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ERIC Number: EJ820777
Record Type: Journal
Publication Date: 2007-Sep
Pages: 3
Abstractor: As Provided
Reference Count: 24
ISBN: N/A
ISSN: ISSN-0021-9584
Determining the Quantum Efficiency for Activation of an Organometallic Photoinitiator for Cationic Polymerization: An Experiment for the Physical or Inorganic Chemistry Laboratory
Hayes, David M.; Mahar, Maura; Schnabel, R. Chris; Shah, Paras; Lees, Alistair J.; Jakubek, Vladimir
Journal of Chemical Education, v84 n9 p1483-1485 Sep 2007
We present a new laboratory experiment on the photochemistry of organometallic [eta][superscript 5],[eta][superscript 6]-mixed-sandwich compounds, which is suitable for both the physical chemistry and inorganic chemistry laboratory. Specifically, students use 1,10-phenanthroline to trap the intermediate formed when [CpFe(isopropylbenzene)]PF[subscript 6] is photolyzed with 458 nm light from an argon-krypton laser. Using quantitative UV-vis spectroscopy students then determine the quantum yield of arene ring displacement from the mixed-sandwich complex. The photogenerated intermediate, [CpFe(solvent)[subscript 3]][superscript +] is an efficient initiator for the polymerization of epoxides, dicyanate esters, pyrrole, styrene, dioxolenes, and acrylates. The efficiency with which the intermediate is photochemically formed is therefore an important property in determining its commercial utility. Although the experiment can easily be done in one 3-4 hour laboratory period, it readily lends itself to broadening into a multi-week research project. In this mode, students can examine how changing the nature of the solvent and the irradiation wavelength affect the quantum yield of reaction. Such information can be used to reveal the role of the solvent in the reaction and the electronic excited states from which reaction occurs. Furthermore, in the inorganic laboratory, students could be asked to synthesize [CpFe(isopropylbenzene]PF[subscript 6] before looking at its photochemical behavior, thus gaining experience in working under air-free conditions. (Contains 1 scheme, 2 figures and 1 table.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail: jchemed@egpp.com; Web site: http://www.jce.divched.org
Publication Type: Journal Articles; Reports - Evaluative
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A