Some new symmetric rigidified triheterocyclic heptamethinecyanine dyes absorbing in the near infrared
2002; Elsevier BV; Volume: 53; Issue: 2 Linguagem: Inglês
10.1016/s0143-7208(02)00003-7
ISSN1873-3743
AutoresSusana S. Ramos, Paulo F. Santos, Lucinda V. Reis, Paulo Almeida,
Tópico(s)Porphyrin and Phthalocyanine Chemistry
ResumoSeveral new rigidified heptamethinecyanine dyes bearing different N-alkyl chains were readily prepared by a novel semi-catalyzed method, envisioning their potential usefulness for photodynamic therapy. All dyes displayed absorption within the so-called “phototherapeutic window”. In order to improve the structural versatility of the dyes, it was incorporated in the exocyclic conjugated bridge present in the polimethine chain a chlorine atom. In some cases the later underwent an unexpected in situ substitution by a third oxygenated heterocyclic group, depending on the solubility of the chloro dye in the reaction solvent. Two possible mechanisms for the formation of these triheterocyclic dyes are proposed. The full spectroscopic characterisation of all the cyanines synthesised is described.
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