Reactions in [2H]3-acetonitrile between trimethyl phosphite copper(I) or iron(II) cations and phosphorus pentafluoride or tungsten hexafluoride [1]

Fluorination of trimethyl phosphite in reactions between phosphorus pentafluoride or tungsten hexafluoride and the cations Cu[P(OMe)₃]₄⁺ or [FeP(OMe)_3n(NCMe)_6?n]²⁺, n=5 or 4, in [²H]₃-acetonitrile is influenced both by the metal and by the solvent. Mixtures of phosphorus(III and V) and tungsten(VI) fluorides are obtained whose origin can be understood in terms of kinetic control by Cu^I or Fe^II, labile and inert towards substitution respectively, and the Lewis base properties of CD₃CN. ¹⁹F and ³¹P n.m.r. spectroscopy was used to study the reactions and the n.m.r. parameters of PF₅·P(OMe)₃ are reported.     

Redox reactions involving rhenium and uranium hexafluorides,a convenient synthesis of β-uranium pentafluoride

Rhenium and uranium hexafluorides oxidise elemental iodine in iodine pentafluoride at ambient temperature to give the I₂⁺ cation. With UF₆ an additional reaction occurs to give β-uranium pentafluoride as one product, β-UF₅ is soluble in acetonitrile without disproportionation and is also formed from the reduction of UF₆ by MeCN. Copper, cadmium, and thallium metals are oxidised by ReF₆ in MeCN giving Cu^I, Cd^II, and Tl^I hexafluororhenates(V) but the reactions are complicated by reaction between ReF₆ and the solvent.     

Solid state reactions of organopentafluorosilicates with copper(I) and copper(II) salts

Two types of solid state reaction of K₂[RSiF₅] have been developed: (1) CuCl promoted homo coupling of alkenyl- and phenyl-silicates, and (2) formation of RH fraom alkyl- and alkenyl-silicates by heating with CuF₂·2H₂O.     

Complexes of gold(I), silver(I), and copper(I) with pentaaryl[60]fullerides

Gold(I), silver(I), and copper(I) phosphine complexes of 6,9,12,15,18-pentaaryl[60]fullerides 1a and 1b, namely, [(4-MeC(6)H(4))(5)C(60)]Au(PPh(3)) (2a), [(4-t-BuC(6)H(4))(5)C(60)]Au(PPh(3)) (2b), [(4-MeC(6)H(4))(5)C(60)]Ag(PCy(3)) (3a), [(4-t-BuC(6)H(4))(5)C(60)]Ag(PPh(3)) (3b), [(4-t-BuC(6)H(4))(5)C(60)]Ag(PCy(3)) (3c), [(4-MeC(6)H(4))(5)C(60)]Cu(PPh(3)) (4a), and [(4-t-BuC(6)H(4))(5)C(60)]Cu(PPh(3)) (4b), have been synthesized and characterized spectroscopically. All complexes except for 3c were also characterized by single-crystal X-ray diffraction. Several coordination modes between the cyclopentadienyl ring embedded in the fullerene and the metal centers are observed, ranging from η(1) with a slight distortion toward η(3) in the case of gold(I), to η(2)/η(3) for silver(I), and η(5) for copper(I). Silver complexes 3a and 3b are rare examples of crystallographically characterized Ag(I) cyclopentadienyls whose preparation was possible thanks to the steric shielding provided by fullerides 1a and 1b, which stabilizes these complexes. Silver complexes 3a and 3b both display unexpected coordination of the cyclopentadienyl portion of the fulleride anion with Ag(I). DFT calculations on the model systems (H(5)C(60))M(PH(3)) and CpMPH(3) (M = Au, Ag, or Cu) were carried out to probe the geometries and electronic structures of these metal complexes.     

Redox chemistry of [Fe2(CN)10]4−. Part I. Reaction with iodide

The iron(III) dimeric complex [Fe₂(CN)₁₀]⁴⁻ is reduced to the iron(III)iron(II) species [Fe₂(CN)₁₀]⁵⁻ by iodide ion, the equilibrium constant being strongly dependent upon the nature of the alkali metal cation, reduction being favoured in the sequence: Cs⁺>NH ₄ ⁺ ≥K⁺>Na⁺>Li⁺. The reaction kinetics are autocatalytic in character, the catalytic species being the mixed valence dimer. The rates of reactions are also strongly catalysed by alkali metal cations, in the same sequence as for the equilibrium constants. The reaction mechanism involves the formation of I ₂ ⁻ as a reactive intermediate which can be oxidised by both [Fe₂(CN)₁₀]⁴⁻ and [Fe₂(CN)₁₀]⁵⁻.     

