@article {6692, title = {STEADY-STATE FLUORESCENCE EMISSION STUDIES ON POLYAZACYCLOPHANE MACROCYCLIC RECEPTORS AND ON THEIR ADDUCTS WITH HEXACYANOCOBALTATE(III)}, journal = {Journal of the Chemical Society-Dalton Transactions}, year = {1995}, note = {

ISI Document Delivery No.: QN860Times Cited: 29
Cited Reference Count: 27
Bernardo, ma parola, aj pina, f garciaespana, e marcelino, v luis, sv miravet, jf
Pina, Fernando/C-8161-2011; Parola, A. Jorge/F-4048-2010
Parola, A. Jorge/0000-0002-1333-9076
Royal soc chemistry
Cambridge

}, month = {1995}, pages = {993-997}, abstract = {

The steady-state fluorescence emission spectra of the azacyclophanes 2,5,8,11-tetraaza[12] paracyclophane (L(1)), 2,6,9,13-tetraaza[14]paracyclophane (L(2)), 14,15,17,18-tetramethyl-2,5,8,11-tetraaza-[12]paracyclophane (L(3)) and 16,17,19,20-tetramethyl-2,6,9,13-tetraaza[14]paracyclophane (L(4)) as a function of pH have been measured. The fully protonated species of each cyclophane gives the highest fluorescence-emission quantum yield. The shapes of the titration curves have been explained by the existence of an electron-transfer quenching effect from a non-protonated amine to the benzene chromophore. This effect is greater for macrocycles in which the first deprotonated amine group is closer to the benzene. The association constants for the interaction of the four fully protonated macrocycles with K-3[Co(CN)(6)] have been measured either by potentiometry or from fluorescence-emission measurements, and increase in the order L(3) approximate to L(4) \< L(1) approximate to L(2). The photoaquation quantum yields of K-3[Co(CN)(6)] have been measured in the presence of the macrocycles L(1) and L(2). and indicate that three of the CN nitrogens of the complex are involved in adduct formation with the fully protonated macrocycles, as supported by molecular modelling.

}, isbn = {0300-9246}, url = {://WOS:A1995QN86000014}, author = {Bernardo, M. A. and A. J. Parola and Pina, F and Garciaespana, E. and Marcelino, V. and Luis, SV and Miravet, J. F.} }