Mit 7 Indikatorverbindungen wie z.B. 4‐Nitro‐anisol, 1‐Äthyl‐4‐nitro‐benzol und N,N‐Diäthyl‐4‐nitro‐anilin, deren p ‐ 1r ‐ oder 1r ‐ 1r ‐Übergänge im experimentell gut zugänglichen Bereich liegen, werden die solvatochromen Effekte von Lösungsmitteln auf die Elektronenspektren bestimmt, die von der Polarität und Polarisierbarkeit des Lösungsmittels abhängen.

No abstract

Wide deviations (enhanced stabilities) from a linear relationship between the corresponding stability constants (given as Gibbs standard free energies of complexing) for gaseous Li+ and H+ adducts of monodentate diazines and pyridines are found for pyridazine, 2-fluoropyridine, and 1 Jbnaphthyridine. These results are interpreted to indicate the formation of a bidentate ring structure for the latter three compounds (and others of similar structures) with Li+ but not with H+. Ab initio calculations of structures and energies show the most stable forms of all of the H+ adducts to be monodentate, whereas threeand four-membered-ring bidentate structures are confirmed for the Li+ adducts of the three above-mentioned compounds. The charge distributions obtained support the previous conclusion that bonding to H+ is largely covalent, whereas that to Li+ is largely ionic.

No abstract

No abstract