Some reactions of copper(I) pentafluorothiophenolate

Copper(I) pentafluorothiophenolate, CuSC₆F₅ reacted with a number of acyl and alkyl halides in either $\text{n}$-hexane or DMF. The products RCH₂SC₆F₅ (R = Me, Ph, C₆F₅S, C₆F₅SCH₂), Ph₂CHSC₆F₅, R₃CSC₆F₅(R =Me, Ph) and RCOSC₆F₅ (R = Me, C₆F₅) have been characterized and their spectra, particularly NMR spectra (H1, C13, F19) have been examined.     

Oxidation of molecular bromine by uranium hexafluoride in acetonitrile. Preparation and properties of hexafluorouranates(V) containing positive bromine

Molecular bromine is oxidized by uranium hexafluoride in acetonitrile at ambient temperature. The product is formulated on the basis of its spectra, and its brominating an oxidizing abilities as [Br(C₆H₉N₃)][UF₆] in which bromine is bound to an acetonitrile trimer containing C=N bonds.     

Trinuclear Schiff base complexes with uranium(V) and copper(II) or zinc(II) ions

Treatment of the uranium(IV) complexes [{ML¹(py)}₂U^IV] (M = Cu, Zn; L¹ = N,N′-bis(3-hydroxysalicylidene)-1,3-propanediamine) with silver nitrate in pyridine led to the formation of the corresponding cationic uranium(V) species which were found to be thermally unstable and were converted back into the parent U^IV complexes; no electron transfer was observed in solution between the U^IV and U^V compounds. In the crystals of [{ML¹(py)}₂U^IV][{ML¹(py)}₂U^V][NO₃], the neutral U^IV and cationic U^V species are clearly identified by the distinct U–O distances. Similar reaction of [{ZnL²(py)}₂U^IV] [L² = N,N′-bis(3-hydroxysalicylidene)-1,4-butanediamine] with AgNO₃ gave crystals of [{ZnL²(py)}U^V{ZnL²(py)₂}][NO₃] but the copper counterpart was not isolated. Crystals of [{ZnL¹(py)}₂U^V][OTf] · THF (OTf = OSO₂CF₃) were obtained fortuitously from the reaction of [Zn(H₂L¹)] and U(OTf)₃.     

Calculated optical and magnetic properties of hexafluorouranate (V) anion: UF- 6

Our ab initio all-electron Dirac-Fock and the corresponding nonrelativistic limit calculations performed at four U-F bond distances yield for octahedral UF(6) (-) the optimized U-F bond distance of 2.091 and 2.088 A, respectively. We have also performed Dirac scattered wave calculations at the optimized U-F bond distances using the first-order pertubational procedure to obtain the Zeeman and hyperfine magnetic tensors for the octahedral anion UF(6) (-). The calculated isotropic Zeeman tensor of Deltag=-2.87 is in fairly good agreement with the value of Deltag=-2.78+/-0.10 obtained in electron spin resonance experiments on the H(3)O(+)UF(6) (-) adduct and the unpaired electron-spin spends approximately 2.5% of its time on the fluorine 2p(3/2) spinors. The calculated relativistic transition energies of the near-IR and visible absorption bands are also in good agreement with the experimental results. The octahedral uranium hexafluoride anion has a simple crystal field f(1) configuration; however, relativistic four-component wave functions are necessary to interpret correctly the available magnetic data, while a relativistic treatment taking into account double group symmetrized basis functions should suffice for the interpretation of the optical data.     

