Understanding thio-effects in simple phosphoryl systems : role of solvent effects and nucleophile charge.

Recent experimental work (J. Org. Chem., 2012, 77, 5829) demonstrated pronounced differences in measured thio-effects for the hydrolysis of (thio)phosphodichloridates by water and hydroxide nucleophiles. In the present work, we have performed detailed quantum chemical calculations of these reactions, with the aim of rationalizing the molecular bases for this discrimination. The calculations highlight the interplay between nucleophile charge and transition state solvation in SN2(P) mechanisms as the basis of these differences, rather than a change in mechanism

BRS Cohomology of Zero Curvature Systems II. The Noncomplete Ladder Case

The Yang-Mills type theories and their BRS cohomology are analysed within the zero curvature formalism.Comment: 14 pages, latex, no figures, latex improve

A new perspective on the quaternionic numerical range of normal matrices

A new geometric proof of a known result characterizing the quaternionic numerical range of normal matrices is proposed. Our proof can be interpreted in probabilistic terms.info:eu-repo/semantics/acceptedVersio

On the convexity and circularity of the numerical range of nilpotent quaternionic matrices

We provide a sufficient condition for the numerical range of a nilpotent matrix N to be circular in terms of the existence of cycles in an undirected graph associated with N. We prove that if we add to this matrix N a diagonal real matrix D, the matrix D+N has convex numerical range. For 3 x 3 nilpotent matrices, we strength further our results and obtain necessary and sufficient conditions for circularity and convexity of the numerical range.info:eu-repo/semantics/publishedVersio

Axial Multicentric Osteosarcoma in an English Cocker Spaniel

No abstract available