Structures and inclusion properties of racemic and enantiopure dimethyl and diphenyl 9,9'-bianthryl-2,2'-dicarboxylates.

The authors prepared the dimethyl and diphenyl esters of 9,9'-bianthryl-2,2'-dicarboxylic acid in racemic and enantiopure (M) forms. The enantiopure dimethyl ester forms inclusion compounds with various organic compounds such as benzene, methanol, phenol, and aniline whereas the racemic form does this only with benzene. No guest molecules are included by the racemic and enantiopure diphenyl esters. These effects of substituents and homochirality on the inclusion properties are discussed on the basis of X-ray structures of some inclusion and guest-free compounds.

Inclusion of volatile guests by a tetrapedal host: structure and kinetics.

The host compound tetra(3-hydroxy-3,3-diphenyl-2-propynyl)ethene, TET, forms inclusion compounds with acetone, dimethyl sulfoxide, dioxane and pyridine. All the structures were successfully solved in the triclinic space group P1[combining macron]. We found variable host : guest ratios for the acetone (TET.ACE, H : G = 1 : 4), dimethyl sulfoxide (TET.DMSO, H : G = 1 : 4) and pyridine compounds (TET.PYR, H : G = 1 : 5). Solutions of the host compound and dioxane formed TET.2DIOX, H : G = 1 : 2 when left to crystallise at room temperature, whereas TET.4DIOX, H : G = 1 : 4 was formed during crystal growth at low temperature. We have correlated the structures with their thermal stabilities and kinetics of desolvation.

The important role of solvent vapor in an organic solid state reaction.

Some organic reactions in the solid state proceeded very efficiently and selectively in the presence of a small amount of solvent vapor.

Isolation of axial conformers of chloro- and bromocyclohexane in a pure state as inclusion complexes with 9,9'-bianthryl, and the discovery of a novel 1,3 diaxial Cl...H weak interaction.

The axial conformers of chloro- and bromocyclohexane were isolated in a pure state as inclusion complexes with 9,9'-bianthryl, and a 1,3 diaxial Cl...H weak interaction was discovered by X-ray analysis of the axial conformer of chlorocyclohexane.

A new [2 + 2] photodimerization of 5-chloro- and 5-methyl-2-pyridone in their inclusion complexes with 1,1'-biphenyl-2,2'-dicarboxylic acid as a model for DNA damage by photodimerization of its thymine component.

As a model for DNA damage by photodimerization of its thymine component, a new [2 + 2] photodimerization of 5-chloro and 5-methyl-2-pyridone to the corresponding cis-anti-dimers as their inclusion complexes with 1,1'-biphenyl-2,2'-dicarboxylic acid was found, and the mechanism of this stereoselective solid state reaction was studied by X-ray analysis.

Isolation of equatorial conformers of chloro- and bromocyclohexane in a pure state as inclusion complexes with a host compound.

The equatorial conformers of chloro- and bromocyclohexane were isolated in a pure state as inclusion complexes with a host compound, and their structures were studied by IR spectra and X-ray analysis.

A novel transformation of a 1 : 1 : 1 racemic complex of 2,2'-dihydroxy-1,1'-binaphthyl, Me4N+ Cl- and MeOH into a conglomerate in the solid state by heating or contact with MeOH vapour.

The title racemate-to-conglomerate transformation which occurs in the solid state on heating or contact with MeOH vapour has been studied by IR and DTA spectral measurements, microscopic observation, and by X-ray structural and X-ray powder diffraction analysis.

Efficient resolution of 2,2'-dihydroxy-1,1'-binaphthyl by inclusion complexation with chiral N-(3-chloro-2-hydroxypropyl)-N,N,N-trimethylammonium chloride.

The complete resolution of 2,2[prime or minute]-dihydroxy-1,1[prime or minute]-binaphthyl into its enantiomers by inclusion complexation with a commercially available derivative of choline, is reported. The two enantiomers are recovered in >99% ee from the inclusion complexes by simple dissolution in a diethyl ether-water medium and the resolving agent can be recycled.

Isolation of an inclusion complex of naphthol and its benzoate as an intermediate in the solvent-free benzoylation reaction of naphthol.

Solvent-free benzoylation of naphthol was found to proceed via an inclusion complex intermediate of the naphthol and its benzoate by IR spectral monitoring.

Mechanochemistry and co-crystal formation: effect of solvent on reaction kinetics.

