R. Perrin

Study of calixarenes-dyes. Structure of p-tetrakis(phenylazo)calix[4]arene

Abstract The first crystal structure of a calixarene-dye, that of p-tetrakis-(phenylazo)calix[4]arene, is presented in this work. Recrystallization of this purified substance in N,N-dimethylformamide afforded crystals suitable for X-ray diffraction. The compound crystallizes in the triclinic space groupe P1 with a = 14.477(3), b = 15.699(3), c = 11.251(5) A, x = 95.29(3), β = 89.94(3), γ = 112.35(2)°, and Dc = 1.290g/cm3 for Z = 2. Refinement based on 6932 observed reflections afforded a final R value of 0.089. These calixarene-N,N-dimethyl-formamide 1:1 crystals have a high density for a compound constituted only of hydrogen, oxygen and nitrogen atoms. This is due to the penetration of a benzylazo group of a calixarene molecule in the cavity of a neighbouring calixarene molecule. A hydrogen bond is established between the oxygen atom of the N,N-dimethylformamide and an oxygen atom of the calixarene; CH3…π interactions also exist between an aromatic nucleus of the phenylazo group and N,N-dimethylformamide...

A New Organic Solid State Reaction: Hydrogenation of Phenols

Abstract During the past fifteen years there has been a number of detailed studies devoted to the chemistry of organic molecular solids and made by a number of groups involving chemists and crystallographers. These workers were interested in the reactions of the organic solids subjected either to a physical agent like light or heat or to a chemical one which can be a solid, a liquid or a gas.1

Characterization of precursors of p-tert-butylcalix[6]arene synthesis. Mechanism of formation of p-tert-butylcalix[6]arene

Abstract Gutsche has proposed the existence of “hemicalixarenes” and “pseudocalixarenes” to explain the formation of calixarenes. The characterization and the quantitative determination of molecules present during the reaction, described in “Organic Synthesis”, have permitted us to determine the immediate precursors of p-tert-butylcalix[6]arene. The calix[6]arene could be due to cyclization of linear species named “pseudocalixarenes” and not due to duplication of molecules named “hemicalixarenes”.

Solid State Chemistry of Calixarenes and Supramolecular Systems with Calixarenes

Abstract Two aspects of the solid state chemistry of calixarenes are presented: in the first part the chlorination of isopropyl and tert-butylcalixarenes is studied, a mechanism is proposed. In the second part the thermal rearrangement of supramolecular systems p-isopropylcalix[4]arene-pxylene is discussed, the thermal decapsulation of the guest molecules is schematized.

PreferentiaI Polysubstitution in Organic Soid State Reactions

Abstract We have studied a number of reactions of chlorination and alkylation of phenols in a fluid phase and in the solid state. We show the predominance of the polysubstitution when phenols react in the solid state.

Complexes in the Naphthoquinone Series: Crystal Structures, Electronic Structures, Stability

Abstract It is shown that the charge transfer is negligible in the ground state for organic charge transfer complexes between phenols and quinones. Our objective Is to determine the origin of the stability of the complexes. The geometric, electronic and energetic properties of these complexes were examined by three techniques, crystal structure determination by X-ray diffraction, spectrum and charge transfer calculation by quantum chemical methods, and lattice energy computation.

Principle of the accessibility to reactive centers in gas-organic solide reactions. Applications to the chlorination of supramolecular systems

The principle of the accessibility to reactive centers is evoked. Its application to 4 solid organic systems brought into reaction with chlorine gas allows the interpretation of the experimental results obtained, thanks to definite knowledge of the crystal structures of these systems. In the cases studied, it can be noted that the reactivity of a phenol molecule in a supramolecular entity decreases when the crystal arrangement consists of supramolecules linked only by Van der Waals type bonds. The reactivity increases for one particular multimolecular system which consists of a three-dimensional hydrogen bond lattice

Reactivity Dependence on the Crystalline State. Reaction of Gaseous Chlorine on Solid Phenols

Abstract Reaction of gaseous chlorine on powders of 3, 5-dichlorophenol (A), 2, 6-dimethylolphenol (B), 1: 1 molecular compound between A and B (C) and the mixture of equimolar amounts of powders of A and B (D) is studied under different experimental conditions. When the molecules are engaged in the compound C, the reactivity of the least reactive molecules (A) decreases while the reactivity of the most reactive molecules (B) increases. An attempt is made to interpret the results from the crystalline structures of A, B and C.

Modification des Formes de Cristaux Organiques par Reaction Chimique Avec un Gaz

Abstract Experimentally we show that convex and concave decreases oforganic single crystals lead to the same modifications when the decreases are obtained either by a chemical or a physical way. The chemical decrease is obtained either by the action of gaseous chlorine on the phenol single crystal without any solvent or catalyst or by the action of isobutylene on single crystals doped with sulphuric acid. In convex decrease the crystal becomes round shaped while if the decrease is made in a cavity drilled in the solid, crystallographic faces appear.