Variable temperature 1H and 13C NMR study of restricted rotation in N,N-bis(2-hydroxyethyl)acetamide

N,N-bis(2-hydroxyethyl)acetamide shows restricted rotation about the amide bond in both 1H and 13C NMR spectra rendering the two hydroxyethyl groups non-equivalent. A variable temperature study in CD3SOCD3 allowed estimation of the free energy barrier to rotation as 75.6 ± 0.2 kJ mol–1. Previously published data in CDCl3 appears to be erroneous.PostprintPeer reviewe

Variable temperature ¹H and ¹³C NMR study of restricted rotation in <i>N,N</i>-bis(2-hydroxyethyl)acetamide

N,N-bis(2-hydroxyethyl)acetamide shows restricted rotation about the amide bond in both 1H and 13C NMR spectra rendering the two hydroxyethyl groups non-equivalent. A variable temperature study in CD3SOCD3 allowed estimation of the free energy barrier to rotation as 75.6 ± 0.2 kJ mol–1. Previously published data in CDCl3 appears to be erroneous

Synthesis and properties of polyaromatic dendrimers possessing a repetitive amideester coupling sequence

A series of novel polyaromatic dendrimers that feature tris-(2-ethylamino)amine as the central core unit has been synthesized up to the third generation by employing a convergent growth strategy. The building blocks 1,3-diamino-2-hydroxypropane and 4-carboxybenzaldehyde were used for dendron construction, a process that involved the cyclic repetition of esterification, oxidation and selective amidation steps. Molecular modelling of this class of dendrimers has been used to predict potential solution state conformations employing molecular mechanics and molecular dynamic simulations. In addition, the results of preliminary metal binding studies using the first generation dendritic system are also outlined. (C) 2003 Elsevier Science Ltd. All rights reserved.</p