No abstract

Resonance Raman spectra of iron(1I) protoporphyrin IX [ Fe(II)PP] in dimethyl sulfoxide (DMSO) and deuterated DMSO were obtained at high and low photon densities using 10 ns laser pulses. At low photon density, comparison of the Raman spectra of the complex with those of carbonmonoxy-hemoglobin indicates that a lowspin, six-coordinate (DMSO),Fe(lI)PP complex exists; at high photon density, spectral comparisons with deoxyhemoglobin and the 2-methylimidazole heme complex (2-Melm)Fe(II)PP indicate that a transient high-spin, five-coordinate complex is formed by photodissociation of a DMSO ligand. This phenomenon is reversible and observable on a 10 ns time-scale.

No abstract

Because of the rapidly changing nature of chemical instrumentation, students must be trained in how to learn and understand new instruments. Toward this end, students are asked to create small instrument manuals, or instrument profiles, for the major pieces of equipment studied during an instrumental analysis course. This writing-intensive process of creating instrument profiles requires that students understand the basics of each type of instrument and that they are able to compare the instrument to other instruments. With the use of block and schematic diagrams, the major components within an instrument are emphasized such that students can discover subtle differences between types of instruments. Students’ ability to teach themselves new instruments is demonstrated at the end of the semester by creating an instrument profile for an instrument not specifically discussed during the course and by giving a short oral presentation to the class, providing everyone with brief exposure to many more technologies.

A demonstration of the degradation of food coloring dyes by oxidation via the Fenton reaction can be substituted with a simpler demonstration using the oxidant oxone with iron­(II) ions as an activator. The addition of small amounts of solid oxone and iron­(II) sulfate to solutions containing mixtures of food coloring results in successive degradation of food dyes within minutes, also showing a kinetic separation of color. Because food dyes of different colors degrade at different rates, successive changes in color during degradation can be observed for various dye mixtures. Catalyst-like behavior is also demonstrated; in the absence of a transition metal such as iron to activate the oxone, negligible color degradation is observed within the time frame of the demonstration. The demonstration presents an opportunity to introduce topics such as structural characteristics of organic chromophores, the catalyst-like behavior of a transition metal, the practical importance of chemical kinetics, and challenges involved in finding eco-friendly methods of efficiently oxidizing pollutants, including not only waste dyes but also personal care products and excreted pharmaceuticals.