Novel redox active bifunctional crosslinkers from unsymmetrical 1,1′-disubstituted ferrocenes

The synthesis and electrochemistry of novel redox active bifunctional crosslinkers bearing pendant amine and maleimide groups from unsymmetrical 1,1′-disubstituted ferrocene precursors are reported.     

Déformations formelles de revêtements: un principe local-global

LetC be a generically smooth, locally complete intersection curve defined over an algebraically closed fieldk of characteristicp≥0. LetG⊃ Aut _k C be a finite group of automorphisms ofC. We develop a theory ofG-equivariant deformations of the Galois coverC→C/G. We give a thorough study of the local obstructions, those localized at singular or widely ramified points, to deform equivariantly a cover. As an application, we discuss the case ofG-equivariant deformations of semistable curves.      

Non-involutive constrained systems and Hamilton-Jacobi formalism

In this work we discuss the natural appearance of the Generalized Brackets in systems with non-involutive (equivalent to second class) constraints in the Hamilton-Jacobi formalism. We show how a consistent geometric interpretation of the integrability conditions leads to the reduction of degrees of freedom of these systems and, as consequence, naturally defines a dynamics in a reduced phase space.     

Transitions and Spin Dynamics at Very Low Temperature in the Pyrochlores Yb2Ti2O7 and Gd2Sn2O7

An orientational disorder of the cation in [(PyO)D][AuCl₄] crystal was investigated by the ³⁵Cl NQR and ¹H NMR measurements. A structural phase transition was found at ca. 70 K from the temperature dependence of the NQR frequencies both in [(PyO)D][AuCl₄] and [(PyO)H][AuCl₄]. Temperature dependence of the spin-lattice relaxation time T ₁ of the NQR of [AuCl₄]⁻ could be interpreted by an electric field gradient modulation due to the motion of the cation. Characteristics of T ₁ of ³⁵Cl NQR as well as that of ¹H NMR suggest a dynamic orientational disorder of the cation.     

On the unimodality of discrete probability measures

This work was supported by the Natural Sciences and Engineering Research Council of Canada and by the Fonds F.C.A.R. of the Province of Quebec, Canada     

Comment on Ihle, “Towards a quantitative kinetic theory of polar active matter”

A comment on the contribution of T. Ihle [1] in this special issue.     

Electron driven processes in ices: Surface functionalization and synthesis reactions

The ability to control and orientate chemical reactivity in the condensed phase is a major challenge of modern research. Upon interaction with condensed molecules electrons drive bond cleavage thus generating a population of very reactive species in the condensed medium. These reactive species may interact either within the volume leading to the synthesis of new molecules or with the substrate surface by forming strong chemical bonds. The former reaction is known as electron induced synthesis and the latter one as electron induced surface functionalization.High-energy electrons achieve only a low chemical specificity due to the large number of dissociating open channels. In contrast, electrons with energies below ionization threshold of the irradiated matter are capable of high selectivity because of the dissociative electron attachment mechanism.In this review recent studies of electron interaction with condensed molecules on hydrogenated diamond substrates will be described. In particular electron induced functionalization of diamond surfaces by CH₂CN groups, decarboxylation reactions in condensed films of pure organic acids RCOOH (R = H, CH₃, C₂H₅, CF₃), carbamic acid formation in CO₂:NH₃, HCOOH:NH₃ and CF₃COOH:NH₃ binary ice mixtures, and glycine formation in a CH₃COOD:NH₃ mixture are presented and discussed.