Journal of Inorganic and Nuclear Chemistry最新文献

Ionisation energies have been determined for N₃P₃F_nX_6−n where n = 2, 3 and 4 and X = Br, Cl or NMe₂, using an electron impact ion source and the semi-logarithmic plot method. Results are compared with values for N₃P₃X₆ where X = Br, Cl, F or NMe₂. The substitution of dimethylamino groups for fluorines in N₃P₃F₆ causes a marked decrease in ionisation energy. A similar though less pronounced decrease occurs on substitution of fluorine by bromine or chlorine. The appearance energies were determined for several fragment ions.

Reactions between tetrahydrofuran (THF) and 22 different perchlorate salts, most often in the presence of organic halides were studied. The use of the organic halides including acetyl, benzoyl and substituted allyl chlorides aided in arranging the perchlorates according to their ability to give good yields of tertiary oxonium ion and polymer from THF. The approximate order, based on the yield of poly(tetrahydrofuran) obtained after 24 hr was Ag⁺, Hg²⁺ > Pb²⁺, Tl³⁺ > Fe³⁺, Al³⁺, Na⁺, Fe²⁺ > Cr³⁺, Mn²⁺, Ni²⁺, Cu²⁺, Co²⁺, Cd²⁺ ⪢ Ce³⁺, Mg²⁺, Ca²⁺, Ba²⁺, Zn²⁺, Li⁺, K⁺, NH₄⁺ = 0. Only Ag⁺ and Hg²⁺ perchlorates gave polymer when allylhalides were used. With one other perchlorates the order of reactivity of the halide was acetyl > benzoyl ⪢ allyl = 0.

The kinetics of the substitution reaction between aquo cupric ion and the nickel(II) complex of ethylene-bis-N,N′-(2,6-dicarboxy)-piperidine (NiEBDP) have been measured, as well as the equilibrium constants associated with the protonation of the metal ion complexes and the rapid formation of dinuclear complexes. The rate data can be expressed by the following rate law: $\text{−}\text{d[NiEBDP]}{}_{\mathrm{T}}\text{d}\text{t}\text{=}\text{k}{}^{\mathrm{<mtext>NiEBDP</mtext>}}{}_{\mathrm{<mtext>Cu</mtext>}}\text{[Cu}{}^{\mathrm{2+}}\text{]+k}{}^{\mathrm{<mtext>NiEBDP</mtext>}}{}_{\mathrm{<mtext>H</mtext>}}\text{[H}{}^{\mathrm{+}}\text{]+k}{}^{\mathrm{<mtext>NiEBDP</mtext>}}{}_{\mathrm{<mtext>Cu,H</mtext>}}\text{[Cu}{}^{\mathrm{2+}}\text{][H}{}^{\mathrm{+}}\text{]}\text{[}\text{NiEBDP}{}^{\mathrm{2-}}\text{].}$ Values of rate constants (25.0°C, μ = 1.25), enthalpies and entropies of activation for the reaction pathways are: k_Cu^NiEBDP, 2.77 × 10⁻²M⁻¹ sec⁻¹, 11.7 kcal/mole, −26.4 cal mole⁻¹ K⁻; k_H^NiEBDP, 3.33 × 10⁻²M⁻¹ sec⁻¹, 14.8 kcal/mole, −15.6 cal mole⁻¹ K⁻¹; and k_Cu.H^NiEBDP, 4.47 × 10⁺¹M⁻¹, 13.9 kcal/mole, −4.3 cal mole⁻ K⁻¹, respectively. The results are interpreted in terms of steric effects arising from the ring structure of the ligand by comparison to kinetic studies of similar systems.

Monomeric and polymeric iron phthalocyanines (FePc) with and without carbon support and subjected to various heat treatments have been studied by Mössbauer spectroscopy. Dispersing FePc on carbon changes the electronic state of the monomer to low spin (S = 0) while the electronic state of the polymer remains unchanged (S = 1). It is suggested that the bonding between polymeric FePc and carbon takes place through the side groups present on the peripheral parts of the polymer and/or through suitable chemical groups present on the carbon surface. The electron-attracting ability of the side-groups deduced from the Mössbauer spectra is discussed. The results will form a basis for a comparison with data from electrochemical measurements.

The yields of 40 fission products for the ²⁴⁹Cf (n_th, f) reaction have been determined. The yields are compared with those determined previously and a composite mass distribution is deduced with the average mass for the light group $\text{A}{}_{\mathrm{L}}$ equal to 105.9±0.2 and for the heavy group $\text{A}{}_{\mathrm{H}}$ equal to 140.0±0.2. The peak-to-valley ratio $\text{P}\text{V}$ is ∼ 26. Four new yields for the spontaneous fission of ²⁵⁰Cf have also been determined. The characteristics for this mass distribution are $\text{A}{}_{\mathrm{L}}\text{= 105.4±0.2,}\text{A}{}_{\mathrm{H}}\text{= 141.6±0.2}$, and $\text{P}\text{V}\text{⪖ 310}$.

Copper(II) complexes have been prepared with 2-isopropylaminopyridine N-oxide (IP) employing the perchlorate, tetrafluoroborate, nitrate, chloride and bromide salts. Preparative molar ratios of 4:1 and 2:1 ligand to copper(II) salt yielded the following unique salts: Cu(IP)₄X₂(X=ClO₄⁻, BF₄⁻), Cu(IP)₃(NO₃)₂ and Cu(IP)₂X₂(X=NO₃⁻, Cl⁻ and Br⁻). Characterization and has been accomplished by infrared, electronic and electron spin resonance measurements primarily of the solid state. IP bonds as a monodentate ligand via its N-oxide oxygen in the first three complexes, but apparently as a bidentate ligand in the latter three. Cu(IP)₂(NO₃)₂ is binuclear and anion coordination occurs in both of the nitrate complexes as well as both halogen solids.

The preparation of the complex Fe(ppi)₃(NCS)₂ (where ppi = N-phenyl-2-pyridinaldimine) is described. Mössbauer and magnetic susceptibility of this compound was studied in the temperature range between 298 and 78 K and clearly indicate a temperature induced $\text{high-spin}\text{(}{}^5\text{T}{}_2\text{)-}\text{low-spin}\text{(}{}^1\text{A}{}_1\text{)}$ transition.

The mass-yield dependence of (γ,n) and (γ,p) reactions in the photon energy range (0.2–1) GeV has been investigated. A Monte Carlo calculation for these reactions has been carried out to compare values of the measured cross sections with those arising from different models of interaction. Very good agreement was found between experiment and estimates based on a fast-step, direct character for the reaction mechanism. As a result of the analysis, N- and Z-dependences of mean cross sections are given for the (γ,n) and (γ,p) reactions. Agreement with a more sophisticated theory is also quite reasonable.