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A Study in Mauve: Unveiling Perkin's Dye in Historic Samples
Sousa, Micaela M.; Melo, Maria J.; Parola, A. Jorge; Morris, Peter J. T.; Rzepa, Henry S.; Melo, J. Sérgio Seixas deThe analysis of different historic mauve samples - mauve salts and dyed textiles - was undertaken to establish the exact nature of the iconic dye produced by W. H. Perkin in the nineteenth century. Fourteen samples from important museum collections were analyzed, and it was determined that, in contrast to the general wisdom that mauveine consists of C26 and C27 structures, Perkin's mauveine is a complex mixture...
A Study in Mauve: Unveiling Perkin's Dye in Historic Samples
Sousa, Micaela M.; Melo, Maria J.; Parola, A. Jorge; Morris, Peter J. T.; Rzepa, Henry S.; Melo, J. Sérgio Seixas deThe analysis of different historic mauve samples - mauve salts and dyed textiles - was undertaken to establish the exact nature of the iconic dye produced by W. H. Perkin in the nineteenth century. Fourteen samples from important museum collections were analyzed, and it was determined that, in contrast to the general wisdom that mauveine consists of C26 and C27 structures, Perkin's mauveine is a complex mixture...
Synthesis and photophysical properties of dansyl-based polyamine ligands and th...
Parola, A. Jorge; Lima, João Carlos; Pina, Fernando; Pina, João; Melo, João Seixas de; Soriano, Conxa; García-España, Enrique; Aucejo, RicardoThe synthesis, potentiometric studies and photophysical properties of two new polyamine ligands (L1 and L2) possessing the dansyl chromophore were studied in aqueous 0.15 M NaCl. The compounds show the absorption and emissions bands characteristic of the dansylamide fluorophore and both present intramolecular excited state proton transfer at intermediate pH ranges. One of the ligands (L2) strongly coordinates Z...
Identification of 7,4prime-Dihydroxy-5-methoxyflavylium in ldquoDragon's Bloodr...
Melo, Maria J.; Sousa, Micaela; Parola, A. Jorge; Melo, J. Sérgio Seixas de; Catarino, Fernando; Marçalo, Joaquim; Pina, FernandoThe compound 7,4prime-dihydroxy-5-methoxyflavylium (dracoflavylium) was identified as the major red colorant in samples of the resin ldquodragon's bloodrdquo, extracted from the tree Dracaena draco. The complex network of reversible chemical reactions that dracoflavylium undergoes in aqueous solution is fully described; for the first time, all the equilibrium constants that enable a complete characterisation of...
Identification of 7,4prime-Dihydroxy-5-methoxyflavylium in ldquoDragon's Bloodr...
Melo, Maria J.; Sousa, Micaela; Parola, A. Jorge; Melo, J. Sérgio Seixas de; Catarino, Fernando; Marçalo, Joaquim; Pina, FernandoThe compound 7,4prime-dihydroxy-5-methoxyflavylium (dracoflavylium) was identified as the major red colorant in samples of the resin ldquodragon's bloodrdquo, extracted from the tree Dracaena draco. The complex network of reversible chemical reactions that dracoflavylium undergoes in aqueous solution is fully described; for the first time, all the equilibrium constants that enable a complete characterisation of...
Spectroscopy and Coordination Chemistry of a New Bisnaphthalene−Bisphenanthroli...
Pina, João; Melo, J. Seixas de; Pina, Fernando; Lodeiro, Carlos; Lima, J. C.; Parola, A. Jorge; Soriano, Conxa; Paz Clares, M.; Albelda, M. TeresaA new fluorescent macrocyclic structure (L1) bearing two naphthalene units at both ends of a cyclic polyaminic chain containing two phenanthroline units was investigated with potentiometric and fluorescence (steady-state and time-resolved) techniques. The fluorescence emission spectra show the simultaneous presence of three bands: a short wavelength emission band (naphthalene monomer), a middle emission band (...
Synthesis and H+, Cu2+, and Zn2+ Coordination Behavior of a Bis(fluorophoric) B...
Clares, M. Paz; Aguilar, Juan; Aucejo, Ricardo; Lodeiro, Carlos; Albelda, M. Teresa; Pina, Fernando; Lima, J. C.; Parola, A. Jorge; Pina, JoãoThe synthesis, protonation behavior, and Cu2+ and Zn2+ coordination chemistry of the novel bibrachial aza lariat ether (naphthalen-1-ylmethyl)[2-(20-2-[(naphthalen-1-ylmethyl)amino]ethyl-3,6,9,17,20,23,29,30-octaazatricyclo[23.3.1.1*11,15*]triaconta-1(29),11(30),12,14,25,27-hexaen-6-yl)ethyl]amine (L) are discussed. The macrocycle, which has two aminoethyl naphthyl moieties symmetrically appended to a 2:2 azapy...
Intramolecular Excimer Formation in a Tripodal Polyamine Receptor Containing Th...
Albelda, M. Teresa; García-España, Enrique; Gil, Laura; Lima, João C.; Lodeiro, Carlos; Melo, J. Seixas de; Melo, M. João; Parola, A. JorgeA comprehensive investigation on the energetics and dynamics of a new fluorescent sensor constituted by a tripodal polyamine receptor containing three naphthalene fluorophores, compound L, is reported. The influence of external factors such as the solvent, hydrogen ion concentration, and temperature in the photophysics of the sensor is discussed. The temperature dependence of monomer/excimer interconversion of ...
Exploring the Photocatalytic Properties and the Long-Lifetime Chemosensor Abili...
Lodeiro, Carlos; Pina, Fernando; Parola, A. Jorge; Bencini, Andrea; Bianchi, Antonio; Bazzicalupi, Carla; Ciattini, Samuele; Giorgi, ClaudiaIn this work a new water-soluble long-lifetime chemosensor, containing a polyamine unit connected to a complexed Ru(II) metal center, is described. Its crystal structure has been characterized by X-ray analysis. The polyamine macrocyclic unit is capable of anchoring cationic or anionic substrates, according to its protonation state. Examples of electron transfer involving the ruthenium complex core and the boun...
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