title: Photochemistry of trans-Cr(cyclam)(ONO)2+, a nitric oxide precursor.
abstract: Experimental and density functional theory (DFT) studies are described that are focused on outlining the reactivity of the known photochemical nitric oxide precursor trans-Cr(cyclam)(ONO)(2)(+) ("CrONO", cyclam = 1,4,8,11-tetrazacycltetradecane). Studies in both aerated and deaerated aqueous media are described as are the roles of both the oxidant O(2) and a reductant such as glutathione in trapping the apparent Cr(IV) photoreaction intermediate trans-Cr(cyclam)(O)(ONO)(+). Also reported and characterized structurally is the Cr(V) product of long-term photolysis in the absence of reducing agents, the trans-dioxo species [trans-Cr(cyclam)(O)(2)](ClO(4)). Photosensitization experiments indicate that at least a significant fraction of the reaction occurs from the lowest energy doublet excited state(s). Lastly, cell culture experiments demonstrate that CrONO has little or no acute toxicity either before or after photolysis.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106-9510, USA.
authors.forename: Alexis D
authors.initials: AD
authors.lastname: Ostrowski
authors.forename: Ryan O
authors.initials: RO
authors.lastname: Absalonson
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: De Leo
authors.forename: Guang
authors.initials: G
authors.lastname: Wu
authors.forename: James G
authors.initials: JG
authors.lastname: Pavlovich
authors.forename: Janet
authors.initials: J
authors.lastname: Adamson
authors.forename: Bilal
authors.initials: B
authors.lastname: Azhar
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Iretskii
authors.forename: Ian L
authors.initials: IL
authors.lastname: Megson
authors.forename: Peter C
authors.initials: PC
authors.lastname: Ford
mesh_terms: D045744:Cell Line, Tumor; D002857:Chromium / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008027:Light; D015394:Molecular Structure; D058990:Molecular Targeted Therapy / Q000379:methods; D009000:Monocytes / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods; D010782:Photolysis / Q000187:drug effects / Q000528:radiation effects; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D010789:Phototherapy / Q000379:methods; D011355:Prodrugs / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D006571:Heterocyclic Compounds; D017319:Photosensitizing Agents; D011355:Prodrugs; D002857:Chromium; C024560:cyclam; D009569:Nitric Oxide; D007770:L-Lactate Dehydrogenase; D005978:Glutathione