Síntese e caracterização de [2]rotaxano: estudo conformacional em solução

Abstract

Rotaxanes molecules became an important model for studying supramolecular chemistry by theirs unique motions and characteristics. In this context, this work was based in the synthesis of three molecules. One secondary amine, one new molecular thread and one new [2]rotaxane molecule based on a succinamide station, in which non-symmetrical bulky groups were used, which allows rotamers to be obtained. Three reactional steps were performed; the first two aiming to obtain the molecular thread, and the third performed to obtained the [2]rotaxane, performed by clipping methodology, which consists of a multicomponent reaction in which the macrocycle is formed around the thread. Nuclear Magnetic Resonance (NMR) one-dimensional ( 1 H and 13 C) and two-dimensional ( 1 H- 1 H COSY,1 H- 13 C HSQC and 1 H- 13 C HMBC) techniques, Liquid Chromatography Triple Quadrupole Mass Spectrometry and Infrared Radiation were used successfully to characterize the products obtained. Furthermore, the thermal stability was studied using Thermogravimetric analysis and Differential Scanning Calorimetry. The thread was obtained in 61 % yield and the predominant conformers in solution were (Z,E). The [2]rotaxane molecule was obtained in 45% yield with (Z,Z) conformers predominant in solution and solid state. Thus, the new [2]rotaxane synthesized is a new model for intermolecular interactions study and the conformers distribution in interlocked molecules.