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The X-ray crystallographic structures of 18 fluorinated N-phenylmaleimides and corresponding phthalimides of different degree and positions of fluorine substituents, including two compounds each in two polymorphic forms, have been determined in order to study the effect of fluorine substitution on the solid state organization in competition with stronger oxygen and nitrogen H-acceptor sites. The data suggest that C−H···O contacts formed in the crystalline packings play the dominant role but C−H···F contacts are also of relevance with the fluorine atoms being more specific in making a selection from potential hydrogen contacts. The F···F and F···π Fcontacts observed are rather secondary in these structures and mostly determined by the packing. Unexpectedly, a π···π Finteraction is found only in two exceptional cases for dimer formation contradicting the common opinion of π···π Fstacking as being a robust supramolecular synthon. [ABSTRACT FROM AUTHOR]

By applying the “wheel-and-axle”host concept andincorporating a previously developed heteroaromatic substitution strategy,a new type of diol host featuring two di(benzo[b]thien-2-yl)hydroxymethylunits attached to both ends of a central ethynylene (3) and 1,4-phenylene (4) moiety is reported. The synthesesof the host compounds are described, and solvent inclusion formationvia crystallization has extensively been studied showing a remarkableinclusion capability of the compounds. X-ray diffraction analysisof relevant crystal structures have been performed and comparativelydiscussed. Vapor sorption behavior of the compounds as solid receptorfilms coated on a quartz crystal microbalance considering a varietyof solvent vapors has been scrutinized, indicating potential applicationas mass sensitive materials. [ABSTRACT FROM AUTHOR]

The diol host compound 2,2′-bis(hydroxydiphenylmethyl)-1,1′-binaphthyl crystallised in three different polymorphic structures, and formed a series of inclusion compounds with pyridine, morpholine and benzene. Different stoichiometries were obtained by manipulating the proportions of the guests and the crystallisation temperatures. A number of these compounds are isostructural and the guests are located at fixed sites in the crystal structure. Structural similarities were interpreted viaHirshfeld surface fingerprint plots. The results of thermal analysis of one structural group were explained in terms of the host⋯guest interactions. [ABSTRACT FROM AUTHOR]

This study investigates the selectivity of two organic host molecules towards pairs of guest molecules and in particular describes the crystal structures of the mixed guest clathrates obtained in selectivity studies. The diol organic host compounds 9,9′-(biphenyl-4,4′-diyl)difluoren-9-ol (H1) and 9,9′-(ethyne-1,2-diyl)difluoren-9-ol (H2) investigated in this study were found to show interesting selectivities (determined via competition experiments) towards THF vs. Et2O and EtOH vs. MeCN, respectively. The crystal structures of the single guest inclusion compounds were elucidated and compared and in addition the crystal structures of the inclusion compounds containing mixed guests were studied and in each case could be correlated with the selectivity profiles. [ABSTRACT FROM AUTHOR]

Investigation of the selectivities of two diol organic hosts for pairs of small organic guests gave interesting results which could be correlated with the crystal structures of the inclusion compounds containing mixtures of the two guests; these structures were compared with those of the single guest inclusion compounds. [ABSTRACT FROM AUTHOR]

The formation of crystalline host–guest complexes of three constitutionally isomeric host compounds 1–3featuring two diphenylhydroxymethyl groups attached in different positions to a biphenylylene central moiety is studied. Dependent on the connection mode (2,2′-, 3,3′-, or 4,4′-) with reference to the biphenylylene unit, a distinctly different complex behavior of the host compounds is observed. X-ray crystal structures of the solvent-free hosts are reported including a third polymorph with respect to already known polymorphous structures. The crystal structures of eight host–guest complexes of 1–3, including a pair of complexes differing only in the host/guest stoichiometry, are described and comparatively discussed covering the structures of known complex species of the isomeric hosts. Correlations between the constitutional isomerism of the host molecules and their conformational as well as packing structures in the crystalline state, both in unsolvated and solvent complexed form, are demonstrated providing potential usefulness in the future design of crystalline host–guest complexes. [ABSTRACT FROM AUTHOR]

The host compound 1,4-bis(diphenylhydroxymethyl)benzene is shown to include a series of amides: N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), N-methylacetamide (NMA) and N-methylformamide (NMF). The resultant inclusion compounds were characterised using thermal analysis and single crystal X-ray diffraction. A kinetic experiment was performed on the DMF clathrate and the activation energy determined. The host selectivity for the amides was studied through competition experiments. [ABSTRACT FROM AUTHOR]

