PMR study of mixed complexes of Co(II) in aqueous pyridine and aqueous acetonitrile solutions

Journal of Structural Chemistry -     

Cleavage of the cyclic substituent in the [B10H9O2C4H8]−, [B10H9OC4H8]−, and [B10H9OC5H10]− anions upon the interaction with negatively charged N-nucleophiles

The interaction of the [B₁₀H₉O₂C₄H₈]^?, [B₁₀H₉OC₄H₈]^?, and [B₁₀H₉OC₅H₁₀]^? anions with negatively charged N-nucleophiles has been studied. It has been shown that such reactions yield doubly charged substituted closo-decaborates with a nitrogen-containing group attached to the cluster through an alkoxyl spacer. Compounds with pendant NO₂ ^?, N₃ ^?, N(CO)₂C₆H₄ ^?, and NHC₆H₅ groups have been synthesized.     

Comparative study of relativistic density functional methods applied to actinide species AcO(2)(2+) and AcF(6) for Ac = U,Np

A two-component relativistic density functional method based on the Douglas-Kroll-Hess transformation has been applied to the actinyls and hexafluorides of U and Np. All-electron scalar relativistic calculations as well as calculations including spin-orbit interaction have been compared to results obtained with a pseudopotential approach. In addition, several exchange-correlation potentials have been applied to examine their performance for the bond lengths and vibrational frequencies of the title compounds. The calculations confirm the well-known accuracy of the LDA approach for geometries and frequencies, which is corroborated for the hexafluorides where gas phase experimental data are available. Comparison with results of accurate wave function based methods provides further confirmation of this finding. Gradient-corrected functionals tend to overestimate bond lengths and underestimate frequencies also for actinide compounds. The results obtained with Stoll-Preuss (small core) effective core potentials agree very well with those of all-electron calculations, while calculations with Hay-Martin large core pseudopotentials are somewhat less accurate. For all molecules and properties considered, spin-orbit effects have been found negligible concomitant with the closed-shell electronic structure of the U(VI) compounds and the open-shell situation of the Np(VI) compounds with a single valence f electron.     

Analytical properties of conformal invariant four point functions

On the basis of the known group theoretical structure of the conformal invariant four point functions in the case of identical scalar fields ?(x) of scale dimension d,

$\text{<0|?(x}{}_1\text{)?(x}{}_2\text{)?(x}{}_3\text{)?(x}{}_4\text{)|0〉 = [(x}{}_1\text{?x}{}_4\text{)}{}^2\text{(x}{}_2\text{?x}{}_3\text{)}{}^2\text{]}{}^{\mathrm{-d}}\text{g(A,B),}$

the analytical properties of g(A, B) as a function of the harmonic ratios A and B are investigated. By imposing the conditions of spectrality and locality, and using invariance under complex dilatations, it is shown that the function g(A, B) must be homomorphic in the whole complex A-plane and B-plane with exception of the values A=0 and A=∞, B arbitrary, and B=0 and B=∞, A arbitrary.