Michael R. McDonald

Synthesis, reactivity and spectroscopy of ferrocene-functionalised porphyrins, with a conjugated connection between the ferrocene and the porphyrin core

Several new ferrocene-functionalised porphyrins and a ruthenocene-functionalised porphyrin have been synthesized and studied using electrochemistry, electronic absorbance and resonance Raman spectroelectrochemical techniques. The porphyrin and ferrocene are observed to have limited effect on each other with the properties of the porphyrin dominating the spectroscopy of these molecules.

Pulsed-Accelerated-Flow Spectrometer with Position-Resolved Observation

The title instrument (PAF-PRO) permits the progress of rapid reactions to be monitored at 128 positions along a 2 cm observation cell as reactants flow down the cell. A decelerated push is used to give velocity changes from 21 to 2 m s(-1) during a time interval of 384 ms. Variation of flow velocity allows reaction rate constants to be resolved from the physical mixing process. The flow system brings the reacting solutions together in a 10-jet radial mixer 0.32 cm before the mixture enters the observation tube (0.203 cm width, 1.945 cm length). A masked charge-coupled device (CCD) is the array detector used to obtain transmittance data as a function of position and velocity. The masked portion of the CCD serves as a dynamic memory buffer for fast data acquisition. Pseudo-first-order rate constants are measured from 200 to 12 000 s(-1). The instrument also is calibrated for second-order reactions (equal concentrations) with initial half-lives of 0.3-1.5 ms. Applications of the PAF-PRO system for the study of fast multistep reactions are presented.