Claude Sirlin

Ion channel containing mesophases: structural characteristics of condensed phases of crown-ether-substituted phthalocyanines

Abstract A copper complex of a phthalocyanine substituted with four benzo-15-crown-5 1,Cu and the corresponding dihydrogeno-derivative 1,H2 were synthesized. X-ray determinations at small angles permitted us to characterize two types of condensed phases. Solid phases with orthorhombic structure were found for 1,H2 and for 1,Cu (a=20.5, b= 18, c=4.2 A). In these forms, two-dimensional rectangular arrays of substituted phthalocyanines lead to corrugated planes. Phthalocyanine moieties are superposed in an eclipsed conformation and the crown-ether macrocycles form channels. Metastable mesophases could also be characterized by X-ray diffraction. In this case, only two broad lines at 20.8 and 8.2 A and two halos at 3.5 and 4.2 A are observed for 1,Cu. The dihydrogeno-derivative leads to a similar pattern but only one halo is noticed at 4.2 A. The mesophases are constituted of two-dimensional square lattices superposed in a staggered conformation.

Cycloruthenated compounds as efficient catalyst for asymmetric hydride transfer reaction

Cycloruthenated complexes obtained by direct C-H activation of enantiopure aromatic primary and secondary amines are efficient catalysts in asymmetric hydride transfer reaction. Reduction of acetophenone has been achieved rapidly with enantiomeric excesses (ees) ranging from 38 to 89 %. The importance of Ru-C bond in the catalytic efficiency is highlighted.

Molecular Recognition of Anions by a Novel Organocobalt Receptor: Oxyanion versus Halide Selectivity in Water

The dissolution of [Co{2,6-(Me2NCH2)2C6H3}(η5-C5H5)(H2O)]PF6 (1a) in dry methanol or dry acetonitrile affords compounds 1b and 1c, respectively, in which the water ligand of 1a has been substituted by MeOH or by CH3CN. The crystal structure analysis of 1b established that a strong intramolecular interaction exists between the methanolic proton and the NMe2 group that was interacting with H2O in 1a. For 1c no interaction could be found between the Co-bound acetonitrile ligand and this NMe2 as it has changed its position in order to be as far away from the cobalt atom as possible. Whereas no reaction takes place between 1a and an excess of sodium iodide in water or in methanol, in acetone I− easily substitutes the water ligand of 1a to afford high yields of the neutral compound 3. Here also 1H NMR spectroscopic data are in favour of a structure with no interaction between the NMe2 and the iodide ligand as in 1c. Protonation of the free NMe2 unit of 1a by adding increasing amounts of HPF6 in water leads to the synthesis of 4a. The pKa of 1a in D2O was found to be 6.1. Treating 1a with acidic buffered water solutions (pH = 5.5) leads to the in situ formation of 4a. From these solutions, association constants were determined for Cl−, Br−, I−, AcO−, H2PO4− and NO3−. Significant selectivity in water for AcO− and H2PO4− vs. halide anions has been established. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Palladium‐Catalysed Synthesis of Dibenzo[de,g]quinolines. A Novel Approach to the B‐Ring System of Aporphine‐Related Heterocycles

Dibenzo[de,g]quinolines 5were formed by the palladium-catalysed heteroannulation of disubstituted alkynes and 1-iodo-10-(dimethylamino)phenanthrene (3c). Symmetric alkynes led to high levels of regioselectivity. These reactions constitute a new synthesis of the B-ring system of aporphine heterocycles.

Palladium-assisted intramolecular formation of n-heterocycles by sp2 N nucleophilic attack on η3-allyl-Pd complexes generated by allene insertion into σ PdC bond

Abstract 1,1-dimethylallene inserts into the σ PdC bond of a series of cyclopalladated pyridine derivatives leading to stable or unstable η 3 -allyl-Pd complexes. The demetallation of the latter leads to pyridinium derivatives with good yields.

Cycloruthenated tertiary amines and ethylene: further insight to the Ru-mediated olefin–aryl coupling reaction

The reaction between cycloruthenated N,N-dimethylbenzylamine and ethylene under very mild conditions afforded 2-vinyl-N,N-dimethylbenzylamine and an organometallic Ru derivative resulting from the overall insertion of one carbon atom in the Ru–C bond of the starting material.