Exploring the Limits of Intramolecular London Dispersion Stabilization with Bulky Dispersion Energy Donors in Alkane Solution.

We present an experimental study of a cyclooctatetraene-based molecular balance disubstituted with increasingly bulky -butyl (Bu), adamantyl (Ad), and diamantyl (Dia) substituents in the 1,4-/1,6-positions for which we determined the valence-bond shift equilibrium in -hexane (hex), -octane (oct), and -dodecane (dod). Computations including implicit and explicit solvation support our temperature-dependent NMR equilibrium measurements indicating that the more sterically crowded 1,6-isomer is always favored, irrespective of solvent, and that the free energy is quite insensitive to substituent size.

Completing the series of boron-nucleophilic cyanoborates: boryl anions of type NHC-B(CN).

Since the first seminal report of boron-centred nucleophiles, the area of boryl anions has developed only sporadically and requires further systematisation. The boryl anions of type NHC-B(CN) (NHC = N-heterocyclic carbene) described herein complete a consistent series with the known anions cAAC-B(CN) [cAAC = cyclic(alkyl)(amino)carbene] and B(CN). A novel approach towards NHC-stabilised cyanoboranes based on alkylthio-cyano exchange at boron is presented, and in contrast to other methods affords the products in better purity and yield.

Study of acid-base equilibria of fleroxacin.

The acid-base equilibria of fleroxacin were studied by means of potentiometry and spectrophotometry. It was established that fleroxacin undergoes a complex acid-base equilibrium due to its zwitterionic nature and two proton-binding sites of similar acidity. The stoichiometric equilibrium constants were determined at 25 degrees C and constant ionic strength 0.

Spectrophotometric investigation on complex formation of captopril with palladium(II) and its analytical application.

The formation of the complex between captopril and palladium(II) chloride in Britton-Robinson buffer solution was studied. It has been established that captopril reacts with palladium(II) chloride in the pH range 2.14-9.