Reaction force constant as a descriptor of the principle of non-perfect synchronization.

Context: In this study, a small set of 1,3-dipolar cycloaddition reactions that proceed at the same exothermicity is presented. Our main objective was to extend the application of the reaction force constant concept to gain an understanding of the reactivity principles. Inspired by a recent article where we show that the Bell-Evans-Polanyi principle is fulfilled under the condition of an equal degree of (a)synchronicity, here, we demonstrate that the reaction force constant is also a suitable descriptor to quantify the principle of non-perfect synchronization proposed by Bernasconi as a way to understand deviations from the Bell-Evans-Polanyi principle.

Stereocontrol of Metal-Centred Chirality in Rhodium(III) and Ruthenium(II) Complexes with NN'P Ligand.

Rh(III) and Ru(II) complexes, [RhCl(κ-NN'P-L)][SbF] (1) and [RuCl(κ-NN'P-L)] (2), were synthesised using the tetradentate ligand L (L=N,N-bis[(pyridin-2-yl)methyl]-[2-(diphenylphosphino)phenyl]methanamine). In each case only one diastereomer is detected, featuring cis-disposed pyridine groups. The chloride ligand trans to pyridine can be selectively abstracted by AgSbF, with the ruthenium complex (2) reacting more readily at room temperature compared to the rhodium complex (1) which requires elevated temperatures.

4-aminopyridine improves evoked potentials and ambulation in the taiep rat: A model of hypomyelination with atrophy of basal ganglia and cerebellum.

The taiep rat is a tubulin mutant with an early hypomyelination followed by progressive demyelination of the central nervous system due to a point mutation in the Tubb4a gene. It shows clinical, radiological, and pathological signs like those of the human leukodystrophy hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC). Taiep rats had tremor, ataxia, immobility episodes, epilepsy, and paralysis; the acronym of these signs given the name to this autosomal recessive trait.

Molecular Dihydrogen Activation by (CMe)M/N (M=Rh, Ir) Transition Metal Frustrated Lewis Pairs: Reversible Proton Migration to, and Proton Abstraction from, the CMe Ligand.

The masked transition-metal frustrated Lewis pairs [Cp*M(κN,N',N''-L)][SbF] (Cp*=η-CMe; M=Ir, 1, Rh, 2; HL=pyridinyl-amidine ligand) reversibly activate H under mild conditions rendering the hydrido derivatives [Cp*MH(κN,N'-HL)][SbF] observed as a mixture of the E and Z isomers at the amidine C=N bond (M=Ir, 3Z, 3E; M=Rh, 4Z, 4E). DFT calculations indicate that the formation of the E isomers follows a Grotthuss type mechanism in the presence of water. A mixture of Rh(I) isomers of formula [(Cp*H)Rh(κN,N'-HL)][SbF] (5 a-d) is obtained by reductive elimination of Cp*H from 4.

Dynamic Configuration on a Chiral-at-Rhodium Catalyst Featuring a Flexible Tetradentate Ligand.

The unique dynamic configuration of an enantioselective chiral-at-metal catalyst based on Rh(III) and a non-chiral tetradentate ligand is described and resolved. At room temperature, the catalyst undergoes a dynamic configuration process leading to the formation of two interconvertible metal-stereoisomers, remarkably without racemization. Density functional theory (DFT) calculations indicate that this metal-isomerization proceeds via a concerted transition state, which features a trigonal bipyramidal geometry stabilized by the tetradentate ligand.