Determining the Quantum Efficiency for Activation of an Organometallic Photointiator for Cationic Polymerization

摘要

We wish to present a new experiment in mechanistic organometallic photochemistry that can be used in either the physical, inorganic, or advanced unified laboratory. This experiment involves measuring the photochemical efficiency (quantum yield) for arene displacement from a mixed-sandwich compound of iron, [(η5-C5H5)Fe(η6-isopropyl-benzene)](PFg) (Scheme I). Arene displacement is the dominant photochemical reaction of mixed Cp-M-arene complexes in polar organic solvents when M = Fe, Ru, and Os. If M = Fe, then II (Scheme I) is unstable at room temperature and will react further to form CpaFe, Fe2+, and arene. Moreover, if suitable ligands, L, are present, then II will react to form stable complexes of the type CpML3+.