Nitro- and fluoropolyformals. III. Copolyformals from mixtures of fluoro- and nitro-α,ω-diols

Polyformals of fluoro-, nitramine-, and C-nitrodiols show widely differing properties with respect to glass transition temperature, melting transition, and solubility. Polymers with desirable combinations of these properties, e.g., low T_g, high nitro content, and good solubility in polar solvents, were expected to result from acid-promoted copolycondensation of appropriate mixtures of diols with formaldehyde. A series of such condensations were carried out and the polymers obtained from binary mixtures of fluoro- and nitrodiols, different nitrodiols, and fluoro- or nitrodiols and carboranediols, were characterized by GPC, ¹H-NMR, and DSC analysis.     

Torsional isomerization of biologically active bicyclic molecules

Rotational isomerization of bipyridines C₅H₄N? C₅H₄N was studied by CNDO /2, PPP /CI , and CNDO /CI methods. It is shown that CNDO /2 overestimates the angle of rotation ? between the pyridine rings ca. two times. The angle ? was determined for 2,2′-bipyridine by means of correlation of the theoretical (CNDO /2) and experimental dipole moment. It was also found from the correlation between the theoretical and experimental UV spectra. It is shown that there is an explicit dependence of the results upon the distance between heteroatoms (PPP /CI ). It has been found that the CNDO /CI method correctly predicts the value of the rotational angles and their sequence in bipyridines.     

Intermediate changes in high energy elastic scattering from atoms

Correction of the Glaubner T-matrix to account for target particle motion and energy change in elastic scattering of charged particles from atomic systems is found to vanish to leading order.     

Einen Apparat zur Entwickelung reiner Kohlens?ure

Ohne Zusammenfassung