title: Cryophotolysis of a caged oxygen compound for use in low temperature biological studies.
abstract: Mechanistic investigations of biological enzymatic processes require controlled initiation and monitoring of catalytic reactions. A well-known technique to trap and observe reaction intermediates building up along a reaction pathway is the use of low temperature conditions. Here, we report a kinetically competent system for the release of molecular oxygen at cryogenic temperature, using a cobalt-based caged oxygen molecule, (micro-peroxo)(micro-hydroxo)bis[bis(bipyridyl)cobalt(III)] nitrate. Cryophotolysis of this compound was induced using 266 nm laser light and monitored by absorption microspectrophotometry. Furthermore, to verify that photo-fragmentation was accompanied by release of the active caged molecule, the production of dioxygen during cryophotolysis was directly visualized. This work lays the foundations for the use of low temperature reaction triggering as a tool to prolong the lifetime of normally unstable intermediate states in oxygen-dependent enzymes.
authors.affiliation: Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, UK OX1 3TA. ahowardjones@med.usyd.edu.au
authors.forename: Annaleise R
authors.initials: AR
authors.lastname: Howard-Jones
authors.forename: Virgile
authors.initials: V
authors.lastname: Adam
authors.forename: Andrew
authors.initials: A
authors.lastname: Cowley
authors.forename: Jack E
authors.initials: JE
authors.lastname: Baldwin
authors.forename: Dominique
authors.initials: D
authors.lastname: Bourgeois
mesh_terms: D003080:Cold Temperature; D018360:Crystallography, X-Ray; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009566:Nitrates / Q000138:chemical synthesis / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010782:Photolysis
chemical_list: C095505:(mu-peroxo)(mu-hydroxo)bis(bis(bipyridyl)cobalt(III)) complex; D009566:Nitrates; D009942:Organometallic Compounds; D010100:Oxygen