Copper(I) coordination compounds with two bidentate chelating pyrazole ligands. X-ray crystal structures of DI-μ-chloro-bis[[N,N-bis(1- pyrazolylmethyl)aminoethane]copper(I)] and [bis(N,N-bis(1-pyrazolylmethyl)aminoethane]copper(I) triflate

The pyrazole derivatives of aminoethane N,N-bis(3,5-dimethyl-1-pyrazolyl- methyl)aminoethane (aebd) and N,N-bis(1-pyrazolylmethyl)aminoethane (aebp) form co- ordination compounds with copper(I) of stoichiometry [Cu(L)X], with X = Cl, Br, I and SCN, and [Cu(L)₂X], with X = CF₃SO₃ and BF₄. The ligands chelate in a bidentate manner, with only the pyrazole groups coordinating. The crystal structures of two representative examples have been determined: [Cu(aebp)Cl]₂ is triclinic, space group P , with a = 8.711(2), b = 9.351(1) and c = 9.528(1) Å, = 68.57(1)°, β = 61.47(1)° and γ = 77.82(1)°, and Z = 2. Standard least-squares refinement gave R = 0.029 (R_w = 0.038) for 1804 reflections. [Cu(aebp)₂]CF₃SO₃ is monoclinic, space group P2₁/n, with a = 13.352(5), b = 14.663(3) and c = 15.752(4) Å, β = 117.49(3)°, and Z = 4. Standard least-squares refinement gave R = 0.029 (R_w = 0.032) for 1786 reflections. In both cases the copper environment is slightly-distorted tetrahedral. The chloride compound is dimeric with one ligand molecule (Cu---N distances of 2.011(2) and 2.047(2) Å) and two bridging chlorides per copper (Cu---Cl distances of 2.3874(8) and 2.4094(8) Å). With the non- coordinating triflate anion, a monomeric compound with two ligand molecules per copper was obtained (Cu---N distances of 2.018(4), 2.028(4), 2.049(4) and 2.050(4) Å).     

Radical reactions of tricyclo[4.1.0.02,7]heptane and 1-phenyltricyclo[4.1.0.02,7]heptane with trifluoromethyl (phenylethynyl) sulfone

Russian Journal of Organic Chemistry -     

Redox reactions of V(III) and Cr(III)picolinate complexes in aqueous solutions

Reactions of e_aq⁻, H-atoms, OH, (CH₃)₂COH, and CO₂⁻ radicals with V(III)picolinate and Cr(III)picolinate have been studied by the pulse radiolysis technique. The spectra of V(II)picolinate, V(IV)picolinate, Cr(II)picolinate, OH adduct of Cr(III)picolinate and Cr(IV)picolinate have been obtained and the rate constants of the reactions of various radicals with V(III) and Cr(III)picolinate have been determined. The implications of these results to the chemical decontamination of nuclear reactor systems are discussed.     

Aminoacetal derivative of calix[4]resorcinarene. Acid-base properties and reactions with copper(II) and lanthanum(III) in various media

Studies were carried out by means of pH-metry, spectrophotometry, and mathematic simulation of equilibria (program CPESSP) on the state, acid-base properties and complexing ability [with respect to copper(II) and lanthanum(III)] of calix[4]resorcinol with acetal groups in the aminomethyl substituent [H₈L: R¹ = C₇H₁₅, R² = CH₂N(CH₃)CH₂CH₂CH(OCH₃)₂] in water-alcohol solution [80 vol % of i-PrOH] and in solutions of nonionogenic and ionic surfactants [Triton X-100, Brij-35, sodium dodecyl sulfate]. In all environments protonated and deprotonated tetrameric, dimeric, and monomeric species were found (pH range 3–10.6). In the presence of sodium dodecyl sulfate dimer (H₈L)₂ did not form that was the main speciation form in the other solvents. The sodium dodecyl sulfate like also Brij-35 favors formation of a hexadecamer (H₈L)₁₆ (pH about 6.3–6.5) in relatively small maximum accumulation fractions, 20 and 16% respectively. The solubility of H₈L in acid medium in the presence of cetyltrimethylammonium bromide, and in the presence of sodium dodecyl sulfate in alkaline medium, originated from the formation of mixed cationic and mixed anionic aggregates respectively. In a water-alcohol solution six complexes of copper(II) were detected: four mononuclear, one binuclear, and one tetranuclear complex with neutral and deprotonated forms of the ligand. Lanthanum(III) formed nine mononuclear complexes and in general coordinated more ligands than copper(II) favoring association (aggregation) of the compound under study.     

Diels-Alder reactions of perfluorobicyclo[2.2.0]hex-1(4)-ene with aromatics

[reaction: see text] The title perfluoroalkene cycloadds to a variety of aromatic hydrocarbons, including benzene. It is the first alkene to yield a Diels-Alder adduct with benzene and is thus among the most potent dienophiles known.