The X-ray crystal structure of an acetonitrile solvate of 5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25,27-dimethoxycalix[4]arene that is 1a, showing the unusual coexistence of two basic conformations in the crystal, that is, coneand 1,2-alternate, is analyzed. In contrast to this conformational coexistence of crystallographically independent molecules, the predominant conformation in solution and also in the related toluene (1b) and toluene/acetonitrile (1c) solvates is the coneconformation. With the help of calculations on the ground state energy of the single conformers and DSC measurements as well as crystallization experiments of 1in toluene/acetonitrile mixtures of different ratio a possible explanation of this phenomenon is given. [ABSTRACT FROM AUTHOR]

Crystal structures of the configurational isomers of benzil monoxime (1and 2), a p-methoxy derivative (3) and its solvated species with triethylamine (3a) are reported showing specific influences of the molecular configuration, substitution and solvation on the conformational property and packing behaviour of the molecules. Based on the observed interdependences, in particular involving modes of interaction, potential utilization of the 1,2-dione monoxime functional unit for the purpose of crystal engineering seems promising. [ABSTRACT FROM AUTHOR]

Three upper rim site lipophilic calix[4]arenes 1–3featuring different para-alkanoyl substituents at the phenolic moieties, i.e.n-hexanoyl, n-octanoyl and 3-cyclohexylpropanoyl groups, are reported to complex, aside from the common solvent molecule n-butanol, different keto and hydroxylic terpene guest molecules such as (−)-menthone, (−)-menthol or (+)-carvone in the solid state. Although for all six inclusion compounds described here, a strict 1 : 1 host : guest stoichiometry is observed, complementary size and polarity relationships between the cone shaped calixarene cavity and the guest molecule emerge from single crystal X-ray structural study. Dependent on the structure of the guest molecule, the calixarenes are arranged in a head-to-head or head-to-tail orientation in the crystalline packing, giving rise to capsular or otherwise deeply enclosed inclusion mode of the guest molecules, respectively. Furthermore, the O-acyl atoms of the calixarenes were found to be directly involved in host–guest interaction. In order to estimate the degree of isostructurality of the host frameworks and to examine the influence of the guest molecules on the solid-state conformation of these calixarene molecules, isostructurality comparison, cell similarity and molecular isometricity calculations were carried out revealing a rare case of supramolecular morphotropism for the pair of (−)-menthone and (−)-menthol inclusions of the n-hexanoyl substituted calixarene. Structure–inclusion property relationship was examined by QMB measurements of thin layers of the calixarenes. Vapor studies with different terpenes and common organic solvents show an increased affinity towards guest molecules with polar functionalities, whereas small solvent molecules like acetone are bound considerably better than the more bulky terpene molecules. [ABSTRACT FROM AUTHOR]

The ability to form self-assembled layers on gold (Au) using five organosulfur compounds that contain isomerizable groups has been investigated. The isomerizable groups are either stilbene or diketoarylhydrazone derivatives. To anchor them on a gold surface, the isomerizable groups have been combined with sulfur-containing groups (disulfide, 1,2-dithiolane, and thiophene). The resulting thin films assembled on gold were characterized by X-ray photoelectron spectroscopy (XPS), infrared (FTIR) reflectance spectroscopy, ellipsometry, and water contact angle measurements. Though all substances have the potential to form self-assembled monolayers (SAMs), only two of them, disulfanediyl-bis(ethane-2,1-diyl) bis(4-styrylbenzoate) (1) and 4-(2,4-dioxo-3-pentylidene)diazane-2,2,1-triylphenyl thioctate (4), yield the expected structure, the latter one showing the possibility to incorporate diarylketohydrazone moieties into SAMs. The compound 4-(2,4-dioxo-3-pentylidene)diazane-2,2,1-triylphenyl thiophene-2-carboxylate (5) does not self-assemble on gold, but 4-styrylphenyl thioctate (3) presumably forms multilayers. In the case of disulfanediyl-bis(ethane-2,1-diyl) bis4-(p-nitrostyryl)benzoate (2), we propose a structure with a fraction of the molecules bound to gold via the nitro group. The results show that the propensity of organosulfur compounds to self-assemble on gold not only is determined by the sulfur-containing group but also is affected by the complete molecule. [ABSTRACT FROM AUTHOR]

New fluorinated host compounds, namely, 2,4,6-tris(4-bromo-3-fluorophenoxy)-1,3,5-triazine, 2,4,6-tris(4-bromo-3,5-difluorophenoxy)-1,3,5-triazine, and 2,4,6-tris(4-bromo-2,6-difluorophenoxy)-1,3,5-triazine, were synthesized to investigate the effect of fluorine on the inclusion behavior. The altered electrostatic potential of the channel wall caused by fluorine substituents led to essential differences in host−guest interactions which were demonstrated by the inclusion of large guest molecules such as fullerenes, decamethylferrocene, or bucky-ferrocene. [ABSTRACT FROM AUTHOR]