Andreia S.F. Farinha

Synthesis of hexaphyrins and N-fused pentaphyrins bearing pyridin-4-ylsulfanyl groups

In recent years much attention has been devoted to expanded macrocyclic chemistry. Nevertheless, while several advancements were achieved in the synthesis of novel expanded porphyrin architectures, not much has been developed in the functionalization of these macrocycles. This report shows the selective replacement of the p-fluorine atoms of meso-pentakis(pentafluorophenyl) N-fused [22]pentaphyrin and meso-hexakis(pentafluorophenyl) [26]hexaphyrin with 4-mercaptopyridine moieties, thus increasing their potential as ligands for coordination chemistry and catalysis or electronic transfer applications striving new synthetic methodologies and a new set of specific applications for this type of compounds.

Analysing sulphate and chloride in mineral drinking water by flow injection analysis with a single acoustic wave sensor

Sulphate is a very hydrophilic anion, and, therefore, difficult to be selectively determined in aqueous solution with a coated sensor. Zinc(II) 2,3,9,10,16,17,23,24-Octatosylaminophthalocyanine was used for the first time as a sensitive coating. Selectivity to sulphate regarding chloride was not enough to ignore its contribution in mineral waters, and, therefore, an analytical protocol was carefully designed to allow the determination of both anions with this sensor. Results displayed on the label of eight commercial bottles of mineral waters are within the confidence interval of the values obtained with the FIA-sensor system, both for chloride and sulphate. However, results for chloride obtained by titrimetry are, in half of the cases, statistically different from the ones obtained by the sensor, and in 7 out of 8 of them more precise. There is an evidence of a systematic error in the chloride titrimetric analysis, consistent with a small overtaking of the equivalence point. Precision of the results obtained by the titrimetric analysis of sulphate were in 6 out of 8 of the analysis less precise than with the sensor, probably due to losses of the barium sulphate precipitate, which is consistent with the occurrence of lower values.