We demonstrate that significant improvements in kinetics of co-crystal formation by grinding can be achieved by the addition of minor amounts of appropriate solvent.

A new supramolecular system of racemic-bis-beta-naphthol, benzoquinone and aromatic hydrocarbon, which shows high molecular recognition ability.

Racemic-bis-beta-naphthol, benzoquinone and aromatic hydrocarbons formed a new three component supramolecular system as black crystals. X-ray analysis of the crystals shows that (+)- and (-)-bis-beta-naphthol and benzoquinone form a quinhydrone-type crystalline lattice with aromatic stacking and hydrogen bonding in which the third aromatic hydrocarbon component is accommodated. As the cavity created has a definite shape and size, only hydrocarbons which fit the cavity are selectively included.

Chiral inclusion crystals constructed with achiral host and achiral guest molecules.

Achiral molecules of tetrakis(p-bromophenyl)ethylene and 2,3,6,7,10,11-hexahydroxy triphenylene were found to arrange in a chiral form in their inclusion crystal with an achiral guest molecule. The chiral arrangement of these achiral molecules was studied by X-ray analysis and CD spectral measurement in the solid state.

Enantioselective Photocyclization of N-Alkylfuran-2-carboxyanilides to trans-Dihydrofuran Derivatives in Inclusion Crystals with Optically Active Host Compounds Derived from Tartaric Acid.

The steric course of the photocyclization reaction of the title achiral compounds (1) to optically active trans-dihydrofuran derivatives (2) was controlled by carrying out the reaction in inclusion crystals (4) with optically active hosts (3) derived from tartaric acid. The mechanism of the enantioselective reaction of 1 in 4 was studied by X-ray structural analysis of 4. In some cases, the steric course of the photoreaction was different depending on whether 4 was prepared by recrystallization or by mixing of 1 and 3.

Enantioselective Photochemical Reactions of N-Phenyl Enaminones in Inclusion Complex Crystals Using a Chiral Host Compound.

Enantioselective reaction of N-methyl-N-phenyl-3-amino-2-cyclohexen-1-one derivatives to the corresponding N-methylhexahydro-4-carbazolones has been accomplished by photolysis in a water suspension of 1:1 inclusion compounds of the starting material with optically active host compounds derived from tartaric acid. 3-(N-Methylanilino)-2,5,5-trimethyl-2-cyclohexen-1-one formed two kinds of dimorphous crystals, and one of these gave an optically active carbazolone derivative by photolysis, but the other one was photochemically inert. X-ray structure analysis showed that two reaction centers, the phenyl and cyclohexenone groups of the reactant, are located in close and distant positions respectively in these two inclusion compounds.

Extremely Long C-C Bond in (-)-trans-1,2-Di-tert-butyl-1,2-diphenyl- and 1,1-Di-tert-butyl-2,2-diphenyl-3,8-dichlorocyclobuta[b]naphthalenes.

The sterically bulky t-Bu-substituted derivatives of 1,1,2,2-tetraphenyl-3,8-dichlorobuta[b]naphthalene (5), trans-1,2-tert-butyl-1,2-diphenyl- (8) and 1,1-di-tert-butyl-2,2-diphenyl-3,8-dichlorocyclobuta[b]naphthalene (12), were prepared. X-ray analysis of 8 and 12 at 150 K showed that C-C bonds of 8 and 12 are 1.686 and 1.729 Å, respectively. The latter bond length is longer than that of 1.720 Å in 5 and is the longest one reliably determined to date.

Stereoselective Thermal Conversion of s-trans-Diallene into Dimethylenecyclobutene via s-cis-Diallene in the Crystalline State.

A conrotatory [2+2] cyclization is the second step in the solid-state thermal reaction of s-trans-tetraaryldibromohexatetraenes 1 to cyclobutenes 4. Prior to the cyclization 1 rearranges into the cis conformer 3. Surprisingly the thermal rearrangement and the stereoselective cyclization occur readily in spite of the required motion of the sterically bulky substituents. R=Ph, p-MeC6 H4 .

Unusual Disordered Crystal Structure of a Racemate Exhibiting a Novel Enantiomeric Resolution: Preferential Enrichment.

Simple recrystallization of racemic (±)-NC leads to preferential enrichment of one enantiomer in the mother liquor, which allows the efficient resolution of the two enantiomers. In the unique disordered crystal structure of the racemate, the two enantiomers form centrosymmetric dimers as the major component.