A method has been developed that enables resonance Raman spectra of photolabile species in solution to be recorded under conditions where the level of photoalteration is controlled: a low level enables reactant spectra to be recorded, whereas a high level enables the spectra of short-lived transient species to be recorded in real time using continuous-wave (CW) lasers and standard Raman detection equipment. The design includes a sealed flow system, enabling air-sensitive species to be studied under an inert atmosphere. A simple theoretical model has been developed to aid the interpretation of experimental results, and its applicability is demonstrated. Controlled photoalteration and its theory are demonstrated with 413.1-nm excitation of carbonmonoxymyoglobin (MbCO), which generates deoxymyoglobin (deoxy-Mb) on photolysis, and for which the spectra of both species are well established. The methods have also been applied to two air-sensitive, photolabile transition metal carbonyls using 514.5-nm wavelength excitation: for Cp<sub>2</sub>Mo<sub>2</sub>(CO)<sub>6</sub> (Cp = η<sup>5</sup>–C<sub>5</sub>H<sub>5</sub>), increasing levels of photoalteration result only in a decrease in the parent band intensities, relative to the solvent bands; for Cp<sub>2</sub>Fe<sub>2</sub>(CO)<sub>4</sub> , increasing levels of photoalteration result in the appearance of additional bands that are assigned to the transient species CpFe(μ–CO)<sub>3</sub>FeCp, formed following the loss of a CO ligand.

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access OSA Member Subscription