title: Binding and photodissociation of CO in iron(II) complexes for application in positron emission tomography (PET) radiolabelling.
abstract: (R-DAB)FeI(2) complexes containing bidentate diimide ligands (R-DAB = RN=CH-CH=NR; R = (i)Pr, c-C(6)H(11)) have been investigated for their ability to react with carbon monoxide to form iron(II) dicarbonyl complexes, (R-DAB)FeI(2)(CO)(2). Solution IR spectroscopy revealed two νCO stretches between 2000 and 2040 cm(-1) corresponding to a cis-arrangement of the carbonyl ligands around the iron. Photochemical decarbonylation was achieved by UV irradiation (365 nm), which occurred within 5 min as evidenced by solution IR spectroscopy. (c-C(6)H(11)-DAB)FeI(2) has been characterised by X-ray crystallography. Reactions using (11)C-labelled carbon monoxide were investigated and revealed that both (R-DAB)FeI(2) species were not effective as trapping complexes due to the low concentrations of [(11)C]CO used in these experiments. A Fe(TPP)(THF)(x) (TPP = tetraphenylporphyrin) complex was investigated with unlabelled CO and the monocarbonyl adduct Fe(TPP)(THF)CO was formed in situ as identified by IR spectroscopy (νCO = 1966 cm(-1)) yet was stable to CO loss upon UV irradiation. Carbonylation reactions of in situ-generated Fe(TPP)(THF)(x) using [(11)C]CO revealed that 97% of the [(11)C]CO stream could be trapped in one pass of the gas at room temperature and at atmospheric pressure.
authors.affiliation: Department of Chemistry, Imperial College London, London, UK SW7 2AZ.
authors.forename: Chloe R
authors.initials: CR
authors.lastname: Child
authors.forename: Steven
authors.initials: S
authors.lastname: Kealey
authors.forename: Harriet
authors.initials: H
authors.lastname: Jones
authors.forename: Philip W
authors.initials: PW
authors.lastname: Miller
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: White
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Gee
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Long
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry*; D002250:Carbon Radioisotopes / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D008968:Molecular Conformation; D010782:Photolysis; D049268:Positron-Emission Tomography; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002250:Carbon Radioisotopes; D056831:Coordination Complexes; D005296:Ferrous Compounds; D002248:Carbon Monoxide