Wavelength-dependent photochemistry of W(CO){sub 4}(en) (en = ethylenediamine): Evidence for distinct chemical reactivities from singlet and triplet ligand field excited states
- State Univ. of New York, Binghamton, NY (United States). Dept. of Chemistry
Studies of the photophysical and photochemical properties of organometallic compounds have now been extensively performed for over 25 years. In considering the photoreactivity of such complexes, it has usually been assumed that their singlet excited states are extremely short-lived and unreactive as a consequence of effective intersystem crossing mechanisms facilitated by the heavy metal and rapid internal conversions to the ground state. In this paper the authors report quantitative photochemical measurements obtained for W(CO){sub 4}(en) (en = ethylenediamine) following excitation into the lowest energy LF absorption manifold at several wavelengths. This system is of particular significance because, unlike most other substituted metal carbonyl complexes, its lowest lying LF absorption band is well removed from other electronic transitions and the lowest energy LF triplet absorption is a distinctive feature of the spectrum. Following excitation at various wavelengths, therefore, it is possible to populate the LF single and triplet energy levels exclusively and determine their quantitative photochemical reactivities directly. The results for W(CO){sub 4}(en) demonstrate conclusively that the LF excited states undergo separate photosubstitutional pathways and that reaction from the lowest lying LF triplet state takes place with a substantially reduced photoefficiency.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-89ER14039
- OSTI ID:
- 642371
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 7 Vol. 37; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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