Activation of molecular oxygen by a dioxygenase pathway by a ruthenium bis-bipyridine compound with a proximal selenium site.
A ruthenium(II) bipyridine complex with proximal phenylselenium tethers, [Ru](H(2)O)(2), reacted intramolecularly with O(2) in a protic slightly acidic solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), to yield an O-O bond cleaved product, [Ru](O)(2), with formation of two Ru-O-Se moieties. This stable compound was isolated, and its structure was determined by X-ray diffraction. The identification of the compound in solution was confirmed by ESI-MS and the (1)H NMR with the associated Curie plot that showed that [Ru](O)(2) was paramagnetic. The magnetic susceptibility was 2.8 mu(B) by Evan's method suggesting a ground state triplet or biradical. DFT calculations, however, predicted a ground state singlet and an oxidized Se atom. Further it was shown that [Ru](O)(2) is a potent oxygen transfer species of both O(2)-derived atoms to triphenylphosphine and a nucleophilic alkene such as 2,3-dimethyl-2-butene in both HFIP and acetonitrile. UV-vis spectroscopy combined with the measured stoichiometry of PPh(3):O(2) = approximately 2 in a catalytic oxidation of PPh(3) suggests a dioxygenase type activation of O(2) with structural identification of the O-O bond cleavage reaction step, formation of [Ru](O)(2) as an intermediate, and the proof that [Ru](O)(2) is a donor of both oxygen atoms.
Laskavy
Alexander
A
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100.
Shimon
Linda J W
LJ
Konstantinovski
Leonid
L
Iron
Mark A
MA
Neumann
Ronny
R
D001665:Binding Sites; D018360:Crystallography, X-Ray; D049308:Dioxygenases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D011725:Pyridines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry*
D009942:Organometallic Compounds; D011725:Pyridines; D012428:Ruthenium; D049308:Dioxygenases; D012643:Selenium; D010100:Oxygen