Search

Die Geschwindigkeitskonstanten der spontanen Ringoffnung der Titelverbindungen (I) und (II) sowie der Vergleichs-epoxide (III) und (IV) in Wasser bzw. wasrigem Dioxan betragen (0.032-8.5)·10-5/s, die der saurekatalysierten Reaktion 0.13-1200/s. Es wird gefolgert, das mit Abnahme der protischen Natur des Losungsmittels die beschleunigende Wirkung interner H-Bindungen an Bedeutung gewinnt.

Peroxodisulphate oxidation of a silver(I) complex of 5,10,15,20-tetra(3′-N-methylpyridinio)-porphyrin, believed to be 2:1 (metal : ligand), to the silver(II) complex has been investigated at 25 °C and I= 0.1 mol dm–3. This reaction was found to be first order each in silver(I) and peroxodisulphate ions and zero order in porphyrin. The second-order rate constant for the oxidation is computed to be 3.45 × 10–2 dm3 mol–1 s–1, which is in agreement with independently determined rate constants for the reaction of Ag+ with S2O82–.

The preparation of the orange diamagnetic compounds [MoO(S2CNR2)3]X (R = Me or Et, X = BF4–, PF6–, or ClO4–; R = Pri, X = BF4–) from the reaction of cis-[MoO2(S2CNR2)2] complexes and HX in acetone is described. Details of the 1H and 13C-{1H} n.m.r., i.r., and electronic spectra of the complexes are presented. The monomeric complex cations possess a rigid pentagonal-bipyramidal geometry in solution at room temperature. The complex [MoO(S2CNEt2)3]+ catalytically converts PPh3 into OPPh3 in air, gives [Mo(NPh)(S2CNEt2)3]}+ with PhNCO, undergoes replacement of one S2CNEt2– ligand with Cl– and S22–, and yields [MoO(S2CNEt2)2] upon reduction.

Etude par diverses techniques de luminescence. On suit la relation pH-intensite de luminescence et temps de vie en fonction du rapport metal: coordinat. Dans la plupart des cas l'ion lanthanide prefere une coordinence 10

On montre que 18=crown-6 (L) a une forte influence sur le cours de plusieurs reactions mettant en jeu K 4 Ni(CN) 4 , malgre sont manque d'efficacite. Comme solubilisant de KuNi(CN) 4 dans l'acetonitrile. Ainsi on etudie la formation de (K + −L) 2 [Ni(CN) 2 (PhC≡CPh)] et [(η 2 −PhCH=CHCN) Ni(CN) 2 2 ] (K−L) 2

Impressive progress has been made in the last twenty five years in understanding the detailed nature of chemical processes involving a few atoms at a time, as honored in the recent Nobel Prize to Herschbach, Lee and Polanyi. Unfortunately, most processes of interest to most chemists involve the simultaneous interaction of many atoms. Examples include all of liquid solution chemistry (and thus most of inorganic and organic chemistry) and chemistry involving large molecules (and thus most of polymer chemistry and biochemistry). A realistic assessment of many atom chemistry in general and liquid solution chemistry in particular is that we know very little as yet about the microscopic details of such processes. Given the clear importance of solution chemistry, it is surprising that so little is known about liquid state solution reactions from the fundamental viewpoint of how they take place as seen from the microscopic perspective of molecular dynamics, in other words of the atomic motions by which they happen.