Ueber die Anwendung der calorimetrischen Bombe

Ohne Zusammenfassung     

New 3π‐2Spiro Ladder‐Type Phenylene Materials: Synthesis,Physicochemical Properties and Applications in OLEDs

New routes to ladder‐type phenylene materials 1 and 2 are described. The oligomers 1 and 2 , which possess a “3π‐2spiro” architecture, have been synthesized by using extended diketone derivatives 3 and 10 as key intermediates. The physicochemical properties of the new blue‐light emitter 2 were studied in detail and compared with those of the less‐extended 1 . Owing to the recent development of fluorenone derivatives and their corresponding more conjugated analogues as potential electron‐transport materials in organic light‐emitting diodes (OLEDs) and as n‐type materials for photovoltaic applications, we also report herein the thermal, optical and electrochemical behavior of the key intermediates, diketones 3 and 10 . Finally, the application of dispiro 2 as a new light‐emitting material in OLEDs is reported.     

Effets de substituant sur la fréquence hydroxyle de phenols associés à des hydrocarbures benzéniques par liaison d'hydrogene

The electronic effects of X substituents in aromatic molecules XC₆H₅, XC₆H₄Me and XC₆H₄OMe are studied by measurements of the bonded OH frequencies of phenol-π-base complexes. A judicious choice of the experimental conditions (solvent, π-base concentration, phenol acidity, temperature) permits the following substituents to be studied: Me, Et, CH(Me)₂, OMe, OEt, OC₆H₅, NHMe, N(Me)₂, N(Et)₂, NHC₆H₅, C₆H₅, CHCH₂, CCH, CCMe, SMe, SC₆H₅, F, Cl, Br and I.Halogenated benzenes, benzotrichloride and benzotrifluoride were found to act solely as π-bases. Electronic effects are accurately measured by means of the linear combination ?₁σ₁ + ?_R?°_R. The ratio ?_R/?₁ shows that inductive and mesomeric effects are of the same importance. This ratio may be considered as an argument in favour of the symmetric configuration of the complex. Electronic effects are found to be additive in disubstituted benzenes.     

Hydrogen-bond accepting strength of protonated nicotine

Recent crystal structures of nicotine bound to the acetylcholine binding protein (AChBP) ended a long debate confirming that the pyridine nitrogen of nicotine is indeed hydrogen-bonded to receptor residues through a bridging water molecule. Here, we describe the first direct experimental evaluation of the hydrogen-bond affinity of the nicotinium pyridine nitrogen. The equilibrium constant of its association with a phenol is 1 order of magnitude greater than the association of the acetylcholine carbonyl oxygen.     

Stereoselective synthesis of P-chirogenic dibenzophosphole-boranes via aryne intermediates

A new aryne-mediated tandem cross-coupling/P-cyclization sequence starting from tertiary phosphine-boranes and 1,2-dibromobenzenes is reported. P-chirogenic dibenzophospholes become accessible in a regio-, chemo-, and diastereoselective way.