273 research outputs found
Reactions of Carbon Suboxide with Rhodium(I) Complexes
No full textThe decomposition of carbon suboxide in the presence of two rhodium(I)-complexes leads to CO and C2O. With (PPh3)3RhCl, (1) and polymeric C2O are formed, with [(C8H14)2RhCl]2 the polymers (2) and cyclooctene. Pyridine can “dissolve” the Cl-bridge in (2); a dimer is formed
Reaction of trans-[Pt(H)(2)(PCy3)(2)] with C-60 reductive elimination of H-2 and formation of [Pt(PCy3)(2)(eta(2)-C-60)]
No full textReaction of trans-[Pt(H)2(PCy3)2], 1, with [60]fullerene at room temperature affords [Pt(PCy3)2(η2-C60)], 2, in nearly quantitative yield. The most probable reaction pattern is the insertion of a fullerene 6,6 junction onto a Pt-H bond yielding an η1 alkyl derivative which, after hydrogen extrusion, gives 2. On the other hand, addition of 1 to different electron-deficient olefins, such as dimethyl maleate and fumarate, furnishes mixtures of both η1 metal—alkyl and η2 metal—olefin derivatives. If tetrachloroethylene is used as 2π component, trans-[PtCl(H)(PCy3)2] forms exclusively
Reactivity of carbon suboxide towards metal complexes of nickel, manganese, and rhodium. Decarbonylation reaction and allene polynuclear rhodium complex formation.
No full textCatalisi asimmetrica: stereochimica della reazione di idrogenazione omogenea di olefine con complessi di rodio.
No full textMAGNETIC TREATMENT OF WATER AND SCALING DEPOSIT
No full textA series of experiments confirms that a suitable magnetic field is able to prevent scale deposit on water contining Ca+2 ions and carbonic species. The magnetic field acts inducing the precipitation of CaCO3 in crystalline form, (calcite or aragonite) that does not adhere to the walls and tubes, whereas amorphous CaCO3, which is formed in absence of the magnetic field, is responsible of the scale deposit. The nucleating effect of Fe ions on the formation of crystalline CaCO3, in the presence of the magnetic field, is discussed
Reactions of carbon suboxide with platinum(0) complexes.
No full textThe skeleton of carbon suboxide remains intact on reaction with two platinum complexes. With (PPh3)2Pt(C2H4) the metallacyclopropane (1) is formed; with (PPh3)2Pt(O2) the dioxametallacyclopentane (2)
A Quasi-Relativistic Density Functional Study of Structural and Electronic Properties of the Bis-Ketene Cis-[Pt{η3-C3H5}{η1-C(PPh3)CO}2]+
No full textQuasi-relativistic density functional calculations have been used to look into the molecular and electronic properties of cis-[Pt(η3-C3H5){η1-C(PPh3)(CO)}2]BF4. Numerical experiments have been run for both isomers compatible with IR and NMR outcomes. Binding energies and computed CCO stretching frequencies are very similar for both species, thus indicating their possible coexistence in solution. The comparison with homogeneous theoretical data pertaining to cis/trans-[Pt(η3-C3H5)2] and trans-[PtCl2{η1-C(PPh3)(CO)}2] provides a rationale of the [Pt(η3-C3H5){η1-C(PPh3)(CO)}2]BF4 low stability
Synthesis of a pyrone derivative from carbon suboxide and acetylacetone catalyzed by acetylacetonate-metal complexes.
No full textBis(pentane-2,4-dionate)-metal, M(acac)2, (where M = Zn, Co, Ni and Cu) reacts quickly and in high yield with carbon suboxide, C3O2, at the methine position. The reaction produces 1:2 adducts which are insoluble in all organic solvents. The reaction of these adducts with aqueous HCl forms 5-acetyl-2-hydroxy-6-methyl-4-pyrone (AHMP).
The above-mentioned metal-acetylacetonates also catalyze the addition of C3O2 to free Hacac, but Cr(acac)3, Fe(acac)3 and Mn(acac)3 do not.
The relative catalytic efficiency of these pentane-2,4-dionates was determined. A mechanism for these reactions is proposed
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