A series of new clathrate host molecules 1−15, each containing two 9-hydroxy-9-fluorenyl or analogous terminal groups attached to linear central units of different lengths and structural compositions, has been synthesized. Their crystalline inclusion compounds with a variety of organic guests − including amines, alcohols, ketones, and other di-

No abstract

iodine cell Fig. 2. Diagram of the experimental setup: MCP, multichannel plates; TR. transient recorder; PC, dedicated computer H P QS/20; PD, photodiode; INT, integrator: SMS, control of the stepping motor for frequency-doubling crystal. the detected ZEKE signal on the laser wavelength gives information on the rovihronic states of the ionized molecule.

No abstract

No abstract

Biphenyls having two hydroxy containing benzo condensed oligocyclic substituents in positions 2,2′ were synthesized to yield the crowded diols 5 – 10. These compounds proved successful clathrate hosts. Crystalline inclusion formation is reported and discussed with reference to structural parameters of the host molecules covering the bis‐fluorenol analogous host compounds 1–4.

A series of new clathrate host molecules 1-8 containing two bis(diarylhydroxymethy1) groups attached to different positions (2,2' or 8 , 8 ) of a 1,l'-binaphthyl frame have been synthesized. Their clathrate formation properties with organic guests including alcohols, amines, ketones, and other dipolar aprotic compounds or aromatic hydrocarbons are reported (74 examples of clathrates) together with the results of solvent competition experiments for the parent host compound. The inclusion formation and the clathrate stoichiometries depend on the structure of the host molecules in a systematic manner. The crystal structures of the free parent host 1 and its pyridine clathrate (1 : 3) have been determined by X-ray diffraction. The molecular structure of the host is similar in the two species involving an intramolecular hydrogen bond between the host hydroxyls. No other hydrogen bond is involved in the free host case while in the pyridine inclusion compound the second host hydroxyl forms a hydrogen bond with the nitrogen of one pyridine guest which is surrounded by two unbound pyridine species such as to form clusters of three pyridine guests enclosed in the cavities between the host molecules. Thermal analysis corresponds with the two binding states of the pyridine molecules in the clathrate.Organic compounds that form crystalline host-guest inclusions (clathrates)" with secondary molecules are attracting increasing attentionc3] in view of their practical uses. These include chemical separation, stabilization and protection of labile species, topochemistry or development of new solid materials['-71. This has stimulated the development of new strategies in crystalline inclusion formation and motivated the design of novel host types[%31. The most consistent results refer to inclusion compounds which are based on coordination-assisted clathrate formation between functionalized and polar guest molecules[81. The formation and stability of these crystalline complexes are affected by functional as well as by topological complementarity, and consequently are sensitive to small structural variations[9~'01.Among the many new types of polar host structures[',2~8-'01, the hydroxylic group-containing molecules, in particular those involving triarylmethanol and bridged triarylmethanol units, were found to be very effective clathrate formers ['."-'31 . Fr om the geometric point of view, the scissor-type hosts based on the 1,l'-binaphthyl frame proved particular s~c c e s s f u l [~~~~~~~~. We report here on the synthesis of several specified compounds 1-8 that combine both (1 -7) have different polar and apolar substituents in different positions attached to the lateral aromatic rings. Moreover, linkage of the basic construction elements is also different (2,2' or 83' with reference to the binaphthyl unit, cf. 1 vs. 8) making possible a comprehensive evaluation of the host structures. We describe in detail the crystal inclusion properties of 1 -8, including guest competition experiments for 1 and present crystal structures of the ...

Zur enantioselektiven Chlatratbildung und Sorption eignen sich die Enantiomere des neuartigen Atropisomers 1. Racemisches 1 ist aus 2,2′‐Dibrombiphenyl und Fluorenon leicht zugänglich; das (S)‐(+)‐Enantiomer läßt sich mit (−)‐Fenchon unter Bildung eines schwerlöslichen Einschlußkomplexes abtrennen. Der Einsatz dieser Atropisomere in der Analytik und in der asymmetrischen Synthese zeichnet sich ab.