124354-44-5Relevant academic research and scientific papers
Redox interconversion of [RevO]3+?[ReIII]3+ centers in octahedral 4,6-dimethyl-pyrimidine-2-thiolate/triphenylphosphine rhenium(V) and rhenium (III) mixed complexes
Battistuzzi, Gianantonio,Borsari, Marco,Battistuzzi, Raffaele
, p. 2093 - 2104 (1997)
Reaction of trans-[ReOX2(EtO)(PPh3)2] (X = Cl, Br, I) with 4,6-dimethylpyrimidine-2-(1H)-thione (pymSH) in 1:1 molar ratio in refluxing acetone, rapidly formed [ReOX2(pymS) (PPh3)] (X = Cl, Br, I) compounds and PPh3 in good yields. Upon increasing the refluxing time (5-6 h), the above products react in a 1:2 molar ratio producing the paramagnetic trans-[ReX2(pymS)(PPh3)2] (X = Cl, Br) species and triphenylphosphine oxide as a result of oxygen transfer from the [ReO]3+ core to the PPh3. The trans-[ReX2(pymS) (PPh3)2] (X = Cl, Br) species, in organic solvents at room temperature and in the presence of atmospheric oxygen, are easily oxidized back to [ReOX2(pymS)(PPh3)] with the concomitant formation of O = PPh3. These oxidation reactions most likely proceed through the loss of a PPh3 ligand on the reducing rhenium(III) center, which makes a coordination site available for the oxidative addition of dioxygen which produces a highly reactive rhenium-dioxygen intermediate ([ReX2(pymS)(PPh3(O2)]). The time course of the aerial oxygenation reactions at room temperature was inferred from the rate [Km = (1.30 ± 0.05) × 10-2 h-1] of disappearance of the paramagnetic trans-[ReX2(pymS)(PPh3)2] (X = Cl, Br) species, monitored by VIS-NIR and 1H NMR spectroscopy. Spectroscopic (UV-VIS-NIR. 1H and 31P NMR), magnetic and electrochemical properties of the complexes are discussed.
Synthesis, structural, and spectroscopic study of rhenium(III) and rhenium(V) 4,6-dimethylpyrimidine-2-thiolate/triphenylphosphine mixed complexes: Crystal and molecular structure of *C3H6O and
Battistuzzi, R.,Manfredini, T.,Battaglia, L. P.,Corradi, Bonamartini, A.,Marzotto, A.
, p. 513 - 534 (2007/10/02)
4,6-dimethylpyrimidine-2(1H)-thione reacts with rhenium(V) precursors trans (X = Cl, Br) in acetone, to afford two classes of crystalline pyrimidinethiolate/triphenylphosphine mixed complexes: trans-IIIX2(C6H7N2S)(PPh3)2>*C3H6O and VOX(C6H7N2S)(PPh3)> (X = Cl, Br).The crystal structures of trans-*C3H6O (I) and (II) have been determined from single-crystal diffractometer data and refined to R factors of 0.0496 and 0.0365, respectively. (I) crystallizes in the triclinic space group P with a = 16.875(4), b = 13.969(7), c = 9.510(2) Angstroem, α = 81.78(2) deg, β = 85.15(12) deg, γ = 107.97(8) deg and Z = 2.The coordination geometry around the rhenium center exhibit mutually trans phosphine groups and chloride ligands disposed trans to the nitrogen and sulfur donors of the pyrimidine thiolate ligand which form a four-membered chelate ring with the metal. (II) crystallizes in the monoclinic spase group P21/c with a = 12.554(3), b = 10.501(1), c = 19.200(5) Angstroem; β = 106.54(2) deg and Z = 4.The rhenium atom presents a very distorted octahedral configuration with a chlorine atom trans to phosphine ligand in the axial position and the N,S-chelate ligand in the equatorial plane with the sulfur donor atom trans the Re=Ooxo group.The compounds were characterized also by means of ir and nmr spectroscopic measurements; reaction pathways are discussed on the basis of structural data.
