Quinolines by Three-Component Reaction: Synthesis and Photophysical Studies

Autor(es)

Sales, Eric S. ^[1] ; Schneider, Juliana M. F. M. ^[1] ; Santos, Marcos J. L. ^[1] ; Bortoluzzi, Adailton J. ^[2] ; Cardoso, Daniel R. ^[3] ; Santos, Willy G. ^[3] ; Merlo, Aloir A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Rio Grande do Sul, Inst Quim, BR-90040060 Porto Alegre, RS - Brazil

^[2] Univ Fed Santa Catarina, Dept Quim, BR-88040900 Florianopolis, SC - Brazil

^[3] Univ Sao Paulo, Chem Inst Sao Carlos, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 26, n. 3, p. 562-571, MAR 2015.
• Citações Web of Science: 7

Resumo

The synthesis of five quinolines 8-octyloxy-4-[4-(octyloxy)phenyl]quinoline and 6-alkoxy- 2-(4-alkoxyphenyl)-4-[(4-octyloxy)aryl]quinolines are described by three-component coupling reaction mediated by Lewis acid FeCl3 and Yb(OTf)3. 4-n-octyloxybenzaldehyde, anisaldehyde, 4-n-octyloxyaniline p-anisidine, and 1-ethynyl-4-heptyloxybenzene, 1-ethynyl-4-octyloxybenzene and 2-ethynyl-6-heptyloxynaphthalene are the reagents in this protocol. A Yb3+ catalyst resulted in higher yields of quinolines than Fe3+. Polarizing optical microscopy (POM) revealed that none of the quinolines were liquid crystals, even the more anisotropic. UV-Vis measurements of one of the quinolines in polar solvent show two absorption bands at 280 and 350 nm related to π,π* and n,π* transitions. No changes were observed to lower-energy absorption band (ε < 104 mol L-1 cm-1) related to n,π* transition. A laser flash photolysis study for one of the quinolines relates a main transient band at 450 nm with a lifetime of 2.6 µs in ethanol, which is completely quenched in the presence of oxygen. This transient band was assigned to triplet-triplet absorption of one of the quinolines, which is semi-oxidised in the presence of phenol. Radiative rate constants have been determined along singlet and triplet excited state energies (3.39 and 3.10 eV, respectively). The chemical structure of one of the quinolines was also unequivocally confirmed by single-crystal X-ray analysis. (AU)

• Processo FAPESP: 12/19823-4 - Fototransientes de organoboranos gerados por fotólise direta e sensitização por flavinas.
• Beneficiário: Willy Glen Santos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado