Desorption kinetics of a xanthenol-dioxane clathrate

The host xanthenol compound forms a 1:1 clathrate with dioxane, namely 9-(1-naphthyl)-9H-xanthen-9-ol–1,4-dioxane, C23H16O2·C4H8O2. The structure of this clathrate is reported, along with a study of the kinetics of desolvation and the determination of an activation energy. The guest mol­ecules are stabilized by Ohost—H⋯Oguest hydrogen bonds [O—H = 0.968 (2) Å, O⋯O = 2.7532 (13) Å and O—H⋯O = 151.9 (4)°]

Crystallization of two forms of a cyclodextrin inclusion complex containing a common organic guest

The isolation and structural elucidation by single crystal Xray diffraction of triclinic and monoclinic modifications of an inclusion complex of b-cyclodextrin with the same guest, methylparaben, are reported

Selectivity of amides by host-guest inclusion

The mechanism of selectivity by enclathration of four amides, N-methylformamide (NMF), dimethylformamide (DMF), N-methylacetamide (NMA) and dimethylacetamide (DMA), has been investigated by employing a bulky, flexible host. We measured the two-component selectivity curves for a mixture of amides, whose proportions in the crystals were determined by 1 H NMR spectroscopy. The crystal structures of the single guest inclusion compounds were elucidated and analyzed. The subtle changes in the torsional flexibility of the host were correlated to the selectivity. The packing factor, which represents the occupied vs. available space by the guest in the crystal structures correlates with the measured selectivities

The Dutch Resolution Method: Attempted Enhanced Selectivity of 2-Butylamine with Mixed Diol Hosts

The Dutch resolution method was employed to resolve 2-butylamine. Four similar diol host compounds were utilized singly and in combination to obtain inclusion compounds that displayed partial enantiomeric selectivity. However, the combination of any pair of host compounds did not significantly improve the enantiomeric excess of the 2-butylamine over that given by single host compounds. We attribute the results to the constant packing patterns of the structures

Quininium mandelates—a systematic study of chiral discrimination in crystals of diastereomeric salts

The resolution of racemic modifications by a chiral resolving agent is generally achieved either by diastereomer salt formation or by inclusion with a chiral host compound. The former method is the most common, and has been reviewed.1 The cinchona alkaloids, of which quinine is the most abundant, have been used extensively as resolving agents for acids1,2 and the pairs quinine/quinidine and cinchonidine/ cinchonine have been described as ‘‘quasi-enantiomeric’’.3 Larsen4,5 has described the structures of the salts formed by cinchonine and cinchonidine with both (R)- and (S)-mandelic acids. She concluded that cinchoninium (R)-mandelate is the less soluble salt and its structure displays disorder in the –CH=CH2 moiety. In contrast, cinchonidinium-(S)-mandelate is the less soluble salt. The thermal and solubility parameters of the four salts were reconciled with their crystal structures and it was noted that the packing of the cinchonidinium salts was significantly different from their corresponding cinchoninium salts. We have taken a somewhat different approach to the question of enantiomeric resolution in order to understand the mechanism of the molecular recognition that drives the differentiation of the resolving agent for one particular enantiomer. We have thus set up a series of competition experiments where the resolving agent, quinine (QUIN) was exposed to mixtures of mandelic acid, where the mole fraction of the starting mixture was varied systematically. The ensuing solutions were allowed to crystallise and the mole fraction of the entrapped enantiomer was measured by analysing the crystal structure

Complexation with diol host compounds. part 36:inclusion compounds of 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol with benzene, toluene and mesitylene.

The title compound 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol (H) forms inclusion compounds with benzene, toluene and mesitylene. H·C6H6 (1) and H· 34 C7H8 (2) crystallize in the triclinic space group P(-1) with unit cell dimensions for 1: a = 13.001(3) Å, b = 15.284(3) Å, c = 16.744(3) Å, α = 99.26(3)°, β = 74.78(3)°, γ = 64.96(3)°, Z = 4 and for 2: a = 12.922(3) Å, b = 15.159(3) Å, c = 16.562(3) Å, α = 68.12(3)°, β = 73.99(3)°, γ = 66.00(3)°, Z = 4. The hydroxyl groups of adjacent host molecules are involved in hydrogen bonding. H·C9H12 (3) exhibits a different packing arrangement with weak hydrogen bonding between the hydroxyl hydrogen of the host and the phenyl ring of the guest. The crystal system of compound 3 is monoclinic with space group C2/c, a = 23.750(5) Å, b = 8.4746(17) Å, c = 17.760(4) Å, α = 90°, β = 123.40(3)°, γ = 90°, Z = 4. The thermal behaviour of these compounds has also been studied

Inclusion compounds (macroproperties from structure)

Nous avons étudié des composés d'inclusion et résolu leurs structures. Nous avons étudié les propriétés physico-chimiques de dérivés de xanthenol en procédant à l'étude de la cinétique de désorption et à des expériences d'échanges de composés guest'. Nous avons purifié un composé par recristallisation. Nous avons étudié un cas de polymorphisme et déterminé la sélectivité d'un composé host' avec des solvants aromatiques. Enfin, nous avons fait l'inclusion de DMSO dans tous les composé host' et relié leur stabilité thermique avec leur morphologie. Pour WEB22, nous avons étudié sa sélectivité vis-à-vis de la pyridine et d'isomères de picoline. Pour H1 et H2, nous avons obtenus des composés d'inclusion avec des solvants et des terpènes dont nous avons étudié l'inclusion au moyen de spectres de PXRDLYON1-BU.Sciences (692662101) / SudocSudocFranceF