-calculations, ring current effects andpKa-determinations showed the bilin chromophor to adopt a more or less undisturbed (Z,Z,Z)-sp,sp,sp-geometry, compared to bilatrienes-abc. The plane of the aryl moiety is, however, heavily twisted against the mean plane of the bilin chromophor—the torsional angle is estimated to be abou