3 documents found, page 1 of 1
A 1000-year-old mystery solved: Unlocking the molecular structure for the medie...
Nabais, P.; Oliveira, J.; Pina, F.; Teixeira, N.; de Freitas, V.; Brás, N. F.; Clemente, A.; Rangel, M.; Silva, A. M. S.; Melo, M. J.The molecular structure of the medieval watercolor known as folium has finally been solved in the 21st century. The interdisciplinary approach taken was the key to producing extracts that had been prepared following medieval instructions, and shows the blue/purple chromophore as the major dye in Chrozophora tinctoria fruits (shell). A multi-analytical characterization of its structure was made using HPLC-DAD-MS...
Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular ...
Melo, J. Seixas de; Rondão, R.; Burrows, H. D.; Melo, M. J.; Navaratnam, S.; Edge, R.; Voss, G.Spectral and photophysical properties of the indigo derivative Cibalackrot in keto and reduced (leuco) forms were studied by absorption spectra, fluorescence and pulse radiolysis and compared with the structurally similar indigo. With the keto form of this dye, fluorescence (phiF = 0.76) and intersystem crossing (phiT = 0.11) are dominant, whereas with indigo, efficient internal conversion (phiIC = 0.99) is obs...
Photophysical and Spectroscopic Studies of Indigo Derivatives in Their Keto and...
Melo, J. Seixas de; Moura, A. P.; Melo, M. J.A comprehensive spectroscopic and photophysical study of the keto and leuco forms of indigo and three other ring-substituted derivatives in solution was performed. The characterization involves absorption, fluorescence, and triplet−triplet absorption spectra, making it possible to obtain the quantum yields for fluorescence (phiF), singlet−triplet intersystem crossing (phiISC), internal conversion (phiIC), and l...