Frederick R. Longo

Bio: Frederick R. Longo is an academic researcher from Drexel University. The author has contributed to research in topics: Porphin & Hydrolysis. The author has an hindex of 17, co-authored 37 publications receiving 5168 citations. Previous affiliations of Frederick R. Longo include United States Department of the Army.

A mechanistic study of the synthesis and spectral properties of meso-tetraarylporphyrins.

Abstract: W e have prepared 11 new derivatives of meso-tetraphenylporphin which are substituted on the phenyl groups. Kinetic studies of the rate of porphyrin formation and of oxygen consumption lead us to conclude that oxygen oxidation is the rate-determining step under ordinary synthetic conditions. W e have also determined the extinction coefficients and the relative fluorescence intensities of these compounds. n recent years we have been involved in a mechanistic I invest igat ion of the Rothemund reaction, which is the only high-yield synthesis k n o w n for porphyrins (1) Supported by the National Institutes of Health, General Medical (2) National Institutes of Health Fellow, 1970-1971. (3) (a) P. Rothemund, J . Amer. Chem. SOC., 57, 2010 (1936); (b) P. Rothemund, ibid., 61, 2912 (1939); (c) P. Rothemund and A. R . Sciences, Grant No. G M 15019. starting from simple precursors. Badger, Jones, and Laslett, who were the first to consider the mechanism, proposed that the reaction proceeded through the formation of an a,y-dihydroxyporphyrinogen (1) chiefly Menotti, ibid., 63, 267 (1941); (d) P. Rothemund and A. R. Menotti, ibid., 70, 1808 (1948). (4) G. M. Badger, R . A. Jones, and R. L. Laslett, Ausfr. J . Chem., 17, 1028 (1964). Journal of the American Chemical Society 1 94:11 I May 31, 1972

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

Abstract: Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

A colorimetric sensor array for odour visualization

Abstract: Array-based vapour-sensing devices are used to detect and differentiate between chemically diverse analytes. These systems--based on cross-responsive sensor elements--aim to mimic the mammalian olfactory system by producing composite responses unique to each odorant. Previous work has concentrated on a variety of non-specific chemical interactions to detect non-coordinating organic vapours. But the most odiferous, toxic compounds often bind readily to metal ions. Here we report a simple optical chemical sensing method that utilizes the colour change induced in an array of metalloporphyrin dyes upon ligand binding while minimizing the need for extensive signal transduction hardware. The chemoselective response of a library of immobilized vapour-sensing metalloporphyrin dyes permits the visual identification of a wide range of ligating (alcohols, amines, ethers, phosphines, phosphites, thioethers and thiols) and even weakly ligating (arenes, halocarbons and ketones) vapours. Water vapour does not affect the performance of the device, which shows a good linear response to single analytes, and interpretable responses to analyte mixtures. Unique colour fingerprints can be obtained at analyte concentrations below 2 parts per million, and responses to below 100 parts per billion have been observed. We expect that this type of sensing array will be of practical importance for general-purpose vapour dosimeters and analyte-specific detectors (for insecticides, drugs or neurotoxins, for example).