Intermolecularly hydrogen-bonded dimeric helices: tripyrrindiones

[摘要] A rare and unusual class of tripyrrolic compounds, violet-colored tripyrrin-1,14-diones, can be prepared easily and in moderately high yields from base (piperidine)-catalyzed condensation of 3-pyrrolin-2-ones with 2,5-diformylpyrroles. Dipyrrinones adopt the all-syn-Z conformation leading to helical, lock-washer like structures, which form dimers that are held together by intermolecular hydrogen bonds in nonpolar solvents and in the crystal. Strong bathochromic spectral shifts of the tripyrrindione similar to 480 nm long wavelength UV-visible absorption band are seen with added base: DBU, 615 nm; TFA, 573 nm; and Zn(OAc)(2), 586 nm. (c) 2007 Elsevier Ltd. All rights reserved.

[发布日期] 2007-11-05

[关键词] tripyrroles;hydrogen bonds;X-ray crystallography