- Quinolines by three-component reaction: Synthesis and photophysical studies
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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 4 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.
- Sales, Eric S.,Schneider, Juliana M. F. M.,Santos, Marcos J. L.,Bortoluzzi, Adailton J.,Cardoso, Daniel R.,Santos, Willy G.,Merlo, Aloir A.
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p. 562 - 571
(2015/03/14)
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- THE EFFECT OF CHANGES IN HYDRODYNAMIC CONDITIONS ON THE RESPONSE OF CALCIUM-SELECTIVE MEMBRANE ELECTRODES WITH A MACROCYCLIC CARRIER
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Shifts of the potentials of a calcium ion-selective electrode based on the complex of 7,19-dibenzyl-2,2,3,3-tetramethyl-7,19-diaza-1,4,10,13,16-pentaoxacycloheneicosane-6,20-dione with calcium tetra(4-chlorophenyl)borate in various membrane solvents caused by changes in hydrodynamic conditions in the measured solution were examined.The use of 2-fluoro-2'-nitrodiphenyl ether as a membrane solvent combined with substitution of benzyl groups with octyl ones in the neutral carrier eliminates this unfavourable phenomenon while preseving the selectivity parameters of the elect rode.
- Ryba, Olen,Petranek, Jaromir
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p. 2371 - 2375
(2007/10/02)
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